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Sample records for related ore formation

  1. A geochemical assessment of possible lunar ore formation

    Science.gov (United States)

    Haskin, Larry A.; Colson, Russell O.; Vaniman, David

    The Moon apparently formed without appreciable water or other relatively volatile materials. Interior concentrations of water or other volatile substances appear to be extremely low. On Earth, water is important to the genesis of nearly all types of ores. Thus, some have reasoned that only abundant elements would occur in ore concentrations. The definition and recognition of ores on the Moon challenge the imaginations and the terrestrial perceptions of ore bodies. Lunar ores included solar-wind soaked soils, which contain abundant but dilute H, C, N, and noble gases (including He-3). Oxygen must be mined; soils contain approximately 45 percent (wt). Mainstream processes of rock formation concentrated Si, Mg, Al, Fe, and Ca, and possibly Ti and Cr. The highland surface contains approximately 70 percent (wt) feldspar (mainly CaAl2Si2O8), which can be separated from some highland soils. Small fragments of dunite were collected; dunite may occur in walls and central peaks of some craters. Theoretical extensions of observations of lunar samples suggest that the Moon may have produced ores of trace elements. Some small fragments have trace-element concentrations 104 times higher than the lunar average, indicating that effective geochemical separations occurred; processes included fractional crystallization, silicate immiscibility, vaporization and condensation, and sulfide metamorphism. Operations of these processes acting on indigenous materials and on meteoritic material in the regolith could have produced ores. Infalling carbonaceous meteorites and comets have added water and hydrocarbons that may have been cold-trapped. Vesicles in basalts, pyroclastic beads, and reported transient events suggest gag emission from the lunar interior; such gas might concentrate and transport rare elements. Large impacts may disperse ores or produce them through deposition of heat at depth and by vaporization and subsequent condensation. The main problem in assessing lunar resources is

  2. Influence of sulfur dioxide-related interactions on PM2.5 formation in iron ore sintering.

    Science.gov (United States)

    Ji, Zhiyun; Fan, Xiaohui; Gan, Min; Chen, Xuling; Lv, Wei; Li, Qiang; Zhou, Yang; Tian, Ye; Jiang, Tao

    2017-04-01

    The formation of PM2.5 (aerosol particulate matter less than 2.5 µm in aerodynamic diameter) in association with SO2 emission during sintering process has been studied by dividing the whole sintering process into six typical sampling stages. A low-pressure cascade impactor was used to collect PM2.5 by automatically segregating particulates into six sizes. It was found that strong correlation existed between the emission properties of PM2.5 and SO2. Wet mixture layer (overwetted layer and raw mixture layer) had the function to simultaneously capture SO2 and PM2.5 during the early sintering stages, and released them back into flue gas mainly in the flue gas temperature-rising period. CaSO4 crystals constituted the main SO2-related PM2.5 during the disappearing process of overwetted layer, which was able to form perfect individual crystals or to form particles with complex chemical compositions. Besides the existence of individual CaSO4 crystals, mixed crystals of K2SO4-CaSO4 in PM2.5 were also found during the first half of the temperature-rising period of flue gas. The interaction between fine-grained Ca-based fluxes, potassium vapors, and SO2 was the potential source of SO2-related PM2.5. The emission property of PM2.5 and SO2 throughout the sintering process exhibited well similarity. This phenomenon tightened the relationship between the formation of PM2.5 and the emission of SO2. Through revealing the properties of SO2-related PM2.5 during sintering process, the potential interaction between fine-grained Ca-based fluxes, potassium vapors, and SO2 was found to be the source of SO2-related PM2.5. This information can serve as the guidance to develop efficient techniques to control the formation and emission of PM2.5 in practical sintering plants.

  3. Formation conditions of high-grade gold-silver ore of epithermal Tikhoe deposit, Russian Northeast

    Science.gov (United States)

    Volkov, A. V.; Kolova, E. E.; Savva, N. E.; Sidorov, A. A.; Prokof'ev, V. Yu.; Ali, A. A.

    2016-09-01

    The Tikhoe epithermal deposit is located in the Okhotsk-Chukotka volcanic belt (OChVB) 250 km northeast of Magadan. Like other deposits belonging to the Ivan'insky volcanic-plutonic depression (VTD), the Tikhoe deposit is characterized by high-grade Au-Ag ore with an average Au grade of 23.13 gpt Au and Au/Ag ratio varying from 1: 1 to 1: 10. The detailed explored Tikhoe-1 orebody is accompanied by a thick (20 m) aureole of argillic alteration. Pyrite is predominant among ore minerals; galena, arsenopyrite, sphalerite, Ag sulfosalts, fahlore, electrum, and küstelite are less abundant. The ore is characterized by abundant Sebearing minerals. Cu-As geochemical specialization is noted for silver minerals. Elevated Se and Fe molar fractions of the main ore minerals are caused by their formation in the near-surface argillic alteration zone. The veins and veinlets of the Tikhoe-1 ore zone formed stepwise at a temperature of 230 to 105°C from Nachloride solution enriched in Mg and Ca cations with increasing salinity. The parameters of the ore-forming fluid correspond to those of epithermal low-sulfidation deposits and assume the formation of high-grade ore under a screening unit of volcanic rocks. In general, the composition of the ore-forming fluid fits the mineralogy and geochemistry of ore at this deposit. The similarity of the ore composition and parameters of the ore-forming fluid between the Tikhoe and Julietta deposits is noteworthy. Meanwhile, differences are mainly related to the lower temperature and fluid salinity at the Julietta deposit with respect to the Tikhoe deposit. The fluid at the Julietta deposit is depleted in most components compared with that at the Tikhoe deposit except for Sb, Cd, and Ag. The results testify to a different erosion level at the deposits as derivatives of the same ore-forming system. The large scale of the latter allows us to predict the discovery of new high-grade objects, including hidden mineralization, which is not exposed at

  4. Mineralogy and geochemistry of banded iron formation and iron ores from eastern India with implications on their genesis

    Indian Academy of Sciences (India)

    Subrata Roy; A S Venkatesh

    2009-12-01

    The geological complexities of banded iron formation (BIF) and associated iron ores of Jilling–Langalata iron ore deposits, Singhbhum–North Orissa Craton, belonging to Iron Ore Group (IOG) eastern India have been studied in detail along with the geochemical evaluation of different iron ores. The geochemical and mineralogical characterization suggests that the massive, hard laminated, soft laminated ore and blue dust had a genetic lineage from BIFs aided with certain input from hydrothermal activity. The PAAS normalized REE pattern of Jilling BIF striking positive Eu anomaly, resembling those of modern hydrothermal solutions from mid-oceanic ridge (MOR). Major part of the iron could have been added to the bottom sea water by hydrothermal solutions derived from hydrothermally active anoxic marine environments. The ubiquitous presence of intercalated tuffaceous shales indicates the volcanic signature in BIF. Mineralogical studies reveal that magnetite was the principal iron oxide mineral, whose depositional history is preserved in BHJ, where it remains in the form of martite and the platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Removal of silica from BIF and successive precipitation of iron by hydrothermal fluids of possible meteoric origin resulted in the formation of martite-goethite ore. The hard laminated ore has been formed in the second phase of supergene processes, where the deep burial upgrades the hydrous iron oxides to hematite. The massive ore is syngenetic in origin with BHJ. Soft laminated ores and biscuity ores were formed where further precipitation of iron was partial or absent.

  5. Iron isotope and REE+Y composition of the Cauê banded iron formation and related iron ores of the Quadrilátero Ferrífero, Brazil

    Science.gov (United States)

    Mendes, Mônica; Lobato, Lydia M.; Kunzmann, Marcus; Halverson, Galen P.; Rosière, Carlos A.

    2016-04-01

    The Minas Supergroup banded iron formations (BIFs) of the Brazilian Quadrilátero Ferrífero (QF) mineral province experienced multiple deformational events synchronous with hypogene mineralization, which resulted in the metamorphism of BIFs to itabirites and their upgrade to high-grade iron ore. Here, we present rare earth element and yttrium (REE+Y) compositions together with iron isotope ratios of itabirites and their host iron orebodies from 10 iron deposits to constrain environmental conditions during BIF deposition and the effects of hypogene iron enrichment. The REE+Y characteristics of itabirites (positive Eu anomaly and LREE depletion) indicate hydrothermal iron contribution to the Minas basin. Iron isotope data and Ce anomalies suggest BIFs were precipitated by a combination of anoxic biological-mediated ferrous iron oxidation and abiotic oxidation in an environment with free oxygen (such as an oxygen oasis), perhaps related to increase in oxygen concentrations before the Great Oxidation Event (GOE). The similarity of the REE+Y composition of the itabirites from the different QF deformational domains, as well as to other Superior-type BIFs, indicates that the metamorphism and synchronous hydrothermal mineralization did not significantly affect the geochemical signature of the original BIFs. However, iron isotope compositions of iron ore vary systematically between deformational domains of the QF, likely reflecting the specific mineralization features in each domain.

  6. Iron isotope and REE+Y composition of the Cauê banded iron formation and related iron ores of the Quadrilátero Ferrífero, Brazil

    Science.gov (United States)

    Mendes, Mônica; Lobato, Lydia M.; Kunzmann, Marcus; Halverson, Galen P.; Rosière, Carlos A.

    2017-02-01

    The Minas Supergroup banded iron formations (BIFs) of the Brazilian Quadrilátero Ferrífero (QF) mineral province experienced multiple deformational events synchronous with hypogene mineralization, which resulted in the metamorphism of BIFs to itabirites and their upgrade to high-grade iron ore. Here, we present rare earth element and yttrium (REE+Y) compositions together with iron isotope ratios of itabirites and their host iron orebodies from 10 iron deposits to constrain environmental conditions during BIF deposition and the effects of hypogene iron enrichment. The REE+Y characteristics of itabirites (positive Eu anomaly and LREE depletion) indicate hydrothermal iron contribution to the Minas basin. Iron isotope data and Ce anomalies suggest BIFs were precipitated by a combination of anoxic biological-mediated ferrous iron oxidation and abiotic oxidation in an environment with free oxygen (such as an oxygen oasis), perhaps related to increase in oxygen concentrations before the Great Oxidation Event (GOE). The similarity of the REE+Y composition of the itabirites from the different QF deformational domains, as well as to other Superior-type BIFs, indicates that the metamorphism and synchronous hydrothermal mineralization did not significantly affect the geochemical signature of the original BIFs. However, iron isotope compositions of iron ore vary systematically between deformational domains of the QF, likely reflecting the specific mineralization features in each domain.

  7. Raman Spectroscopic Characterisation of Australian Banded Iron Formation and Iron Ore

    Science.gov (United States)

    Wells, M. A.; Ramanaidou, E. R.

    2012-04-01

    In Australia and world-wide over the past 5-10 years, declining reserves of premium, high-grade (>64% Fe), low-P bearing iron ore, have seen iron ore producers increase their utilisation of lower Fe-grade, higher P/Al/Si ore. In Australia, the channel iron deposits (CID), bedded iron deposits (BID) and, more recently, BIF-derived magnetite iron deposits (MID) have seen increased usage driven mainly by the increased demand from Chinese steel mills (Ramanaidou and Wells, 2011). Efficient exploitation and processing of these lower-grade iron ores requires a detailed understanding of their iron oxide and gangue mineralogy and geochemistry. The common Fe-bearing minerals (e.g., hematite, magnetite, goethite and kenomagnetite) in these deposits, as well as gangue minerals such as quartz and carbonates, are all strongly Raman active (e.g., de Faria et al., 1997). Their distinct Raman spectra enable them to be easily detected and mapped in situ in either unprepared material or samples prepared as polished blocks. In this paper, using representative examples of Australian CID ore, martite-goethite bedded iron deposit (BID) ore and banded iron formation (BIF) examined as polished blocks, we present a range of Raman spectra of the key iron ore minerals, and discuss how Raman spectroscopy can be applied to characterising iron ore mineralogy. Raman imaging micrographs, obtained using a StreamLine Plus Raman imaging system, clearly identified the main Fe-oxide and gangue components in the CID, BID and BIF samples when compared to optical micrographs. Raman analysis enabled the unequivocal identification of diamond in the CID ore as a contaminant from the polishing paste used to prepare the sample, and confirmed the presence of hematite in the BID ore in the form of martite, which can be morphologically similar to magnetite and, thus, difficult to otherwise distinguish. Image analysis of Raman mineral maps could be used to quantify mineral abundance based on the number of 'pixels

  8. Ore-Bearing Formations of the Precambrian in South China and Their Prospects

    Institute of Scientific and Technical Information of China (English)

    HE Jurui; WANG Aiguo; RUI Xingjian; LI Chunhai

    2004-01-01

    In the Precambrian System of the Yangtze and Cathaysian plates six ore-bearing formations can be identified: the Cu-Pb-Zn-bearing formations in volcanic rocks of marine facies of the Neoarchean-Paleoproterozoic, CuAu-bearing formations and Pb-Zn-bearing formations in volcanic rocks of marine facies of the Mesoproterozoic, Pb-Znbearing formations in volcaniclastic rock and carbonate rock of the Neoproterozoic, Fe-Mn-bearing formations in the volcaniclastic rock of the Neoproterozoic, and Ni-Cr-serpentine-bearing formations in ophiolite and ultrabasic rock of the Meso- and Neoproterozoic. They were mostly formed in the marginal rift valleys of the Yangtze and Cathaysian plates,where occur stratabound and stratiform ore deposits, thermal deposits and porphyry polymetallic deposits. The six regions with ore-bearing formations have good prospects for ore deposits.

  9. Seeking the mantle contribution for the formation of giant ore deposits: Contemporaneous alkaline lamproites and carbonatites in the Kalmakyr and Muruntau ore districts, Tienshan, Uzbekistan

    Science.gov (United States)

    Seltmann, Reimar; Choulet, Flavien

    2014-05-01

    various geological objects involved in both giant mineral systems. Upper Carboniferous lamproitic pipes have been recognized around the Kalmakyr ore deposit [1]; diamond-bearing lamproites occur near the Muruntau ore deposit and are contemporaneous to the Murun granite [2]. Indicator minerals of deep crustal and mantle origin have been identified within xenoliths hosted by the ore-bearing intrusions and the dikes and pipes spatially and temporally associated to the giants. SEM and CT scanning observations allow for revealing the shape and internal texture of indicator minerals and their relations (inclusion, interstitial or bulk minerals). Microanalysis (EPMA and LA-ICPMS) of indicator minerals is used to estimate the physico-chemical conditions of their formation and track the mantle involvement in magma fertilization. Results permit clues on the mantle contribution in ore formation during the late collisional to post-collisional stages of the Tienshan, and, based on complementary comparisons with other ore systems, to refine exploration models. References: [1] Yusupov, R.G.; Stanley, C.J.; Welch, M.D.; Spratt, J.; Cressey, G.; Rumsey, M.S.; Seltmann, R.; Igamberdiev, E., 2009: Mavlyanovite, Mn5Si3: a new mineral species from a lamproite diatreme, Chatkal Ridge, Uzbekistan. Mineralogical Magazine 73, 43-50. [2] Golovko, A. V.; Divaev, F. K., 2010: Ore mineralisation of the Karashokho diatreme, western Uzbekistan. Applied Earth Science 119.2: 100. [3] Dolgopolova, A.; Seltmann, R.; Armstrong, R.; Belousova, E.; Pankhurst, R.; Konopelko, D.; Koneev, R., 2013: Sr-Nd-Hf-Pb Isotope Mapping of Tien Shan in Uzbekistan. Mineralogical Magazine 77.5: 1001.

  10. Evaluating the Consequences of Edifice Instability-Related Processes in Hydrothermal Ore Genesis at Composite Volcanoes

    Science.gov (United States)

    Szakacs, A.

    2009-05-01

    Composite volcanoes intrinsically evolve toward instability, which is resolved through sudden (e.g. flank/edifice failure) or gradual (e.g. volcano-basement interaction) processes. They commonly host hydrothermal systems and related ore deposits within their edifices and shallow basement. The nature and extent of the influence instability-related processes exert on these hydrothermal systems and ore genesis are as yet poorly understood. Short-term effects are basically related to sudden depressurization of the system. The key factors determining the response of the hydrothermal system are its depth and maturity, and amount of depressurization. Deep excavation will lead to evisceration of the edifice-hosted hydrothermal system, dispersion of its volatiles in the atmosphere and incorporation of solid-phase components in the resulting debris avalanche deposit (DAD). When mature, such a system may provide DAD-hosted ore deposits. The fate of the deeper, basement-hosted hydrothermal system depends on its maturity. The evolution of an immature system will be aborted as a consequence of premature depressurization-driven boiling, and no ore-grade mineralization forms. Mature systems, however, will benefit from pressure drop and induced boiling by massive deposition of pressure-sensitive ore minerals and formation of high-grade ore. Long-range effects of edifice-failure are related to increase of the meteoric input into the hydrothermal system due to the formation of a large depression and reorganization of the surface hydrologic regime. Shift from high-T vapor-dominated regime to low-T dilute hydrothermal regime is its expected outcome. The influence of gradual release of edifice instability by volcano spreading and related phenomena on the hydrothermal system has not been studied so far. Deformation induced in both edifice and basement would result in change of fluid pathways according to the shift of local stress regimes between compressional and tensional, in turn

  11. Subduction of the Nazca Ridge and the Inca Plateau: Insights into the formation of ore deposits in Peru [rapid communication

    Science.gov (United States)

    Rosenbaum, Gideon; Giles, David; Saxon, Mark; Betts, Peter G.; Weinberg, Roberto F.; Duboz, Cecile

    2005-10-01

    A large number of ore deposits that formed in the Peruvian Andes during the Miocene (15-5 Ma) are related to the subduction of the Nazca plate beneath the South American plate. Here we show that the spatial and temporal distribution of these deposits correspond with the arrival of relatively buoyant topographic anomalies, namely the Nazca Ridge in central Peru and the now-consumed Inca Plateau in northern Peru, at the subduction zone. Plate reconstruction shows a rapid metallogenic response to the arrival of the topographic anomalies at the subduction trench. This is indicated by clusters of ore deposits situated within the proximity of the laterally migrating zones of ridge subduction. It is accordingly suggested that tectonic changes associated with impingement of the aseismic ridge into the subduction zone may trigger the formation of ore deposits in metallogenically fertile suprasubduction environments.

  12. 26 CFR 1.272-1 - Expenditures relating to disposal of coal or domestic iron ore.

    Science.gov (United States)

    2010-04-01

    ... domestic iron ore. 1.272-1 Section 1.272-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... relating to disposal of coal or domestic iron ore. (a) Introduction. Section 272 provides special treatment... sometimes referred to as a “coal royalty contract” or “iron ore royalty contract”) for the disposal of coal...

  13. Geology and geochemistry of the Macheng Algoma-type banded iron-formation, North China Craton: Constraints on mineralization events and genesis of high-grade iron ores

    Science.gov (United States)

    Wu, Huaying; Niu, Xianglong; Zhang, Lianchang; Pirajno, Franco; Luo, Huabao; Qin, Feng; Cui, Minli; Wang, Changle; Qi, Min

    2015-12-01

    The Macheng iron deposit is located in the eastern Hebei province of the North China Craton (NCC). It is hosted in Neoarchean metamorphic rocks of Baimiaozi formation in the Dantazi Group, consisting of biotite-leptynite, plagioclase-gneiss, plagioclase-amphibolite, migmatite, migmatitic granite and quartz schist. Geochemical analyses of the host biotite leptynite and plagioclase amphibolites show that their protoliths are both volcanics, inferred to be trachytic basalt and basaltic andesite, respectively. Based on the geochemical signature of the host rocks, together with geology of the iron deposit, it is inferred that the Macheng BIF is an Algoma-type iron exhalative formation, formed in an arc-related basin in the Neoarchean. Post-Archean Australian Shale (PAAS)-normalized rare earth elements (REEs) plus yttrium (Y) concentrations of different BIF ores with gneissic, striated and banded structure in the Macheng deposit, show similar patterns with depletions in light rare earth elements (LREEs) and middle rare earth elements (MREEs) relative to heavy rare earth elements (HREEs) and with apparently positive La, Y and Eu anomalies. Y/Ho ratios of the gneissic, striated and banded BIF ores vary from 37 to 56. These geochemical features of the BIF ores reveal their affinity with the sea water and the presence of a high-temperature hydrothermal component, indicating that both the seawater and high temperature hydrothermal fluids derived from alteration of oceanic basalts and komatiites may contribute to formation of the Macheng BIF. Geological, mineralogical and geochemical studies of the Macheng deposit recognized two kinds of high-grade iron ores. One is massive oxidized high-grade ore (Fe2O3T = 74.37-86.20 wt.%), mainly consisting of hematite with some magnetite, which shows geochemical characteristics of the gneissic, striated and banded BIF ores. The other type is magnetite high-grade ore, also massive and consisting of magnetite, with distinct characteristics

  14. Utilization of Polyethylene Waste and Polypropylene Wastes for Formation of Fine Copper Ore Concentrates

    Science.gov (United States)

    Szyszka, Danuta; Więckowska, Jadwiga

    2016-10-01

    The possibilities for utilization of polyethylene waste and polypropylene waste as a binding material for formation of fine grain of copper ore concentrate in Hake Rheomix were examined. The optimum parameters of the formation processes were established. Strength, thermal and microscopic properties the products obtained were determined.

  15. Formation of Strata—bound Ore Deposits in China:Studies on Fluid Inclusions

    Institute of Scientific and Technical Information of China (English)

    卢焕章; 刘从强

    1990-01-01

    Fluid inclusion studies were made on the basis of the geological data on the strata-bound ore de-posits of China including those of Pb,Zn,Au,Ag,Sb,U,Hg,W,quartz-crystal and sparry-calcite.An attempt was made to approach the model of formation for each type of ore depos-its by considering the material sources,the migration of fluids and the conditions of mineralization.It is found that ore-forming fluids (especially H2O)originate as heated underground water reacts with the wallrocks and dissolves Na+,Ca2+,K+,Cl+,HCl- and Mg2+ .The ore fluids are mainly of NaCl-Ca-HCO3-H2O system with salinities ranging from 4to 14wt.%.NaCl equivalent and densities ranging from 0.9 to 1.0g/cm3.It may be concluded that the deposits were formed at temperatures ranging from 150 to 250℃ under pressures from 300 to 1000 bars.Ore deposition may have been controlled by temperature and pressure or by the mixing among different fluids.

  16. Study on the Physical and Chemical Conditions of Ore Formation of Hetai Ductile Shear Zone-Hosted Gold Deposit and Discovery of Melt Inclusions

    Institute of Scientific and Technical Information of China (English)

    李兆麟; 翟伟; 李文; 石贵勇; 文拥军

    2002-01-01

    The Hetai ductile shear zone-hosted gold deposit occurs in the deep-seated fault mylonite zone of the Sinian-Silurian metamorphic rock series. In this study there have been discovered melt inclusions, fluid-melt inclusions and organic inclusions in ore-bearing quartz veins of the ore deposit and mylonite for the first time. The homogenization temperatures of the various types of inclusions are 160℃, 180 - 350℃, 530℃ and 870℃ for organic inclusions, liquid inclusions, two-phase immiscible liquid inclusions and melt inclusions, respectively. Ore fluid is categorized as the neutral to basic K+ -Ca2+ -Mg2+ -Na+ - SO2- 4-HCO3-Cl- system. The contents of trace gases follow a descending order of H2O>CO2>CH4>(or < ) H2>CO>C2H2>C2I-I6>O2>N2.The concentrations of K , Ca2 + ,SO2-4,HCO3-,Cl- H2O and C2H2 in fluid inclusions are related to the contents of gold and the Au/Ag ratios in ores from different levels of the gold deposit. This is significant for deep ore prospecting in the region. Daughter minerals in melt inclusions were analyzed using SEM. Quartz, orthoclase, wollastonite and other silicate minerals were identified. They were formed in different mineral assemblages.This analysis further proves the existence of melt inclusions in ore veins. Sedimentary metamorphic rocks could form silicate melts during metamorphic anatexis and dynamic metamorphism, which possess melt-solution characteristics. Ore formation is related to the multi-stage forming process of silicate melt and fluid.

  17. Ore-bearing Formations and Mineral Resource Prospects of the Peripheral Areas of the Tarim Block

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The tectonic development of the Tarim block has experienced four stages, i. e. Earth's core accretion and block formation in the Precambrian, margin splitting, opening-closing and piecing up in the Early Palaeozoic, rift formation and plate unification in the Late Palaeozoic, and basin-mountain coupling and landform shaping in the Meso-Cenozoic, forming six ore-bearing formations and ore deposits of various genetic types in the Tianshan Mountains, Kunlun Mountains and Altun Mountains. In the peripheral areas of Tarim there are four giant intercontinental metallogenic belts passing through, the Central Tianshan and southwestern Tianshan belts in the former USSR and the Qinling-Qilian-Kunlun and Palaeo-Tethys belts in China. According to the macro-analysis on the nearly one thousand known deposits (occurrences) and geophysical-geochemical anomalies, and the information from reconnaissance in some areas, the region has very good prospects for mineral resources. Some of the metallogenic belts may well become the reserve bases for exploration of mineral resources in China.

  18. Genesis and formation conditions of deposits in the unique Strel'tsovka Molybdenum-Uranium ore field: New mineralogical, geochemical, and physicochemical evidence

    Science.gov (United States)

    Aleshin, A. P.; Velichkin, V. I.; Krylova, T. L.

    2007-10-01

    The ambiguity of genetic interpretations of uranium ore formation at Mo-U deposits of the Strel’tsovka ore field led us to perform additional geochemical, mineralogical, and thermobarogeochemical studies. As a result, it has been established that closely related U and F were progressively gained in the Late Mesozoic volcanic rocks from the older basic volcanics (170 Ma) to the younger silicic igneous rocks (140 Ma). The Early Cretaceous postmagmatic hydrothermal epoch (140-125 Ma) is subdivided into preore, uranium ore, and first and second postore stages. The primary brannerite-pitchblende ore was formed in association with fluorite. At the first postore stage, this assemblage was replaced by a U-Si metagel, which was previously identified as coffinite. The metagel shows a wide compositional variation; its fine structure has been studied. The preore metasomatic alteration and related veined mineralization were formed under the effect of sodium (bicarbonate)-chloride solution at a temperature of 250-200°C. The uranium ore formation began with albitization and hematitization of rocks affected by supercritical fluid at 530-500°C; brannerite and pitchblende precipitated at 350-300°C. The chondrite-normalized REE patterns of pitchblende hosted in trachybasalt, trachydacite, and granite demonstrate a pronounced Sm-Nd discontinuity and a statistically significant tetrad effect of W type. These attributes were not established in REE patterns of rhyolites derived from the upper crustal magma chamber. This circumstance and a chronological gap of 5 Ma between silicic volcanism and ore formation do not allow us to suggest that uranium was derived from this magma chamber. According to the proposed model, the evolved silicic Li-F magma was a source of uranium. U4+, together with REE, was fractionated into the fluid phase as complex fluoride compounds. The uranium mineralization was deposited at a temperature barrier. It is suggested that hydromica alteration and the

  19. Tectonophysics of hydrothermal ore formation: an example of the Antei Mo-U deposit, Transbaikalia

    Science.gov (United States)

    Petrov, V. A.; Rebetsky, Yu. L.; Poluektov, V. V.; Burmistrov, A. A.

    2015-07-01

    The Antei deposit of the southeastern Transbaikalian region is one of the largest uranium mines in Russia. It is hosted by the Late Paleozoic granitic basement of the Streltsovskaya caldera and was formed as a result of Late Mesozoic tectonothermal activity. Vein and stockwork-disseminated molybdenum-uranium mineralization at this deposit is controlled by zones of intense hydrothermal alteration, cataclasis, brecciation, and intense fracturing along steeply dipping faults, which acted as conduits for mineralizing fluids and hosts to the ore bodies. The upper edge of the ore-bearing zone is located at a depth of 400 m, and its lower edge was intersected at a depth of 1300 m from the day surface. The conditions of ore localization were determined using structural-geological and petrophysical studies coupled with numerical modeling of the effects of gravitational body forces at purely elastic and postcritical elastoplastic deformational stages. The dynamics of the tectonic stress field in the rock massif was reconstructed using the results of mapping of morphogenetic and kinematic characteristics of fault and fracture systems, as well as data on petrography and mineralogy of rocks and vein-filling material. It was shown that the fault framework of the deposit was formed in four tectonic stages, three of which took place in the geologic past and one of which reflects recent geologic history. Each tectonic stage was characterized by different parameters of the tectonic stress-strain field, fault kinematics, and conditions of mineral formation. The following types of metasomatic rocks are recognized within the deposit: high-temperature K-feldspar rocks and albitites (formed during the Late Paleozoic as the primary structural elements of a granitic massif) and Late Mesozoic low-temperature preore (hydromicatized rocks), synore (hematite, albite, chlorite, and quartz) and postore (kaolinite-smectite) rocks. The following petrophysical parameters were determined for all

  20. Study on the Physical and Chemical Conditions of Ore Formation of Hetai Ductile Shear Zone—Hosted Gold Deposit and Discovery of Melt Inclusions

    Institute of Scientific and Technical Information of China (English)

    李兆麟; 翟伟; 等

    2002-01-01

    The Hetai ductile shear zone-hosted gold deposit occurs in the deep-seated falut mylonite zone of the Sinian-Silurian metamorphic rock series.In this study there have been discovered melt inclusions,fluid-melt inclusions and organic inclusions in ore-bearing ruartz veins of the ore deposit and mylonite for the first time.The homogenization temperatures of the various types of inclusions are 160℃,180-350℃,530℃and 870℃ for organic inclusions,liquid inclsions two-phase immiscible liquid inclusions and melt inclusion,respectively,Ore fluid is categoriezed as the neutral to basic K+-Ca2+-Mg2+-Na+-SO42--HCO3-Cl- system.The contents of trace gases follow a descending order of H2O>CO2>CH4>(orCO>C2H2>C2H6>O2>N2.The concentrations of K+,Ca2+,SO42-,HCO3-,Cl-,H2O and C2H2 in fluid inclusions are related to the contents of gold and the Au/Ag ratios in from different levels of the gold deposit.This is significant for deep ore prospecting in the region.Daughter minerals in melt inclusions were analyzed using SEM.Quartz,orthoclase,wollastonite and other silicate minerals were identified.They were formed in different mineral assemblages.This analysis further proves the existence of melt inclusions in ore veins.Sedimentary metamophic rocks could form silicate melts during metamorphic anatexis and dynamic metamorphism,which possess melt-soulution characteristics.Ore formation is related to the multi-stage forming process of silicate melt and fluid.

  1. Ore deposits in Africa and their relation to the underlying mantle

    Science.gov (United States)

    Liu, H.-S.

    1981-01-01

    African magmatism is largely related to the tensional stress regimes of the crust which are induced by the hotter upwelling mantle rocks. These mantle rocks may provide emanating forces and thermal energy for the upward movements of primary ore bodies with fluid inclusions in the tensional stress regimes of the crust. In this paper, the Goddard Earth Gravity Model is used to calculate a detailed subcrustal stress system exerted by mantle convection under Africa. The resulting system is found to be correlated with the African metallogenic provinces. Recognition of the full spectrum of ore deposits in Africa that may be associated with the hotter upwelling mantle rocks has provided an independent evidence to support the hypothesis of mantle-derived heat source for ore deposits.

  2. Formation and characterization of metallic iron grains in coal-based reduction of oolitic iron ore

    Science.gov (United States)

    Sun, Yong-sheng; Han, Yue-xin; Li, Yan-feng; Li, Yan-jun

    2017-02-01

    To reveal the formation and characteristics of metallic iron grains in coal-based reduction, oolitic iron ore was isothermally reduced in various reduction times at various reduction temperatures. The microstructure and size of the metallic iron phase were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and a Bgrimm process mineralogy analyzer. In the results, the reduced Fe separates from the ore and forms metallic iron protuberances, and then the subsequent reduced Fe diffuses to the protuberances and grows into metallic iron grains. Most of the metallic iron grains exist in the quasi-spherical shape and inlaid in the slag matrix. The cumulative frequency of metallic iron grain size is markedly influenced by both reduction time and temperature. With increasing reduction temperature and time, the grain size of metallic iron obviously increases. According to the classical grain growth equation, the growth kinetic parameters, i.e., time exponent, growth activation energy, and pre-exponential constant, are estimated to be 1.3759 ± 0.0374, 103.18 kJ·mol-1, and 922.05, respectively. Using these calculated parameters, a growth model is established to describe the growth behavior of metallic iron grains.

  3. Studies into the formation of PBDEs and PBDD/Fs in the iron ore sintering process.

    Science.gov (United States)

    Drage, D S; Aries, E; Harrad, S

    2014-07-01

    Polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) were detected in stack emissions from UK sinter plants. The sum of 36 PBDE congeners was measured at a mean concentration of 295 ng/N m(3) with a standard deviation of 96 ng/N m(3). The mean PBDD/F concentrations were 0.14 ng WHO-TEQ/m(3) (range=0.03-0.39). PBDD/F emission concentrations were approximately ten times lower than their PCDD/F homologues. To understand the possible formation mechanisms of brominated organic species in iron ore sintering, both full-scale and laboratory experiments using an experimental sintering process were carried out. A complete PBDE mass balance was undertaken for a full scale sinter plant showing that PBDEs were already present in the raw materials such as iron ores and coke breeze and that a significant proportion of the PBDE inputs were actually destroyed during the process. A number of controlled experiments were conducted using a laboratory-scale sintering apparatus (sinter pot). These were designed to investigate: (a) mass balance of PBDEs during sintering, (b) the relationship between the availability of bromide (as KBr) and PBDE emissions, and (c) the influence of the availability of both bromide and PBDEs on PBDD/F formation. As observed in the full scale plant, the PBDEs already present in the raw materials were mostly destroyed during the process (79-96%) for all sinter pot experiments. Increasing amounts of KBr in the raw sinter mix did not result in a significant increase in PBDE formation suggesting that there was no PBDE formation in sintering via de novo synthesis. No relationship was observed between PBDE inputs and PBDD/F emissions indicating that PBDEs did not act as precursors for PBDD/Fs formation. Finally, PBDD/F formation was enhanced substantially with increasing amounts of KBr suggesting that their formation mechanism was similar to that of PCDD/Fs via de novo synthesis. Copyright © 2014 Elsevier B.V. All rights

  4. Evolution of ore deposits on terrestrial planets

    Science.gov (United States)

    Burns, R. G.

    1991-01-01

    Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars

  5. Evolution of ore deposits on terrestrial planets

    Science.gov (United States)

    Burns, R. G.

    1991-01-01

    Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars

  6. Influences of ore formation on biomarkers in the Kupferschiefer from the Lubin mine, Poland

    Institute of Scientific and Technical Information of China (English)

    SUN Yuzhuang; CHEN Jianping; LIN Mingyue; MENG Zhiqiang; ZHANG Hongjian

    2005-01-01

    Molecular biomarkers are the important maturity parameters for sedimentary organic matter. They have also been widely used for determining the maturity of organic matter in ore deposits. However, during the study of organic matter in the Kupferschiefer from the Lubin mine, it had been found that the biomarkers were influenced by sulfide formation. In order to probe into the degree of influence on biomarkers, seven samples collected from a Kupferschiefer section from the Lubin mine were analyzed by various geochemical methods. The results indicated that in the samples with higher copper contents, the values of biomarkers are lower than in the samples with lower copper contents. In highly mineralized samples, hydrogen donation for thermochemical sulfate reduction (TSR) occurred in alkylated phenanthrenes and naphthalenes, leading to the decrease of 12 biomarker parameters during the Kupferschiefer mineralization.

  7. Kinetics of reaction of roasting of soda ash and ilmenite ore concentrate for formation of sodium titanates

    Directory of Open Access Journals (Sweden)

    Nafeaa I.A.

    2015-01-01

    Full Text Available Alkaline metals and hydrogen titanates are of great interest for possible applications. The soda ash and Rosetta ilmenite ore concentrate briquette were investigated. The kinetic of formation of sodium titanate was studied in the temperature range 700°C to 900°C.

  8. Formation and mitigation of PCDD/Fs in iron ore sintering.

    Science.gov (United States)

    Ooi, Tze Chean; Lu, Liming

    2011-10-01

    The sintering of iron ore is presently a significant industrial source of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) worldwide owing to the fundamental requirement of the operation of a high temperature process to pre-treat fines and to recycle plant by-products arising from the integrated iron and steelworks. The process is a noteworthy contributor of PCDD/F indirectly due to decreasing PCDD/F releases from municipal solid waste incineration. Commonly PCDD/F formation from the process is associated with the addition of oily mill scales although raw material containing a combination of C, Cl and specific metal catalyst has been shown to drastically increase PCDD/F formation in the process. The degenerate graphitic structure of carbon present in coke fuel and soot formed and the chemistry of catalytic metals and Cl are important factors. A review on PCDD/F emission in this process has been carried out, including examination of its formation mechanism, congener distribution, contributing factors and mitigation strategies, with emphasis on the use of inhibiting compound to achieve suppression. A detailed analysis of the de novo and precursor theories of formation and the contributing factor is given since the subject of PCDD/F formation is still controversial. The de novo formation pathway identified in sinter plants and controlled studies performed in the laboratory as well as at pilot-scale are discussed; where appropriate, a comparison is drawn between sintering and other thermal processes emitting PCDD/Fs. Summary of the latest developments in PCDD/F downstream abatement strategies presently employed in full scale industrial plants is provided. Potential inhibiting compounds are discussed in terms of their mode of action and merits under sintering conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Temporal Evolution of Volcanic and Plutonic Magmas Related to Porphyry Copper Ores Based on Zircon Geochemistry

    Science.gov (United States)

    Dilles, J. H.; Lee, R. G.; Wooden, J. L.; Koleszar, A. M.

    2015-12-01

    Porphyry Cu (Mo-Au) and epithermal Au-Ag ores are globally associated with shallow hydrous, strongly oxidized, and sulfur-rich arc intrusions. In many localities, long-lived magmatism includes evolution from early andesitic volcanic (v) and plutonic (p) rocks to later dacitic or rhyolitic compositions dominated by plutons. We compare zircon compositions from three igneous suites with different time spans: Yerington, USA (1 m.y., p>v), El Salvador, Chile (4 m.y., p>v), and Yanacocha, Peru (6 m.y., v>p). At Yerington granite dikes and ores formed in one event, at ES in 2 to 3 events spanning 3 m.y., and at Yanacocha in 6 events spanning 5 m.y. At both ES and Yanacocha, high-Al amphiboles likely crystallized at high temperature in the mid-crust and attest to deep magmas that periodically recharged the shallow chambers. At Yanacocha, these amphiboles contain anhydrite inclusions that require magmas were sulfur-rich and strongly oxidized (~NNO+2). The Ti-in-zircon geothermometer provides estimates of 920º to 620º C for zircon crystallization, and records both core to rim cooling and locally high temperature rim overgrowths. Ore-related silicic porphyries yield near-solidus crystallization temperatures of 750-650°C consistent with low zircon saturation temperatures. The latter zircons have large positive Ce/Ce* and small negative Eu/Eu*≥0.4 anomalies attesting to strongly oxidized conditions (Ballard et al., 2001), which we propose result from crystallization and SO2 loss to the magmatic-hydrothermal ore fluid (Dilles et al., 2015). The Hf, REE, Y, U, and Th contents of zircons are diverse in the magma suites, and Th/U vs Yb/Gd plots suggest a dominant role of crystal fractionation with lesser roles for both crustal contamination and mixing with high temperature deep-sourced mafic magma. Ce/Sm vs Yb/Gd plots suggest that magma REE contents at <900°C are dominated by early crystallization of hornblende and apatite, and late crystallization (~<780°C) of titanite

  10. A predictive model for the transport of copper by HCl-bearing water vapour in ore-forming magmatic-hydrothermal systems: Implications for copper porphyry ore formation

    Science.gov (United States)

    Migdisov, Art. A.; Bychkov, A. Yu.; Williams-Jones, A. E.; van Hinsberg, V. J.

    2014-03-01

    divalent copper dichloride (CuCl2). The model developed in this study was used to evaluate the solubility of chalcopyrite in HCl-bearing, low density aqueous fluids for temperatures ranging between 300 and 800 °C. This evaluation showed that, even for a relatively modest proportion of HCl (0.5 vol%), the concentration of copper in low-density fluids in equilibrium with this mineral can reach thousands of ppm at temperatures between 550 and 700 °C and fO2 conditions similar to those of porphyry copper ore-forming systems.

  11. Influence of gangue existing states in iron ores on the formation and flow of liquid phase during sintering

    Institute of Scientific and Technical Information of China (English)

    Guo-liang Zhang; Sheng-li Wu; Shao-guo Chen; Bo Su; Zhi-gang Que; Chao-gang Hou

    2014-01-01

    Gangue existing states largely affect the high-temperature characteristics of iron ores. Using a micro-sintering method and scan-ning electron microscopy, the effects of gangue content, gangue type, and gangue size on the assimilation characteristics and fluidity of liquid phase of five different iron ores were analyzed in this study. Next, the mechanism based on the reaction between gangues and sintering mate-rials was unraveled. The results show that, as the SiO2 levels increase in the iron ores, the lowest assimilation temperature (LAT) decreases, whereas the index of fluidity of liquid phase (IFL) increases. Below 1.5wt%, Al2O3 benefits the assimilation reaction, but higher concentra-tions proved detrimental. Larger quartz particles increase the SiO2 levels at the local reaction interface between the iron ore and CaO, thereby reducing the LAT. Quartz-gibbsite is more conductive to assimilation than kaolin. Quartz-gibbsite and kaolin gangues encourage the forma-tion of liquid-phase low-Al2O3-SFCA with high IFL and high-Al2O3-SFCA with low IFL, respectively.

  12. Influence of gangue existing states in iron ores on the formation and flow of liquid phase during sintering

    Science.gov (United States)

    Zhang, Guo-liang; Wu, Sheng-li; Chen, Shao-guo; Su, Bo; Que, Zhi-gang; Hou, Chao-gang

    2014-10-01

    Gangue existing states largely affect the high-temperature characteristics of iron ores. Using a micro-sintering method and scanning electron microscopy, the effects of gangue content, gangue type, and gangue size on the assimilation characteristics and fluidity of liquid phase of five different iron ores were analyzed in this study. Next, the mechanism based on the reaction between gangues and sintering materials was unraveled. The results show that, as the SiO2 levels increase in the iron ores, the lowest assimilation temperature (LAT) decreases, whereas the index of fluidity of liquid phase (IFL) increases. Below 1.5wt%, Al2O3 benefits the assimilation reaction, but higher concentrations proved detrimental. Larger quartz particles increase the SiO2 levels at the local reaction interface between the iron ore and CaO, thereby reducing the LAT. Quartz-gibbsite is more conductive to assimilation than kaolin. Quartz-gibbsite and kaolin gangues encourage the formation of liquid-phase low-Al2O3-SFCA with high IFL and high-Al2O3-SFCA with low IFL, respectively.

  13. Geochemical Features of Ore Fluid for Gold Deposits Related to Alkaline Rocks in China

    Institute of Scientific and Technical Information of China (English)

    齐金忠; 李莉

    2000-01-01

    Fluid inclusion studies of 5 gold deposits connected with alkaline rocks show that quartz separated from auriferous quartz veins contains abundant three-phase CO2-NaCl-H2O inclusions and two-phase CO2-dominated ones,measuring 5-20um in diameter,Homogenization temperatures of the fluid inclusions are mostly within the range of 150-300℃,and the salinities,mainly 0.2wt%-12 wt%(NaCl),Gold mineralizations occurred at depths of 1.4-2.8km,The most striking character of fluid composition is that among the cations,Na+ in dominant,followed by K+,Ca2+,among the anions,Cl- is slightly higher than SO42-,In the evaporate,H2O is dominant,followed by CO2,The pH values are mainly within the range of 6.5-8.5,indicating that the ore-forming solutions are alkaline in nature.The hydrogen and oxygen isotopic ratios indicate that the ore fluid is composed mainly of magmatic water.With the dropping of temperature in the ore fluid,the contents of CO2 decreased while the salinity increased.The relations between Au and other components of the ore fluid are discussed in the paper,and it is concluded that in these deposits,Chlorides,H2S,SiO2,CO2,etc.in the fluid all are involved in the migration and concentration of Au.

  14. Mechanism of unintentionally produced persistent organic pollutant formation in iron ore sintering.

    Science.gov (United States)

    Sun, Yifei; Liu, Lina; Fu, Xin; Zhu, Tianle; Buekens, Alfons; Yang, Xiaoyi; Wang, Qiang

    2016-04-05

    Effects of temperature, carbon content and copper additive on formation of chlorobenzenes (CBzs) and polychlorinated biphenyls (PCBs) in iron ore sintering were investigated. By heating simulated fly ash (SFA) at a temperature range of 250-500°C, the yield of both CBzs and PCBs presented two peaks of 637ng/g-fly ash at 350°C and 1.5×10(5)ng/g-fly ash at 450°C for CBzs, and 74ng/g-fly ash at 300°C and 53ng/g-fly ash at 500°C. Additionally, in the thermal treatment of real fly ash (RFA), yield of PCBs displayed two peak values at 350°C and 500°C, however, yield of CBzs showed only one peak at 400°C. In the thermal treatment of SFA with a carbon content range of 0-20wt% at 300°C, both CBzs and PCBs obtained the maximum productions of 883ng/g-fly ash for CBzs and 127ng/g-fly ash for PCBs at a 5wt% carbon content. Copper additives also affected chlorinated aromatic formation. The catalytic activity of different copper additives followed the orders: CuCl2∙2H2O>Cu2O>Cu>CuSO4>CuO for CBzs, and CuCl2∙2H2O>Cu2O>CuO>Cu>CuSO4 for PCBs. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Hydrodynamic modeling of magmatic-hydrothermal activity at submarine arc volcanoes, with implications for ore formation

    Science.gov (United States)

    Gruen, Gillian; Weis, Philipp; Driesner, Thomas; Heinrich, Christoph A.; de Ronde, Cornel E. J.

    2014-10-01

    Subduction-related magmas have higher volatile contents than mid-ocean ridge basalts, which affects the dynamics of associated submarine hydrothermal systems. Interaction of saline magmatic fluids with convecting seawater may enhance ore metal deposition near the seafloor, making active submarine arcs a preferred modern analogue for understanding ancient massive sulfide deposits. We have constructed a quantitative hydrological model for sub-seafloor fluid flow based on observations at Brothers volcano, southern Kermadec arc, New Zealand. Numerical simulations of multi-phase hydrosaline fluid flow were performed on a two-dimensional cross-section cutting through the NW Caldera and the Upper Cone sites, two regions of active venting at the Brothers volcanic edifice, with the former hosting sulfide mineralization. Our aim is to explore the flow paths of saline magmatic fluids released from a crystallizing magma body at depth and their interaction with seawater circulating through the crust. The model includes a 3×2 km sized magma chamber emplaced at ∼2.5 km beneath the seafloor connected to the permeable cone via a ∼200 m wide feeder dike. During the simulation, a magmatic fluid was temporarily injected from the top of the cooling magma chamber into the overlying convection system, assuming hydrostatic conditions and a static permeability distribution. The simulations predict a succession of hydrologic regimes in the subsurface of Brothers volcano, which can explain some of the present-day hydrothermal observations. We find that sub-seafloor phase separation, inferred from observed vent fluid salinities, and the temperatures of venting at Brothers volcano can only be achieved by input of a saline magmatic fluid at depth, consistent with chemical and isotopic data. In general, our simulations show that the transport of heat, water, and salt from magmatic and seawater sources is partly decoupled. Expulsion of magmatic heat and volatiles occurs within the first few

  16. Skarn and ore formation at Seriphos, Greece as a consequence of granodiorite intrusion

    NARCIS (Netherlands)

    Salemink, J.

    1985-01-01

    On the island of Seriphos, Greece, the shallow intrusion of a granodiorite pluton into a series of previously regionally metamorphosed gneisses, marbles and marble-bearing schists produced a contact metamorphic aureole and extensive deposits of Ca-Fe-Mg skarns and Fe-ores. Structural and petrologica

  17. Skarn and ore formation at Seriphos, Greece as a consequence of granodiorite intrusion

    NARCIS (Netherlands)

    Salemink, J.

    1985-01-01

    On the island of Seriphos, Greece, the shallow intrusion of a granodiorite pluton into a series of previously regionally metamorphosed gneisses, marbles and marble-bearing schists produced a contact metamorphic aureole and extensive deposits of Ca-Fe-Mg skarns and Fe-ores. Structural and petrologica

  18. Neotethyan rifting-related ore occurrences: study of an accretionary mélange complex (Darnó Unit, NE Hungary)

    Science.gov (United States)

    Kiss, Gabriella B.; Oláh, Erika; Zaccarini, Federica; Szakáll, Sándor

    2016-02-01

    The geology of the NE Hungarian Darnó Unit is rather complicated, as it is composed mostly of a Jurassic accretionary mélange complex, according to the most recent investigations. The magmatic and sedimentary rock blocks of the mélange represent products of different evolutionary stages of the Neotethys; including Permian and Triassic sedimentary rocks of marine rifting related origin, Triassic pillow basalt of advanced rifting related origin and Jurassic pillow basalt originated in back-arc-basin environment. This small unit contains a copper-gold occurrence in the Permian marly-clayey limestone, an iron enrichment in the Triassic sedimentary succession, a copper-silver ore occurrence in Triassic pillow basalts and a copper ore indication, occurring both in the Triassic and Jurassic pillow basalts. The present study deals with the Cu(-Ag) occurrence in the Triassic basalt and the Fe occurrence in the Triassic sedimentary succession. The former shows significant similarities with the Michigan-type mineralizations, while the latter has typical characteristics of the Fe-SEDEX deposits. All the above localities fit well into the new geological model of the investigated area. The mineralizations represent the different evolutionary stages of the Neotethyan rifting and an epigenetic, Alpine metamorphism-related process and their recent, spatially close position is the result of the accretionary mélange formation. Thus, the Darnó Unit represents a perfect natural laboratory for studying and understanding the characteristic features of several different rifting related ore forming processes.

  19. Seismic hazard related to rate of face advance in Lubin copper ore mine

    Directory of Open Access Journals (Sweden)

    Anna Gogolewska

    2013-09-01

    Full Text Available Seismic hazard was depicted by means of seismic activity. The rate of face advance was defined as the output-energy ratio (J/kg and as the distance in meters, which the face overcomes in a given time (for example six months. Seismic activity was analyzed in relation to such the rates of face advance. The analyses were performed for two mining districts (G-7 and G-8 of Lubin copper ore mine. The period of 2008-2009 years was taken into account. In both mining districts the outputenergy ratio did not show any strict connection between the rate of face advance and seismic activity. Whilst seismic hazard increased with increasing rate of face advance defined as the distance between two sequential positions of face in most panels of the two mining districts.

  20. Relation between ore-forming hydrothermal systems and extensional deformation in the Solea graben spreading center, Troodos ophiolite, Cyprus

    Science.gov (United States)

    Bettison-Varga, Lori; Varga, Robert J.; Schiffman, Peter

    1992-11-01

    Field relations indicate that high-temperature hydrothermal circulation and accumulation of massive sulfide deposits within the Solea graben of the Troodos ophiolite, Cyprus, followed extreme crustal attenuation. Zones of pervasive, massive epidosite strike parallel to the axis of the Solea graben and to the strike of extensional normal faults. Initial fluid flow, evidenced by preferential epidotization in weakly altered areas surrounding massively altered regions, was focused along joints, microfractures, and (now) low-angle normal-fault zones related to graben formation. Permeability within the sheeted-dike section was enhanced by brittle deformation related to extensional structures as well as through volume reduction inherent in the diabase to epidosite mineralogic phase transformations. Intrusion of high-level gabbros into epidosite zones occurred both before and after significant amagmatic tectonic extension. Structural control on epidotization suggests that intrusion of late stocks into attenuated and highly deformed crust is necessary to drive the vigorous hydrothermal circulation that produced the epidosites and ore bodies of the Solea graben. A similar sequence of events is more likely to occur in the modern oceans along ridge crests with ephemeral magmatism, especially at intermediate- to slow-spreading ridges near transform faults.

  1. Geochemical and Nd isotopic constraints on provenance and depositional setting of the Shihuiding Formation in the Shilu Fe-Co-Cu ore district, Hainan Province, South China

    Science.gov (United States)

    Yu, Liangliang; Zou, Shaohao; Cai, Jianxin; Xu, Deru; Zou, Fenghui; Wang, Zhilin; Wu, Chuanjun; Liu, Meng

    2016-04-01

    The Shihuiding Formation, a subordinate succession hosting the Fe-Co-Cu ores, is a suite of Neoproterozoic terrigenous clastic rocks occurring in the Shilu Fe-Co-Cu ore district of the Hainan Island, South China. Integrated petrographical, geochemical, and Nd isotopic analyses have been carried out on 23 sandstone specimens of the Shihuiding Formation in order to understand their provenance and the tectonic setting of their deposition. The samples can be divided into two groups, quartzose sandstones (13 samples) and ferruginous sandstones (10 samples). The ferruginous sandstones have average SiO2 and Fetotal contents of 77.23 wt.% and 18.09 wt.%, respectively, and this contrasts with the higher average SiO2 (94.04 wt.%) and lower Fetotal (2.67 wt.%) contents of the quartzose sandstones. The bivariant Th/Sc and Zr/Sc ratios indicate a predominantly recycled sedimentary provenance, and the low to medium degrees of weathering are commonly indicated by an average chemical index of maturity (CIM) of 81 and an average chemical index of alteration (CIA) of 68. The Shihuiding Formation sandstones have REE contents of 21-249 ppm, with LREE/HREE = 9.18 and δEu = 0.67. The εNd (970 Ma) values of -5.7 to -3.4, and model (TDM) ages of 2099-1773 Ma are compatible with a source mainly from the Paleo- to Mesoproterozoic Baoban Group, a suite of metamorphosed sedimentary rocks intruded by ca. 1450 Ma granites. Quantitative provenance modeling indicates that the Shihuiding Formation sandstones are best modeled with a mixture of 29% plagioclase-amphibole gneiss (29 P), 38% quartz-muscovite schist (38 Q), and 33% granite (33 G) detritus. Mixing the εNd values of the sandstones, calculated at 970 Ma, indicates that the sediment received 22-47% (average 34%) of its detritus from the Baoban Group quartz-muscovite schists. Components from hydrothermal fluids may also have been involved during deposition of the Shihuiding Formation sandstones, as revealed by a bivariant Al/(Al + Fe + Mn

  2. Multiple Sulfate Isotopic Evidence on the Formation of Oxide Copper Ore at Spence, Atacama Desert, Northern Chile

    Science.gov (United States)

    Sun, T.; Bao, H.; Reich, M.; Palacios, C.

    2007-12-01

    In the Atacama Desert of northern Chile, one of the world's richest metallogenic provinces, porphyry copper deposits are characterized by the unique occurrence of atacamite in their oxidized zones. The origin and formation of the oxide zone of these copper deposits is, however, controversial. It was proposed that Cl-rich deep formation water pumping-up events along faults by earthquakes, after onset of the hyperaridity, were required (Cameron et al., 2007). Their model would imply that supplies of saline deep formation water from fractures to the surface should have left behind a homogeneous or fracture-controlled salt profile from surface down to the oxide zone. While no excluding the deep formation water model in other deposit, here we propose that, in our sampling region, the alternative saline source, which is critical for atacamite formation, could be locally evaporated groundwater, Cl-rich salts leached from arid surface by meteoric water, or brines from eastern salar basins at a time when the climate in northern Chile was changing from arid to hyperarid. At this climate transition, arid- requiring minerals such as atacamite in the oxide zone were formed and, more importantly, preserved upon evaporation beneath the surface alluvial deposits. Since salt accumulation at the surface remain active during hyperarid condition, our model would predict that water-soluble salt profile from surface to the oxide zone should have a characteristic pattern: salts with an atmospheric component on the surface gradually transitioning to salts of the oxide ore zone on the bottom and a mixing zone in between. To test these two alternative models, we focus on sulfate salts, one of the common water-soluble salts in arid environments. An added advantage is that sulfate accumulated on desert surface has a secondary atmospheric component that bears a unique triple oxygen isotope signature, easily distinguishable from sulfate formed by the oxidation of sulfide minerals at the oxide

  3. Evaluation of Social Performance and Related Factors in Iranian Central Iron Ore company workers

    Directory of Open Access Journals (Sweden)

    Gholamhossein Halvani

    2013-01-01

    Full Text Available Introduction: Psychological and social health is the main problems of workers population, which can increase productivity at work and physical and mental health and provide or decline in these aspects. Materials and Methods: this study was descriptive and crosses - sectional and has been performed on 388 Iranian central iron ore company workers. The tool of study was standard GHQ-28 question are that has been measured under social performance scale. Results: 49.3 and 49 percent of the people have favorable and average score from the state of the social function condition and 1.8 percent of people have severe social dysfunction and besides the employees have less work experienced that have more social dysfunction and there is a relationship between the P = 0.026. With satisfaction with the status of social dysfunction (P = 0 and with the consent of the income (P = 0 there is significant relationship. Conclusion: In this study, a significant percentage of mineworkers were not in good condition from health, social functioning. It reveals the importance of addressing health issues and vulnerable working class, Intervention studies conducted by employers to improve job satisfaction and increased income and received social support from him, can increase the health indicators related to the body and mind.

  4. Textural, compositional, and sulfur isotope variations of sulfide minerals in the Red Dog Zn-Pb-Ag deposits, Brooks Range, Alaska: Implications for Ore Formation

    Science.gov (United States)

    Kelley, K.D.; Leach, D.L.; Johnson, C.A.; Clark, J.L.; Fayek, M.; Slack, J.F.; Anderson, V.M.; Ayuso, R.A.; Ridley, W.I.

    2004-01-01

    The Red Dog Zn-Pb deposits are hosted in organic-rich mudstone and shale of the Mississippian Kuna Formation. A complex mineralization history is defined by four sphalerite types or stages: (1) early brown sphalerite, (2) yellow-brown sphalerite, (3) red-brown sphalerite, and (4) late tan sphalerite. Stages 2 and 3 constitute the main ore-forming event and are volumetrically the most important. Sulfides in stages 1 and 2 were deposited with barite, whereas stage 3 largely replaces barite. Distinct chemical differences exist among the different stages of sphalerite. From early brown sphalerite to later yellow-brown sphalerite and red-brown sphalerite, Fe and Co content generally increase and Mn and Tl content generally decrease. Early brown sphalerite contains no more than 1.9 wt percent Fe and 63 ppm Co, with high Mn (up to 37 ppm) and Tl (126 ppm), whereas yellow-brown sphalerite and red-brown sphalerite contain high Fe (up to 7.3 wt %) and Co (up to 382 ppm), and low Mn (subsea-floor hydrothermal recrystallization and coarsening of preexisting barite; (3) open-space deposition of barite, red-brown sphalerite and other sulfides in veins and coeval replacement of barite; and (4) postore sulfide deposition, including the formation of late tan sphalerite breccias. Stage 1 mineralization took place in a low-temperature environment where fluids rich in Ba mixed with pore water or water-column sulfate to form barite, and metals combined with H2S derived from bacterial sulfate reduction to form sulfides. Higher temperatures and salinities and relatively oxidized ore-stage fluids (stages 2 and 3) compared with stage 1 were probably important controls on the abundances and relative amounts of metals in the fluids and the resulting sulfide chemistry. Textural observations and isotopic data show that preexisting barite was reductively dissolved, providing a source of H2S for sulfide mineral formation. In stage 3, the continued flow of hydrothermal fluids caused thermal

  5. Authigenetic K—feldspars and Their Relations to Sn—polymetallic Mineralization in the Dachang Ore Field

    Institute of Scientific and Technical Information of China (English)

    潘家华; G.C.AMSTUTZ

    1993-01-01

    Sn-polymetallic ores at Dachang,Guangxi Autonomous Region,China,are hosted in Middle-Upper Devonian reef limestones,siliceous rocks,banded and lenticular limestones,etc.Two types of orebodies can be distinguished according to their telations to the bedding:one is distributed along the bedding and the.other cuts across the bedding.Sn and sulfide orebodies associated with K-feldspare are mostly characterized by laminated ore structure. Microscopic examinations of K-feldspar-bearing rocks,in conjunction with X-ray diffraction,chemical composiion and cathodoluminescence data for K-feldspars,as well as their telations to mineralization,the authors consider that the K-feldspare are of authigenic origin,subordinate to the epigenetic stage of diagenesis,They resulted from the reaction of mixed,deep-seated,circulating underground hot waters rich in K,Al and Si with argillaceous carbonates during the Indo nesian orogenic movement.It is suggested more attention should be paid to the effect of authigenic K-feldspars on Sn mineralization.In the meantime the event related to circulating underground hot waters should also be taken into account so as to provide new clues to blind ore prospecting.

  6. Detailed mineral and chemical relations in two uranium-vanadium ores

    Science.gov (United States)

    Garrels, Robert M.; Larsen, E. S.; Pommer, A.M.; Coleman, R.G.

    1956-01-01

    Channel samples from two mines on the Colorado Plateau have been studied in detail both mineralogically and chemically. A channel sample from the Mineral Joe No. 1 mine, Montrose County, Colo., extends from unmineralized rock on one side, through a zone of variable mineralization, into only weakly mineralized rock. The unmineralized rock is a fairly clean quartz sand cemented with gypsum and contains only minor amounts of clay minerals. One boundary between unmineralized and mineralized rock is quite sharo and is nearly at right angles to the bedding. Vanadium clay minerals, chiefly mixed layered mica-montmorillonite and chlorite-monmorillonite, are abundant throughout the mineralized zone. Except in the dark "eye" of the channel sample, the vanadium clay minerals are accompanied by hewettite, carnotite, tyuyamunite, and probably unidentified vanadates. In the dark "eye," paramontroseite, pyrite, and marcasite are abundant, and bordered on each side by a zone containing abundant corvusite. No recognizable uranium minerals were seen in the paramontroseite zone although uranium is abundant there. Coaly material is recognizable throughout all of the channel but is most abundant in and near the dark "eye." Detailed chemical studies show a general increase in Fe, Al, U, and V, and a decrease in SO4 toward the "eye" of the channel. Reducing capacity studies indicate that V(IV) and Fe(II) are present in the clay mineral throughout the channel, but only in and near the "eye" are other V(IV) minerals present (paramontroseite and corvusite). The uranium is sexivalent, although its state of combination is conjectural where it is associated with paramontroseite. Where the ore boundary is sharp, the boundary of introduced trace elements is equally sharp. Textural and chemical relations leave no doubt that the "eye: is a partially oxidized remnant of a former lower-valence ore, and the remainder of the channel is a much more fully oxidized remnant. A channel sample from the

  7. Micro-scale characterization of iron ores from a banded iron formation in Yishui county, western Shandong province of North China Craton

    Science.gov (United States)

    Moon, I.; Lee, I.; Yang, X.

    2016-12-01

    Banded iron formations (BIFs) are widely distributed in North China Craton (NCC). Yishui BIF is located in Yishui county, western Shandong Province of NCC and is categorized as Algoma-type. The origin of iron and silica of BIFs in this region have been studied extensively for decades. The trace elemental concentrations of magnetite and hematite in iron ores from Yishui BIF are focused in this study to better understand the origins of BIF. To discuss micro-structural signatures of iron ores, X-ray diffraction (XRD), Raman spectrometer, electron microprobe (EPMA) and laser ablation inductively-coupled plasma mass spectrometer (LA-ICP-MS) were utilized. Overall geochemical data represents abundance of trace elements, oxygen fugacity (fO2) condition during the formation of iron oxides, depositional environment of Yishui BIF, implying the involvement of volcanic eruption and hydrothermal exhalation during the chemical deposition.

  8. The world-class Jinding Zn-Pb deposit: ore formation in an evaporite dome, Lanping Basin, Yunnan, China

    Science.gov (United States)

    Leach, David L.; Song, Yu-Cai; Hou, Zeng-Qian

    2017-03-01

    The Jinding Zn-Pb sediment-hosted deposit in western Yunnan, China, is the fourth largest Zn deposit in Asia. Based on field observations of the ore textures, breccias, and the sandstone host rocks, the ores formed in a dome that was created by the diapiric migration of evaporites in the Lanping Basin during Paleogene deformation and thrust loading. Most of the ore occurs in sandstones that are interpreted to be a former evaporite glacier containing a mélange of extruded diapiric material, including breccias, fluidized sand, and evaporites that mixed with sediment from a fluvial sandstone system. A pre-ore hydrocarbon and reduced sulfur reservoir formed in the evaporite glacier that became the chemical sink for Zn and Pb in a crustal-derived metalliferous fluid. In stark contrast to previous models, the Jinding deposit does not define a unique class of ore deposits; rather, it should be classified as MVT sub-type hosted in a diapiric environment. Given that Jinding is a world-class ore body, this new interpretation elevates the exploration potential for Zn-Pb deposit in other diapir regions in the world.

  9. The world-class Jinding Zn-Pb deposit: ore formation in an evaporite dome, Lanping Basin, Yunnan, China

    Science.gov (United States)

    Leach, David L.; Song, Yu-Cai; Hou, Zeng-Qian

    2016-07-01

    The Jinding Zn-Pb sediment-hosted deposit in western Yunnan, China, is the fourth largest Zn deposit in Asia. Based on field observations of the ore textures, breccias, and the sandstone host rocks, the ores formed in a dome that was created by the diapiric migration of evaporites in the Lanping Basin during Paleogene deformation and thrust loading. Most of the ore occurs in sandstones that are interpreted to be a former evaporite glacier containing a mélange of extruded diapiric material, including breccias, fluidized sand, and evaporites that mixed with sediment from a fluvial sandstone system. A pre-ore hydrocarbon and reduced sulfur reservoir formed in the evaporite glacier that became the chemical sink for Zn and Pb in a crustal-derived metalliferous fluid. In stark contrast to previous models, the Jinding deposit does not define a unique class of ore deposits; rather, it should be classified as MVT sub-type hosted in a diapiric environment. Given that Jinding is a world-class ore body, this new interpretation elevates the exploration potential for Zn-Pb deposit in other diapir regions in the world.

  10. Alligator Rivers Analogue project. Geochemical modelling of secondary uranium ore formation. Final Report - Volume 11

    Energy Technology Data Exchange (ETDEWEB)

    Sverjensky, D. [The John Hopkins Univ, Dept of Earth and Planetary Sciences, Baltimore (United States); Bennett, D.G.; Read, D. [W.S. Atkins Science and Technology, Epsom Surrey, (United Kingdom)

    1992-12-31

    The purpose of the present study was to establish how the uranyl phosphate zone at the Koongarra site was formed. The overall approach taken in the present study employed theoretical chemical mass transfer calculations and models that permit investigation and reconstruction of the kinds of waters that could produce the uranyl phosphate zone. These calculations have used the geological and mineralogical data for the Koongarra weathered zone (Volumes 2, 8, and 9 of this series), to constrain the initial compositions and reactions undergone by groundwater during the formation of the uranyl phosphate zone. In carrying out these calculations the present-day analyses of Koongarra waters are used only as a guide to the possible initial composition of the fluids associated with the formation of the phosphate zone. Aqueous speciation, saturation state and chemical mass transfer calculations were carried out using the computer programs EQ3NR and EQ6 (Wolery, 1983; Wolery et al., 1984) and a thermodynamic database generated at The Johns Hopkins University over the last eight years which is tabulated in the Appendix 1 to Volume 12 of this series. Despite uncertainties in the thermodynamic characterisation of species, all the above calculations suggest that the uranyl phosphate zone at Koongarra has not formed from present-day groundwaters (Volume 12 of this series). The present-day groundwaters in the weathered zone (eg. at 13 m depth) appear to be undersaturated with respect to saleeite. Furthermore, as present-day groundwaters descend below the water table they rapidly lose their atmospheric oxygen imprint, as is typical of most groundwaters, and become even more reducing in character. Under these circumstances, the groundwaters become more undersaturated with respect to saleeite than the shallow groundwaters. Because much of the phosphate zone is currently below the water table, under saturated zone conditions, it is suggested in the present study that the uranyl phosphate

  11. An Overview of Process Monitoring Related to the Production of Uranium Ore Concentrate

    Energy Technology Data Exchange (ETDEWEB)

    McGinnis, Brent [Innovative Solutions Unlimited, LLC

    2014-04-01

    Uranium ore concentrate (UOC) in various chemical forms, is a high-value commodity in the commercial nuclear market, is a potential target for illicit acquisition, by both State and non-State actors. With the global expansion of uranium production capacity, control of UOC is emerging as a potentially weak link in the nuclear supply chain. Its protection, control and management thus pose a key challenge for the international community, including States, regulatory authorities and industry. This report evaluates current process monitoring practice and makes recommendations for utilization of existing or new techniques for managing the inventory and tracking this material.

  12. ON SOME KEY GEOLOGICAL PROBLEMS RELATED TO THE LINGLONG-JIAOJIA ORE-CENTRALIZED DISTRICT IN SHANDONG PROVINCE, CHINA

    Institute of Scientific and Technical Information of China (English)

    WANG Jincao; XIA Bin; TANG Jingru

    2003-01-01

    The Lingtong-Jiaojia ore-centralized district is controlled by the tectonic stress field characterized bY the combination of extension and strike-slip, and the dip, dip angle, pitch and pitch angle of the ore bodies are all constrained by the dynamic conditions of the tectonics. The metallotectonic series for the ore-centralized district belong to the type of a combination of extension and strike-slip and can be subdivided into four sub-series. The ore-forming process in the brittle regime can be disintegrated into two stages, i.e., the embryonic fracture stage and the megascopic fracture stage, and ore-forming process is rather common in the ore-centralized district at the former stage. Moreover, several key structural patterns and their features were discussed and a preliminary assessment about the ore-forming prospect in this district was made in the paper.

  13. Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska

    Science.gov (United States)

    Taylor, Ryan D.; Graham, Garth E.; Anderson, Eric D.; Selby, David

    2014-01-01

    This report presents isotopic age data from mineralized granitic plutons in an area of the Alaska Range located approximately 200 kilometers to the west-northwest of Anchorage in southwestern Alaska. Uranium-lead isotopic data and trace element concentrations of zircons were determined for 12 samples encompassing eight plutonic bodies ranging in age from approximately 76 to 57.4 millions of years ago (Ma). Additionally, a rhenium-osmium age of molybdenite from the Miss Molly molybdenum occurrence is reported (approx. 59 Ma). All of the granitic plutons in this study host gold-, copper-, and (or) molybdenum-rich prospects. These new ages modify previous interpretations regarding the age of magmatic activity and mineralization within the study area. The new ages show that the majority of the gold-quartz vein-hosting plutons examined in this study formed in the Late Cretaceous. Further work is necessary to establish the ages of ore-mineral deposition in these deposits.

  14. Phase Equilibria Constraints on Relations of Ore-bearing Intrusionswith Flood Basalts in the Panxi Region, Southwestern China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhaochong; HAO Yanli; AI Yu; LI Ying; ZHAO Li

    2009-01-01

    There are two types of temporally and spatially associated intrusions within the Emeishan large igneous province (LIP); namely, small uitramafic subvolcanic sills that host magmatic Cu-Ni-Platinum Group Element (PGE)-bearing sulfide deposits and large mafic layered intrusions that host giant Ti-V magnetite deposits in the Panxi region. However, except for their coeval ages, the genetic relations between the ore-bearing intrusions and extrusive rocks are poorly understood. Phase equilibria analysis (Q-PI-OI-Opx-Cpx system) has been carried out to elucidate whether ore-bearing Panzhihua, Xinjie and Limahe intrusions are co-magmatic with the picrites and flood basalts (including high-Ti, low-Ti and alkali basalts), respectively. In this system, the parental magma can be classified as silica-undersaturated olivine basalt and silica-saturated tholeiite. The equivalents of the parental magma of the Xinjie and Limahe peridotites and picrites and iow-Ti basalts are silica-undersaturated, whereas the Limahe gabbro-diorites and high-Ti basalts are silica-saturated. In contrast, the Panzhihua intrusion appears to be alkali character. Phase equilibria relations clearly show that the magmas that formed the Panzhihua intrusion and high-Ti basalts cannot be co-magmatic as there is no way to derive one liquid from another by fractional crystallization. On the other hand, the Panzhihua intrusion appears to be related to Permian alkali intrusions in the region, but does not appear to be related to the alkali basalts recognized in the Longzhoushan lava stratigraphy. Comparably, the Limabe intrusion appears to be a genetic relation to the picrites, whereas the Xinjie intrusion may be genetically related to be low-Ti basaits. Additionally, the gabbro-diorites and peridotites of the Limahe intrusion are not co-magmatic, and the former appears to be derived liquid from high-Ti basalts.

  15. Kellad orelis

    Index Scriptorium Estoniae

    2000-01-01

    18. VI Tallinna toomkirikus organist Ines Maidre (kaastegev Kristjan Mäeots) kontsert "Kellad orelis". Kontserdiga esitleb I. Maidre ka oma samanimelist CD-d (kujundaja Margus Haavamägi), mis on osaliselt sisse mängitud Tallinna toomkiriku Ladegasti-Saueri orelil. Tänavu tähistatakse toomkiriku Maarja kella ja Lunastaja kella 315. aastapäeva.

  16. Up-dated ore composition data (Central ore-field, Kuznetsk Alatau

    Directory of Open Access Journals (Sweden)

    Bushmanov A.

    2016-01-01

    Full Text Available Applying scanning electron microscope (SEM, energy-dispersive microanalyzer and X-ray ray fluorescence microscope the ore mineral composition in Central gold-ore field ore field (Kuznetsk Alatau was investigated. Eleven new minerals were detected in this ore field. The differentiated behavior of mineral formation stages in veinsand near-veined beresites was determined. The composition of native gold was studied, as well as the distribution of trace elements in pyrite.

  17. Hydrothermal zebra dolomite in the Great Basin, Nevada--attributes and relation to Paleozoic stratigraphy, tectonics, and ore deposits

    Science.gov (United States)

    Diehl, S.F.; Hofstra, A.H.; Koenig, A.E.; Emsbo, P.; Christiansen, W.; Johnson, Chad

    2010-01-01

    In other parts of the world, previous workers have shown that sparry dolomite in carbonate rocks may be produced by the generation and movement of hot basinal brines in response to arid paleoclimates and tectonism, and that some of these brines served as the transport medium for metals fixed in Mississippi Valley-type (MVT) and sedimentary exhalative (Sedex) deposits of Zn, Pb, Ag, Au, or barite. Numerous occurrences of hydrothermal zebra dolomite (HZD), comprised of alternating layers of dark replacement and light void-filling sparry or saddle dolomite, are present in Paleozoic platform and slope carbonate rocks on the eastern side of the Great Basin physiographic province. Locally, it is associated with mineral deposits of barite, Ag-Pb-Zn, and Au. In this paper the spatial distribution of HZD occurrences, their stratigraphic position, morphological characteristics, textures and zoning, and chemical and stable isotopic compositions were determined to improve understanding of their age, origin, and relation to dolostone, ore deposits, and the tectonic evolution of the Great Basin. In northern and central Nevada, HZD is coeval and cogenetic with Late Devonian and Early Mississippian Sedex Au, Zn, and barite deposits and may be related to Late Ordovician Sedex barite deposits. In southern Nevada and southwest California, it is cogenetic with small MVT Ag-Pb-Zn deposits in rocks as young as Early Mississippian. Over Paleozoic time, the Great Basin was at equatorial paleolatitudes with episodes of arid paleoclimates. Several occurrences of HZD are crosscut by Mesozoic or Cenozoic intrusions, and some host younger pluton-related polymetallic replacement and Carlin-type gold deposits. The distribution of HZD in space (carbonate platform, margin, and slope) and stratigraphy (Late Neoproterozoic Ediacaran-Mississippian) roughly parallels that of dolostone and both are prevalent in Devonian strata. Stratabound HZD is best developed in Ediacaran and Cambrian units, whereas

  18. Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

    Science.gov (United States)

    Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

    2015-04-01

    with kaolinite and gibbsite, which make it low grade. Massive iron ores are devoid of any lamination and usually associated with BHJ and lower shale. The thickness of the massive ore layer varies with the location. The massive iron ore grades in to well-developed bedded BHJ in depth. Blue dust occurs in association with BHJ as pockets and layers. Although blue dust and friable ore are both powdery ores, and subjected to variable degree of deformation, leading to the formation of folding, faulting and joints of complex nature produce favourable channels. Percolating water play an important role in the formation of blue dust and the subterranean solution offers the necessary acidic environment for leaching of quartz from the BHJ. The dissolution of silica and other alkalis are responsible for the formation of blue dust. The friable and powdery ore on the other hand are formed by soft laminated ore. As it is formed from the soft laminated ore, its alumina content remains high similar to soft laminated ore compaired to blue dust. Mineralogy study suggests that magnetite was the principal iron oxide mineral, now a relict phase whose depositional history is preserved in BHJ, where it remains in the form of martite. The platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Hard laminated ores, martite-goethite ore and soft laminated ore are resultant of desilicification process through the action of hydrothermal fluids. Geochemistry of banded iron-formations of the Noamundi-Koira iron ore deposits shows that they are detritus-free chemical precipitates. The mineralogical and geochemical data suggest that the hard laminated, massive, soft laminated ores and blue dust had a genetic lineage from BIF's aided with certain input from hydrothermal activity. The comparative study of major elemental composition of the basin samples and while plotting a binary diagram, it shows a relation between major oxides against

  19. Helium isotope data from the Goldfield epithermal system, Nevada: Evidence for volatile input from a primitive mantle source during ore formation

    Science.gov (United States)

    Hofstra, A. H.; Manning, A. H.

    2013-12-01

    Goldfield is the largest high sulfidation epithermal gold mining district in the United States with over 130 t of gold production and 23 sq. km. of argillic alteration (with alunite, pyrophyllite, or kaolinite). It formed at 20.0×0.5 Ma in an andesite to rhyolite volcanic field in the ancestral Cascades continental magmatic arc. Previous stable isotope studies of quartz, alunite, and sulfide minerals suggest that the gold ores formed in a magmatic vapor plume derived from a subjacent porphyry intrusion, which displaced and mixed with meteoric groundwater at shallow levels. The isotopic compositions of He, Ne, and Ar trapped in fluid inclusions in hydrothermal minerals (Cu-sulfides and sulfosalts, pyrite, quartz) were measured to further constrain volatile source and migration processes. Gases were released by thermal decrepitation at 300°C and analyzed using a high resolution static sector mass spectrometer. The isotopic compositions of Ne and Ar are typical of air-saturated water (ASW), indicating that the samples contain little nucleogenic Ne or radiogenic Ar derived from underlying old crustal sources. In contrast, He/Ne and He/Ar ratios are much greater than ASW, indicating that a component of He was produced in the subsurface. The wide range of He R/Ra values, 0.4 to 20, suggests that He was derived from both crustal and mantle sources. 4He/40Ar* and 4He/21Ne* systematics are characteristic of magma degassing. The highest R/Ra values (15-20) are well above those previously reported for modern volcanic rocks and geothermal fluids in subduction-related arcs. Such R/Ra values indicate a primitive mantle source, perhaps below the subducting slab. We hypothesize that the discharge of metal-laden fluids from the subjacent porphyry intrusion was influenced by the input of hot volatiles from mafic mantle-derived magmas. This scenario implies a magma column that remained open to the flux of volatiles over a considerable depth range, from the mantle to the shallow

  20. Metasomatism and ore formation at contacts of dolerite with saliferous rocks in the sedimentary cover of the southern Siberian platform

    Science.gov (United States)

    Mazurov, M. P.; Grishina, S. N.; Istomin, V. E.; Titov, A. T.

    2007-08-01

    The data on the mineral composition and crystallization conditions of magnesian skarn and magnetite ore at contacts of dolerite with rock salt and dolomite in ore-bearing volcanic—tectonic structures of the Angara—Ilim type have been integrated and systematized. Optical microscopy, scanning and transmission electron microscopy, electron microprobe analysis, electron paramagnetic resonance, Raman and IR spectroscopy, and methods of mineralogical thermometry were used for studying minerals and inclusions contained therein. The most diverse products of metasomatic reactions are found in the vicinity of a shallow-seated magma chamber that was formed in Lower Cambrian carbonate and saliferous rocks under a screen of terrigenous sequences. Conformable lodes of spinel-forsterite skarn and calciphyre impregnated with magnesian magnetite replaced dolomite near the central magma conduit and apical portions of igneous bodies. At the postmagmatic stage, the following mineral assemblages were formed at contacts of dolerite with dolomite: (1) spinel + fassaite + forsterite + magnetite (T = 820-740°C), (2) phlogopite + titanite + pargasite + magnetite (T = 600 500°C), And (3) clinochlore + serpentine + pyrrhotite (T = 450°C and lower). Rock salt is transformed at the contact into halitite as an analogue of calciphyre. The specific features of sedimentary, contact-metasomatic, and hydrothermal generations of halite have been established. The primary sedimentary halite contains solid inclusions of sylvite, carnallite, anhydrite, polyhalite, quartz, astrakhanite, and antarcticite; nitrogen, methane, and complex hydrocarbons have been detected in gas inclusions; and the liquid inclusions are largely aqueous, with local hydrocarbon films. The contact-metasomatic halite is distinguished by a fine-grained structure and the occurrence of anhydrous salt phases (CaCl2 · KCl, CaCl2, nMgCl2 · mCaCl2) and high-density gases (CO2, H2S, N2, CH4, etc.) as inclusions. The low

  1. The study of molybdenite types related to the ore processing plant of the Sar Cheshmeh mine

    Directory of Open Access Journals (Sweden)

    Balandeh Aminzadeh

    2010-11-01

    Full Text Available Molybdenite occurs in five forms in the Sar Cheshmeh porphyry copper deposit, namely, (1-veinlets with quartz-molybdenite, (2-veinlets with quartz-molydenite that were filled with pyrite, (3-veinlets with quartz-molybdenite-pyrite–chalcopyrite, (4-Molybdenite veinlets with very low quartz and (5-disseminated molybdenite grains. Because of their large size, the veinlet-related molybdenite grains are easily liberated from the gangue minerals, provided the grinding is properly conducted (74 micron. Because of their fine-grain size, the disseminated molybdenite grains are not liberated from the gangue and enter the tailings during the flotation process.

  2. Processing of lateritic ores

    Energy Technology Data Exchange (ETDEWEB)

    Collier, D.E.; Ring, R.J. [Environment Division, Australian Nuclear Science and Technology Organisation, Menai, New South Wales (Australia); McGill, J.; Russell, H. [Energy Resources of Australia Ltd., Ranger Mine, Jabiru, Northern Territory (Australia)

    2000-07-01

    Highly weathered or lateritic ores that contain high proportions of fine clay minerals present specific problems when they are processed to extract uranium. Of perhaps the greatest significance is the potential of the fine minerals to adsorb dissolved uranium (preg-robbing) from leach liquors produced by processing laterites or blends of laterite and primary ores. These losses can amount to 25% of the readily soluble uranium. The clay components can also restrict practical slurry densities to relatively low values in order to avoid rheology problems in pumping and agitation. The fine fractions also contribute to relatively poor solid-liquid separation characteristics in settling and/or filtration. Studies at ANSTO have characterised the minerals believed to be responsible for these problems and quantified the effects of the fines in these types of ores. Processing strategies were also examined, including roasting, resin-in-leach and separate leaching of the laterite fines to overcome potential problems. The incorporation of the preferred treatment option into an existing mill circuit is discussed. (author)

  3. Evaluation of physical health and its relation with history of work accidents in workers of the Central Iron Ore Company of Iran

    Directory of Open Access Journals (Sweden)

    Gholam Hossein Halvani

    2013-01-01

    Full Text Available Aims: This study was conducted to determine the state of physical symptoms of the Iranian Central Iron Ore Company workers and its relation with history of work accidents. Materials and Methods: This cross-sectional descriptive study was performed at the Iranian Central Iron Ore Company and included 388 workers sampled randomly out of 2100 workers. Research tool was a two-part questionnaire that its reliability was determined by some of researchers. Data was analyzed by SPSS (Statistical Package for Social Science software and statistical tests included variance analysis and Pearson′ correlation tests. Results: According to the findings, 80.9% had favorable physical health conditions and there was a significant relationship between physical health condition, history of work accidents, cigarette smoking and type of work. Conclusion: Considering the strong relationship between physical health and history of work accidents, it is proposed that high-level managers of the Central Iron Ore Company of Iran should pay special attention to the improvement of physical health, psychological, social, and welfare levels.

  4. Mineralogical-Geochemical Peculiarities of Ores in Pyritaceous Fields of Filizchai Type in the Greater Caucasus

    Directory of Open Access Journals (Sweden)

    NOVRUZ A. NOVRUZOV

    2010-12-01

    Full Text Available Pyritaceous fields of the south slope of the Greater Caucasus confined to the Lower-Middle Jurassic sandy clayey deposits are: polygenic polychrone formations which were formed by a complex of hydrothermal sedimentary, hydrothermal metasomatic and hydrothermal metamorphogenic processes of ore formation. Filizchai pyritaceous polymetallic field is the largest in the region and can be characterized by diversity of texture-mineralogical types of ores, rich mineral composition and with geochemical spectrum. Some of the admixture components (Cd, In, Tl, Ga, Ge, Se, Hg are only in isomorphic forms in ores, others (Te, Bi, Au, Ag, Co, Sn, As along with it characterize in their own minerals. The Co is mainly concentrated in pyrite, pyrrhotine; Ag, Bi and also Te – in galenite and chalcopyrite; Se – in pyrite, pyrrhotine and galenite; in sphalerite (mainly in marmatite and chalcopyrite; Cd, Ga, Ge – in sphalerite, mainly in cleiophane; Au – in pyrite and chalcopyrite; Tl – in galenite and colloform pyrite. In all sulphides selenium prevails over tellurium (excepting the late chalcopyrite and cobalt over nickel. Maximum amount of cobalt is confined to pyrite from pyritaceous polymetallic ores and late generation of pyrrhotine. The nature of the connection between chemical elements in ores coordinates with determined stages of minerals formation. The main productive stage of ore formation bringing the main mass of gold, silver, rare and other precious components of ores are sulphosalt polymetallic stage of sulphur ploymetallic stage. Comparative analysis of absolute content of gold, silver and values of gold-silver relation in pyrite fields ores of region with appropriate values in meteorite standard indirectly indicates the relationship between gold-silver mineralization and assimilation crust source.

  5. Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran) using REE geochemistry

    Science.gov (United States)

    Mokhtari, Mir Ali Asghar; Zadeh, Ghader Hossein; Emami, Mohamad Hashem

    2013-06-01

    Rare earth elements in apatites of different ore types show characteristic patterns which are related to different modes of formation of the ores. Most of the apatite-bearing iron ores are associated with alkaline magmas with LREE/HREE fractionation varying from moderate to steep. Iron-apatite deposits in Posht-e-Badam Block (Central Iran) have a high concentration of REE (more than 1000 ppm up to 2.5%), and show a strong LREE/HREE ratio with a pronounced negative Eu anomaly. This REE pattern is typical of magmatic apatite and quiet distinct from sedimentary apatites (phosphorites) which have a low REE contents and Ce negative anomalies. On the other hand, they are comparable to the REE patterns of apatites in Kiruna-type iron ores in different parts of the world. The REE patterns of apatites, iron-apatite ores and iron ores are similar and only have different REE contents. This similarity indicates a genetic relation for these rocks. Most of the iron-apatite deposits in Central Iran have similar REE patterns too, which in turn show a genetic relation for all of these deposits. This similarity indicates a similar origin and processes in their genesis. There are some small intrusions around some of the iron-apatite deposits that are petrographically identified as syenite and gabbro. These intrusions also have REE patterns similar to that of iron-apatite ores. This demonstrates a genetic relation between these intrusions and iron-apatite ores. The REE patterns of apatites in different deposits of Posht-e-Badam Block iron-apatite ores show an affinity to alkaline to sub-alkaline magmas and rifting environment. The alkaline host rocks of Central Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE-NNW fault lines). A probable source for this large scale ore forming processes is relatively low partial melting of mantle rocks. The ores have originated by magmatic differentiation as a late phase in the volcanic cycle

  6. Genesis of iron-apatite ores in Posht-e-Badam Block (central Iran) using REE geochemistry

    Indian Academy of Sciences (India)

    Mir Ali Asghar Mokhtari; Ghader Hossein Zadeh; Mohamad Hashem Emami

    2013-06-01

    Rare earth elements in apatites of different ore types show characteristic patterns which are related to different modes of formation of the ores. Most of the apatite-bearing iron ores are associated with alkaline magmas with LREE/HREE fractionation varying from moderate to steep. Iron-apatite deposits in Posht-e-Badam Block (Central Iran) have a high concentration of REE (more than 1000 ppm up to 2.5%), and show a strong LREE/HREE ratio with a pronounced negative Eu anomaly. This REE pattern is typical of magmatic apatite and quiet distinct from sedimentary apatites (phosphorites) which have a low REE contents and Ce negative anomalies. On the other hand, they are comparable to the REE patterns of apatites in Kiruna-type iron ores in different parts of the world. The REE patterns of apatites, iron-apatite ores and iron ores are similar and only have different REE contents. This similarity indicates a genetic relation for these rocks. Most of the iron-apatite deposits in Central Iran have similar REE patterns too, which in turn show a genetic relation for all of these deposits. This similarity indicates a similar origin and processes in their genesis. There are some small intrusions around some of the iron-apatite deposits that are petrographically identified as syenite and gabbro. These intrusions also have REE patterns similar to that of iron-apatite ores. This demonstrates a genetic relation between these intrusions and iron-apatite ores. The REE patterns of apatites in different deposits of Posht-e-Badam Block iron-apatite ores show an affinity to alkaline to sub-alkaline magmas and rifting environment. The alkaline host rocks of Central Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE–NNW fault lines). A probable source for this large scale ore forming processes is relatively low partial melting of mantle rocks. The ores have originated by magmatic differentiation as a late phase in the volcanic cycle

  7. GEOLOGICAL AND GEOCHEMICAL CHARACTERISTICS AND RELATED MINERALIZATION OF CHERT FORMATIONS IN SOUTH TIBET

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    There occur abundant cherts in the Mesozoic and Cenozoic strata in southern Tibet. Some of them possess characteristic hydrothermal structures such as layered, laminated, massive and breccia structures.Ratios of Al/(Al+Fe+Mn), Co/Ni, Fe/Ti and TiO2-Al2O3 demonstrate that their origin is related to hydrothermal sedimentation. The chert formations have close relationship with Sb, Au and poly-metallic mineralization, and the ore-forming fluid show strong correlation with fossil hydrothermal water.

  8. The North American iron ore industry: a decade into the 21st century

    Science.gov (United States)

    Jorgenson, John D.; Perez, A. A

    2011-01-01

    During the 20th century, the iron ore mining industries of Canada and the United States passed through periods of transformation. The beginning of the 21st century has seen another period of transformation, with the failure of a number of steel companies and with consolidation of control within the North American iron ore industry. Canadian and United States iron ore production and the market control structure involved are changing rapidly. Consolidation of ownership, formation of foreign joint ventures, divestitures of upstream activities by steelmakers, and industry changes to ensure availability of feedstocks all played a role in recent developments in the North American iron ore industry. Canadian and U.S. iron ore operations and their strong linkage to downstream production, although isolated, must also be considered within the context of the changing global economy. Projects using new technology to produce direct reduced iron nuggets of 96-98% iron content and other projects designed to produce steel at minesites may once again change the face of the iron ore industry. Social and environmental issues related to sustainable development have had a significant effect on the North American iron ore industry.

  9. Tectonic ore-controlling in the middle southern segment of Da Hinggan Ling, Northeast China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Studies on geotectonic evolution, regionally geological characteristics and ore-forming and ore-controlling structures have shown that since the Mesozoic the Da Hinggan Ling region has entered the typical intercontinental orogenic stage, which appears to be closely related to mantle plume activities. Da Hinggan Ling is a typical mantle branch structure and possesses obvious magmatic-metamorphic complexes in the core, detachment slip beds in the periphery and overlapped fault depression basins. Moreover, all these are the principal factors leading to ore formation and ore controlling in the region. This paper also further explores the mechanism of mineralization in the middle-southern segment of Da Hinggan Ling,summaries the rules of mineralization, puts forward the models of mineralization and points out the oresearch orientations in the future time.

  10. Test of oxidation behavior of sulfide ores at ambient temperature for fire control

    Institute of Scientific and Technical Information of China (English)

    WU Chao; LI Zi-jun; LI Ming; WU Guo-min

    2007-01-01

    The coincidence of relevant factors, e.g. oxygen absorption quantity, weight increment, water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process, was tested through experiment. Based on a large number of tests for a group sample of sulfide ores from a mine, some important conclusions were obtained. The results obtained by the investigation indicate that there is no general interpretation relative to the oxygen absorption and the formation products of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature. However, the weight increment of the sulfide ore samples in the oxidation process at ambient temperature has a linear relationship with the quantity of oxygen absorption.

  11. The Krásná Hora, Milešov, and Příčovy Sb-Au ore deposits, Bohemian Massif: mineralogy, fluid inclusions, and stable isotope constraints on the deposit formation

    Science.gov (United States)

    Němec, Matěj; Zachariáš, Jiří

    2017-04-01

    The Krásná Hora-Milešov and Příčovy districts (Czech Republic) are the unique examples of Sb-Au subtype orogenic gold deposits in the Bohemian Massif. They are represented by quartz-stibnite veins and massive stibnite lenses grading into low-grade, disseminated ores in altered host rocks. Gold postdates the stibnite and is often replaced by aurostibite. The ore zones are hosted by hydrothermally altered dikes of lamprophyres (Krásná Hora-Milešov) or are associated with local strike-slip faults (Příčovy). Formation of Sb-Au deposits probably occurred shortly after the main gold-bearing event (348-338 Ma; Au-only deposits) in the central part of the Bohemian Massif. Fluid inclusion analyses suggest that stibnite precipitated at 250 to 130 °C and gold at 200 to 130 °C from low-salinity aqueous fluids. The main quartz gangue hosting the ore precipitated from the same type of fluid at about 300 °C. Early quartz-arsenopyrite veins are not associated with the Sb-Au deposition and formed from low-salinity, aqueous-carbonic fluid at higher pressure and temperature ( 250 MPa, 400 °C). The estimated oxygen isotope composition of the ore-bearing fluid (4 ± 1‰ SMOW; based on post-ore calcite) suggests its metamorphic or mixed magmatic-metamorphic origin and excludes the involvement of meteoric water. Rapid cooling of warm hydrothermal fluids reacting with "cold" host rock was probably the most important factor in the formation of both stibnite and gold.

  12. Challenges facing the North American iron ore industry

    Science.gov (United States)

    Jorgenson, J.D.

    2005-01-01

    During the 20th century, the iron ore mining industries of Canada and the United States passed through several periods of transformation. The beginning of the 21st century has seen yet another period of transformation, with the economic failure of a number of steel companies, the acquisition of their facilities by more viable steelmakers, and the consolidation of control within the North American iron ore industry. Changes in Canadian and United States iron ore production and the market control structure involved are analysed. The consolidation of ownership, formation of foreign joint ventures within Nordi America, planned divestitures of upstream activities by steelmakers, and industry changes made to ensure availability of feedstocks will be reviewed. The ttaditional isolation of the Canadian and United States iron ore operations and their strong linkage to downstream steel production will be discussed in the context of a changing global economy. Management-labour conflicts that have taken place and agreements made during 2000 through 2004 will be discussed in the context of the economic environment leading up to these agreements. Cooperative agreements between competing Canadian and United States companies to resolve client needs in processing and blending will be examined. A joint industry-government project designed to use new technology to produce direct reduced iron nuggets of 96 - 98 per cent iron content using non-coking coals will also be assessed. Changes in iron ore transportation methods, ownership and infrastructure will be reviewed for both rail and inland waterway transport between Canadian and United States companies. A brief analysis of social and environmental issues relating to sustainable development of the Canadian-United States iron ore industry will be included.

  13. Advances in research of sulphide ore textures and their implications for ore genesis

    Institute of Scientific and Technical Information of China (English)

    GU Lianxing; ZHENG Yuanchuan; TANG Xiaoqian; WU Changzhi; HU Wenxuan

    2006-01-01

    Important advances in research of sulphide ore textures in recent years have deepened our understanding of ore genesis of related mineral deposits. Pressure solution of sulphide minerals has been suggested as a mechanism for remobilization of ore materials,whereas pressure solution of the gangues is believed to raise the grade of the primary ores. We have known that precipitation of base metal sulphides from fluids prefers crystal and crack surfaces of pyrite to form overgrowth. Therefore, pyrite-bearing embryo beds in a sedimentary sequence can be acted as effective crystal seed beds and are favorable for fluid overprinting to form huge statabound deposits. Texture studies of various sulphides can be used to interpret the entire history of sedimentation, diagenesis, deformation and metamorphism of the ores. The study of chalcopyrite disease in sphalerite has brought about the idea of zone refining, and given a new explanation to metal zonation in massive sulphide deposits. Ductile shearing of sulphide ores may form ore mylonites, which will become oreshoots enriched in Cu, Au and Ag during late-stage fluid overprinting. Despite that various modern analytical techniques are being rapidly developed, ore microscopy remains to be an unreplaceable tool for ore geologists. Combined with these modern techniques, this tool will help accelerate the development of theories on ore genesis.

  14. Petrogenesis of Paleocene-Eocene porphyry deposit-related granitic rocks in the Yaguila-Sharang ore district, central Lhasa terrane, Tibet

    Science.gov (United States)

    Zhao, Junxing; Li, Guangming; Evans, Noreen J.; Qin, Kezhang; Li, Jinxiang; Zhang, Xia'nan

    2016-11-01

    The Paleocene-Eocene ore deposits in the Gangdese Metallogenic Belt, Tibet, are thought to have been formed during the main period of India-Asia continental collision. This paper reports the whole-rock major element, trace element, and Sr-Nd-Hf isotopic compositions and zircon trace element contents of volcanic and intrusive rocks from the Paleocene Yaguila skarn Pb-Zn-Ag deposit and adjacent Eocene Sharang porphyry Mo deposit in the central Lhasa terrane, Tibet. Geochemical signatures and Nd-Hf isotopic compositions indicate that the Yaguila Cretaceous rhyolitic rocks were formed by the melting of ancient continental crust, whereas the Paleocene causative granite porphyry may have resulted from the interaction between mantle-derived and crustal-derived materials when continental collision was initiated. The dramatic increase of εNd(t) values between emplacement of the granite porphyry and later porphyritic biotite granite suggests a greater involvement of mantle materials during the crystallization of the barren biotite granite stock. The post-ore Miocene granodiorite porphyry has a similar geochemical signature to the Sharang Miocene dykes, suggesting they were both generated from melting of enriched lithospheric mantle. Nd-Hf mixing calculations indicate an increasing contribution of mantle materials in Paleocene to Eocene intrusions, consistent with the regional tectonic model of Neo-Tethyan oceanic slab roll-back and break-off. Zircons from both the Yaguila and Sharang ore-related porphyries have higher Ce anomalies than those from the barren granitoids, suggesting that Mo mineralization was closely related to highly oxidized and differentiated magma. The fertile intrusions in the Yaguila-Sharang district contain EuN/EuN∗ values from 0.3 to 0.6, higher than the non-mineralized intrusions. The processes of early crystallization of plagioclase and/or SO2-degassing from underlying magma can explain the observed negative Eu anomalies in zircon.

  15. Endogenic Au-Ag polymetallic ore deposits and ore-bearing potentiality of strata

    Institute of Scientific and Technical Information of China (English)

    WANG Baode; NIU Shuyin; SUN Aiqun; XIE Yan; LUO Yi; LIU Hailong; WANG Yanhua

    2010-01-01

    The problem of ore-bearing potentiality of the strata involves metallogenic theory and ore-search orientation. Studies of the spatial distribution of endogenic Au-Ag polymetallic ore deposits in North Hebei indicated that the strata in which ore deposits occurred range in age from Paleozoic, Proterozoic to Mesozoic. In addition the ore deposits are characterized as being strata-bound in nature. The arise and establishment of "extracting" viewpoint may be attributed to the following three reasons: 1) influence by the idea of "ore-source bed"; 2) limitation of analytical techniques in the 1980s' (especially gold element); and 3) a small number of samples (sampling locations were mostly disturbed by mineralization). Studies have shown that ore-forming materials would most probably come from the deep interior of the Earth. Deep-seated ore-bearing materials including Au-Ag polymetals were brought to the shallow levels by way of mantle plume-mantle sub-plume-mantle branch structure multi-stage evolution, finally leading to the formation of ore deposits.

  16. Diet-related DNA adduct formation in relation to carcinogenesis.

    Science.gov (United States)

    Hemeryck, Lieselot Y; Vanhaecke, Lynn

    2016-08-01

    The human diet contributes significantly to the initiation and promotion of carcinogenesis. It has become clear that the human diet contains several groups of natural foodborne chemicals that are at least in part responsible for the genotoxic, mutagenic, and carcinogenic potential of certain foodstuffs. Electrophilic chemicals are prone to attack nucleophilic sites in DNA, resulting in the formation of altered nucleobases, also known as DNA adducts. Since DNA adduct formation is believed to signal the onset of chemically induced carcinogenesis, the DNA adduct-inducing potential of certain foodstuffs has been investigated to gain more insight into diet-related pathways of carcinogenesis. Many studies have investigated diet-related DNA adduct formation. This review summarizes work on known or suspected dietary carcinogens and the role of DNA adduct formation in hypothesized carcinogenesis pathways.

  17. Oolitic ores in the Bakchar iron-ore cluster (Tomsk Oblast)

    Science.gov (United States)

    Rudmin, M. A.; Mazurov, A. K.

    2016-12-01

    Oolitic iron ores are typified, and their morphology and composition are studied. Special attention is focused on the character of distribution of valuable and harmful admixtures and determination of the principal minerals concentrating these elements. As a result of this study, three types of ores are identified, such as "loose" ores, cemented ores with glauconite-chlorite-clay cement, and well-cemented ores with siderite cement. The morphology and composition of the ore oolites are characterized. The forms of occurrence of calcium phosphates (anapaite) and phosphates of rare-earth elements (monazite, cularite) that are related to the harmful phosphorus admixture are described. According to the analysis of the elemental composition, the fractions of (-1…+0.2) and (-1…+0.1) mm in the western and eastern segments, respectively, may be promising for processing.

  18. Fluid dynamics, particulate segregation, chemical processes, and natural ore analog discussions that relate to the potential for criticality in Hanford tanks

    Energy Technology Data Exchange (ETDEWEB)

    Barney, G.S.

    1996-09-27

    This report presents an in-depth review of the potential for nuclear criticality to occur in Hanford defense waste tanks during past, current and future safe storage and maintenance operations. The report also briefly discusses the potential impacts of proposed retrieval activities, although retrieval was not a main focus of scope. After thorough review of fluid dynamic aspects that focus on particle segregation, chemical aspects that focus on solubility and adsorption processes that might concentrate plutonium and/or separate plutonium from the neutron absorbers in the tank waste, and ore-body formation and mining operations, the interdisciplinary team has come to the conclusion that there is negligible risk of nuclear critically under existing storage conditions in Hanford site underground waste storage tanks. Further, for the accident scenarios considered an accidental criticality is incredible.

  19. Geological characteristics and genesis of iron ores of Zhaoanzhuang Formation in Wuyang iron ore field of Henan%河南省舞阳铁矿田赵案庄组铁矿地质特征及成因分析

    Institute of Scientific and Technical Information of China (English)

    刘立新; 李怀乾; 贾兴杰; 王伟中; 王夏

    2014-01-01

    赵案庄矿区是舞阳矿田三大矿区之一,20世纪50~70年代该矿区在500m 以浅共提交资源储量1.3亿吨。通过近期的普查工作探获资源储量5000t。笔者根据以往的地质资料、结合本次的普查结果,对矿体基本地质特征进行了总结、对成因特点进行了分析、为下步的详查工作提供参考。%Zhaoanzhuang iron mining area is one of the three primary mining areas of Wuyang iron ore field. From 1950s to 1970s this mining area has proven reserves of 130 million tons above depth of 500m.A recent reconnaissance survey has verified reserves of 5000 tons.Based on historical geological data and findings of the recent reconnaissance survey,the author analyzes basic geological characteristics of ore-bodies and its genesis and provides references for the following detailed survey works.

  20. Magmatic-vapor expansion and the formation of high-sulfidation gold deposits: Structural controls on hydrothermal alteration and ore mineralization

    Science.gov (United States)

    Berger, B.R.; Henley, R.W.

    2011-01-01

    High-sulfidation copper-gold lode deposits such as Chinkuashih, Taiwan, Lepanto, Philippines, and Goldfield, Nevada, formed within 1500. m of the paleosurface in volcanic terranes. All underwent an early stage of extensive advanced argillic silica-alunite alteration followed by an abrupt change to spatially much more restricted stages of fracture-controlled sulfide-sulfosalt mineral assemblages and gold-silver mineralization. The alteration as well as ore mineralization stages of these deposits were controlled by the dynamics and history of syn-hydrothermal faulting. At the Sulfate Stage, aggressive advanced argillic alteration and silicification were consequent on the in situ formation of acidic condensate from magmatic vapor as it expanded through secondary fracture networks alongside active faults. The reduction of permeability at this stage due to alteration decreased fluid flow to the surface, and progressively developed a barrier between magmatic-vapor expansion constrained by the active faults and peripheral hydrothermal activity dominated by hot-water flow. In conjunction with the increased rock strength resulting from alteration, subsequent fault-slip inversion in response to an increase in compressional stress generated new, highly permeable fractures localized by the embrittled, altered rock. The new fractures focused magmatic-vapor expansion with much lower heat loss so that condensation occurred. Sulfide Stage sulfosalt, sulfide, and gold-silver deposition then resulted from destabilization of vapor phase metal species due to vapor decompression through the new fracture array. The switch from sulfate to sulfide assemblages is, therefore, a logical consequence of changes in structural permeability due to the coupling of alteration and fracture dynamics rather than to changes in the chemistry of the fluid phase at its magmatic source. ?? 2010.

  1. Experimental study on preferential solution flow during dump leaching of low-grade ores

    Institute of Scientific and Technical Information of China (English)

    YIN Sheng-hua; WU Ai-xiang; SU Yong-ding; ZHANG Jie

    2007-01-01

    The phenomenon of preferential solution flow during dump leaching of low-grade ores was studied. The formative mechanism of preferential solution flow was investigated through analyzing the relationship between permeability and ore diameter,and the relationship between surface tension and ore diameter. The preferential solution flow happened within the fine ore area when the dump was unsaturated. And it could happen within the coarse ore area when the dump became saturated. The results of experiment show that the outflow of coarse ore area increases sharply with higher applied rate. The outflow of fine ore area is greater than that of coarse ore area when the applied rate is below 3.2 L/min, and the preferential solution flow happens in fine ore area. But the preferential solution flow happens in coarse ore area when the applied rate is higher than 3.2 L/min. The result of the experiment is consistent with the mechanism analyzing.

  2. Mortality from myocardial infarction in relation to exposure to vibration and dust among a cohort of iron-ore miners in Sweden.

    Science.gov (United States)

    Björ, Bodil; Burström, Lage; Eriksson, Kåre; Jonsson, Håkan; Nathanaelsson, Lena; Nilsson, Tohr

    2010-03-01

    The aim of this study was to investigate myocardial infarction (MI) mortality in relation to exposure to hand/arm vibration (HAV) and whole body vibration (WBV) as well as exposure to dust among men employed in two Swedish iron-ore mines. This study comprised employed men at two iron-ore mines in Sweden who had been employed for at least 1 year from 1923 up to 1996. The causes of death were obtained from the national cause of death register from 1952 to 2001. Myocardial infarction mortality was obtained by linking personal identification numbers to the national cause of death register. Poisson regression was used for risk estimations on exposure-response relation, and analyses were made on the two age groups 60 years. Relative risks for MI mortality in relation to exposure were significantly increased for exposure (0/>0) to WBV (RR 1.18, 95% CI 1.06 to 1.31) and dust (RR 1.15, 95% CI 1.02 to 1.31), and the results indicated an exposure-response relation for WBV and dust separately. For 60 years and younger, exposure to HAV (0/>0) (RR 1.34, 95% CI 1.03 to 1.74) and WBV (0/>0) (RR 1.39, 95% CI 1.13 to 1.72) increased the risk of MI mortality. An exposure-response was found for HAV and WBV, as the medium and high exposed categories showed significantly increased risk estimates. None of the exposures significantly increased the risk in the group above 60 years. The increased risk estimates for exposure to WBV remained when adjusting for exposure to dust. The results for the working age (< or =60 years) group showed significantly increased MI mortality for univariate exposure to HAV, WBV and dust. We found an association between increased mortality from MI and occupational exposure to WBV, and the risk remained after adjustment for dust exposure.

  3. Satellite formation flying relative dynamics, formation design, fuel optimal maneuvers and formation maintenance

    CERN Document Server

    Wang, Danwei; Poh, Eng Kee

    2017-01-01

    This book systematically describes the concepts and principles for multi-satellite relative motion, passive and near passive formation designs, trajectory planning and control for fuel optimal formation maneuvers, and formation flying maintenance control design. As such, it provides a sound foundation for researchers and engineers in this field to develop further theories and pursue their implementations. Though satellite formation flying is widely considered to be a major advance in space technology, there are few systematic treatments of the topic in the literature. Addressing that gap, the book offers a valuable resource for academics, researchers, postgraduate students and practitioners in the field of satellite science and engineering.

  4. Genesis of Gold- Silver Deposits in Qingchengzi Ore Field

    Institute of Scientific and Technical Information of China (English)

    Wei Min

    2001-01-01

    The gold - silver complex ore field of Qingchengzi is located in Liaohe group of Liaodong rift. The gold - silver ore bodies mainly lie in Dashiqiao group and Gaixian group, which provides ore - forming materials for the mineralization. For taking place multi - period and multi - stage magmatic activities, the ore - forming materials in the formation had had dynamothermal metamorphism for a long time and enriched and formed ore bodies after magmatism in Indo- Chinese and Yanshan epoch. The ore bodies are controlled by stratigraphic formation and stored in the interformational faults and schistosity belts. Silicalite is the most important indicator for searching them. Although the Pb - Zn and the gold - silver deposits are the same series of mineralized products, their positions are different, resulting from the differences of elements nature and mineralized conditions. The gold silver deposits belong to strata - bound and hysterogenetic mesothermal - epithermal deposit.

  5. Geochemistry of Rare Earth Elements in Xikeng Ag-Pb-Zn Ore Deposit, South Anhui, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, a comparative study is done on the geochemical charateristics of REE in ore, ore-hosted rocks of Lantian group, granite related to ore deposit, and altered rocks for tracing origin of ore-forming materials. The result indicates that the ore-forming fluid and ore-forming materials for Xikeng silver-polymetallic ore deposit were derived from Yixian granite's magmatic activity. Water-rock reaction of the hydrothermal fluid with the carbonate-rich stratum led the altered rock to relatively enrich in HREE.

  6. Star Formation Relations in the Milky Way

    Science.gov (United States)

    Vutisalchavakul, Nalin; Evans, Neal J., II; Heyer, Mark

    2016-11-01

    The relations between star formation and properties of molecular clouds (MCs) are studied based on a sample of star-forming regions in the Galactic Plane. Sources were selected by having radio recombination lines to provide identification of associated MCs and dense clumps. Radio continuum emission and mid-infrared emission were used to determine star formation rates (SFRs), while 13CO and submillimeter dust continuum emission were used to obtain the masses of molecular and dense gas, respectively. We test whether total molecular gas or dense gas provides the best predictor of SFR. We also test two specific theoretical models, one relying on the molecular mass divided by the free-fall time, the other using the free-fall time divided by the crossing time. Neither is supported by the data. The data are also compared to those from nearby star-forming regions and extragalactic data. The star formation “efficiency,” defined as SFR divided by mass, spreads over a large range when the mass refers to molecular gas; the standard deviation of the log of the efficiency decreases by a factor of three when the mass of relatively dense molecular gas is used rather than the mass of all of the molecular gas.

  7. Whole-body Vibration Exposure of Drill Operators in Iron Ore Mines and Role of Machine-Related, Individual, and Rock-Related Factors.

    Science.gov (United States)

    Chaudhary, Dhanjee Kumar; Bhattacherjee, Ashis; Patra, Aditya Kumar; Chau, Nearkasen

    2015-12-01

    This study aimed to assess the whole-body vibration (WBV) exposure among large blast hole drill machine operators with regard to the International Organization for Standardization (ISO) recommended threshold values and its association with machine- and rock-related factors and workers' individual characteristics. The study population included 28 drill machine operators who had worked in four opencast iron ore mines in eastern India. The study protocol comprised the following: measurements of WBV exposure [frequency weighted root mean square (RMS) acceleration (m/s(2))], machine-related data (manufacturer of machine, age of machine, seat height, thickness, and rest height) collected from mine management offices, measurements of rock hardness, uniaxial compressive strength and density, and workers' characteristics via face-to-face interviews. More than 90% of the operators were exposed to a higher level WBV than the ISO upper limit and only 3.6% between the lower and upper limits, mainly in the vertical axis. Bivariate correlations revealed that potential predictors of total WBV exposure were: machine manufacturer (r = 0.453, p = 0.015), age of drill (r = 0.533, p = 0.003), and hardness of rock (r = 0.561, p = 0.002). The stepwise multiple regression model revealed that the potential predictors are age of operator (regression coefficient β = -0.052, standard error SE = 0.023), manufacturer (β = 1.093, SE = 0.227), rock hardness (β = 0.045, SE = 0.018), uniaxial compressive strength (β = 0.027, SE = 0.009), and density (β = -1.135, SE = 0.235). Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

  8. Ores and Climate Change - Primary Shareholders

    Science.gov (United States)

    Stein, Holly J.; Hannah, Judith L.

    2015-04-01

    Many in the economic geology community concern themselves with details of ore formation at the deposit scale, whether tallying fluid inclusion data to get at changes in ore-forming fluids or defining structures that aid and abet mineralization. These compilations are generally aimed at interpretation of events at the site of ore formation, with the goal being assignment of the deposit to a sanctioned ore deposit model. While providing useful data, this approach is incomplete and does not, by itself, serve present-day requirements for true interdisciplinary science. The ore-forming environment is one of chaos and disequilibrium at nearly all scales (Stein, 2014). Chaos and complexity are documented by variably altered rocks, veins or disseminated mineralization with multi-generational fluid histories, erratic and unusual textures in host rocks, and the bitumen or other hydrocarbon products entwined within many ore deposits. This should give pause to our drive for more data as a means to find "the answer". The answer lies in the kind of data collected and more importantly, in the way we interpret those data. Rather than constructing an ever-increasing catalog of descriptive mutations on sanctioned ore deposit models (e.g., IOGC or Iron-Oxide Copper Gold deposits), the way forward is to link source and transport of metals, sulfur, and organic material with regional and ultimately whole Earth chemical evolution. Important experimental work provides chemical constraints in controlled and behaved environments. To these data, we add imagination and interpretation, always tying back to field observations. In this paper, several key points are made by way of ore deposit examples: (1) many IOCG deposits are outcomes of profound changes in the chemistry of the Earth's surface, in the interplay of the atmosphere, hydrosphere, biosphere, and lithosphere; (2) the redox history of Fe in deep earth may be ultimately expressed in the ore-forming sequence; and (3) the formation of

  9. Fluid mixing as the mechanism of formation of the Dajing Cu-Sn-Ag-Pb-Zn ore deposit, Inner Mongolia--Fluid inclusion and stable isotope evidence

    Institute of Scientific and Technical Information of China (English)

    刘伟; 李新俊; 谭骏

    2003-01-01

    Dajing Cu-Sn-Ag-Pb-Zn ore deposit, in the Inner Mongolia Autonomous Region of China, is a fissure-filling hydrothermal ore deposit. The δD values of quartz-hosted inclusion water are centered at -100‰ - -130‰. Theδ34S values of sulfide ore minerals andδ13C values of carbonate gangue minerals vary from -0.3‰ to 2.6‰ and from -2.9‰ to -7.0‰, respectively. Integrated isotopic data point to two major contributions to the mineralizing fluid that include a dominant meteoric-derived groundwater, and sulfur and carbon species from hypogene magma. Linear trends are exhibited on the gaseous H2O versus CO2 plot, and plots of CO, N2, CH4, and C2H6. It is shown by quantitative simulation that magma degassing cannot explain the linear trends. Hence, these linear trends are interpreted in terms of mixing of CO2-rich magmatic fluid with meteoric-derived groundwater. The groundwater circulated in Paleozoic sedimentary rocks and absorbed CO, N2, CH4, C2H6 and radiogenic Ar from organic matter. Cooling effects resulting from mixing have caused the precipitation of ore minerals.

  10. Remobilisation features and structural control on ore grade distribution at the Konkola stratiform Cu-Co ore deposit, Zambia

    OpenAIRE

    Torremans, K.; Gauquie, J.; Boyce, A. J.; Barrie, C.D.; Sikazwe, O.; Muchez, P.H.

    2013-01-01

    The Konkola deposit is a high grade stratiform Cu–Co ore deposit in the Central African Copperbelt in Zambia. Economic mineralisation is confined to the Ore Shale formation, part of the Neoproterozoic metasedimentary rocks of the Katanga Supergroup. Petrographic study reveals that the copper–cobalt ore minerals are disseminated within the host rock, sometimes concentrated along bedding planes, often associated with dolomitic bands or clustered in cemented lenses and in layer-parallel and irre...

  11. Geochemical Trace of Silicon Isotopes of Intrusions and Ore Veins Related to Alkali-rich Porphyry Deposits in Western Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    LIU Xianfan; YANG Zhengxi; LIU Jiaduo; WU Dechao; ZHANG Chenjiang; LI Youguo

    2004-01-01

    Western Yunnan is the well-known polymetallic province in China. It is characterized by copper-gold mineralization related to Cenozoic alkali-rich porphyry. This paper analyzes the silicon isotope data obtained from four typical alkali-rich porphyry deposits based on the dynamic fractionation principle of silicon isotope. The study shows that the ore materials should originate mainly from alkali-rich magmas, together with silicon-rich mineralizing fluids.The process of mineralization was completed by auto-metasomatism, i.e. silicon-rich mineralizing fluids (including alkali-rich porphyry and wall-rock strata) replaced and altered the country rocks and contaminated with crustal rocks during the crystallization of alkali-rich magmas. Such a process is essentially the continuance of the metasomatism of mantle fluids in crust's mineralization. This provides important evidence of silicon isotopic geochemistry for better understanding the mineralization of the Cenozoic alkali-rich porphyry polymetallic deposits

  12. In Situ Synchrotron Powder Diffraction Studies of Reduction-Oxidation (Redox) Behavior of Iron Ores and Ilmenite

    Science.gov (United States)

    Ilyushechkin, Alexander Y.; Kochanek, Mark; Tang, Liangguang; Lim, Seng

    2017-04-01

    Phase transformations of two types of iron-based oxides (iron ore and industrial-grade ilmenite) were studied using synchrotron powder diffraction of the samples processed in reducing and oxidizing atmospheres at 1173 K (900 °C) and 1223 K (950 °C), respectively. In iron ore oxidation, the disappearance of the wustite and fayalite phases was followed by hematite growth and a decrease of the magnetite phase. The magnetite phase was partially recovered by treatment in a reducing atmosphere. Ilmenite oxidation initiated decomposition of the ilmenite phase with rapid growth of hematite and gradual growth of the pseudobrookite phase. In a reducing atmosphere, ilmenite was gradually recovered from pseudobrookite with a relatively fast initial decrease in rutile and hematite content. Under reducing conditions, there was interaction of iron ore with magnesio-ferrites in iron ore-ash mixture and interaction of ilmenite with silica by the formation of fayalite.

  13. In Situ Synchrotron Powder Diffraction Studies of Reduction-Oxidation (Redox) Behavior of Iron Ores and Ilmenite

    Science.gov (United States)

    Ilyushechkin, Alexander Y.; Kochanek, Mark; Tang, Liangguang; Lim, Seng

    2017-01-01

    Phase transformations of two types of iron-based oxides (iron ore and industrial-grade ilmenite) were studied using synchrotron powder diffraction of the samples processed in reducing and oxidizing atmospheres at 1173 K (900 °C) and 1223 K (950 °C), respectively. In iron ore oxidation, the disappearance of the wustite and fayalite phases was followed by hematite growth and a decrease of the magnetite phase. The magnetite phase was partially recovered by treatment in a reducing atmosphere. Ilmenite oxidation initiated decomposition of the ilmenite phase with rapid growth of hematite and gradual growth of the pseudobrookite phase. In a reducing atmosphere, ilmenite was gradually recovered from pseudobrookite with a relatively fast initial decrease in rutile and hematite content. Under reducing conditions, there was interaction of iron ore with magnesio-ferrites in iron ore-ash mixture and interaction of ilmenite with silica by the formation of fayalite.

  14. Experimental study of ore gabbro liquid immiscibility

    Institute of Scientific and Technical Information of China (English)

    SANG; Zunan; XIA; Bin; ZHOU; Yongsheng; JIN; Zhenmin

    2005-01-01

    In this paper, the authors present the results of a preliminary experimental study on partial melting of fine-grained gabbro, Panzhihua, Sichuan Province, China. Experiments were conducted under (confining) pressure ranging from 450 to 500 MPa and temperature of 900-1200℃. The results show that the initial melt is distributed along grain boundaries and triple junctions. Liquid immiscibility phenomena are noted in the melt with two compositional different melt phases, i.e. matrix and sphere phases. The matrix phase is relatively rich in Si, Al and K, and is depleted in Mg, Fe, Ca, Na and Ti, whereas the sphere phase shows opposite trends. The calculation of the melt free energy indicates that the liquid immiscibility is governed by the rule of thermodynamics, as the liquid immiscibility would result in the decrease in free energy of the melt system. The field relationships suggest that the liquid immiscibility may have played an important role in the generation of ore magma of Panzhihua V-Ti magnetite ore deposit. This study thus provides experimental constraints on the mechanism of the formation of V-Ti magnetite deposite.

  15. Preliminaries on pollution risk factors related to mining and ore processing in the Cu-rich pollymetallic belt of Eastern Carpathians, Romania.

    Science.gov (United States)

    Stumbea, Dan

    2013-11-01

    The present study focuses on the mineralogical and geochemical patterns of mining and ore-processing wastes from some occurrences in the Eastern Carpathians; its aim is to identify the main factors and processes that could lead to the pollution of the environment. In this respect, the following types of solid waste were investigated: efflorescent salts developed on the surface of rock blocks from a quarry, ore-processing waste from two tailings ponds, and salt crusts developed at the surface of a tailings pond. The potential risks emphasized by these preliminary investigations are the following: (1) the risk of wind-driven removal and transport of the waste from the surface of tailings ponds, given that fine grains prevail (up to 80%); (2) the risk of tailings removal through mechanical transport by water, during heavy rainfall; (3) the appearance of hydrated sulfates on the rock fragments from the mining waste, sulfates which are highly susceptible to the generation of acid mine drainage (pHmine drainage leachates contain; and (5) the development of a salt crust on the flat, horizontal surfaces of the waste deposit, due to this very shape. Statistical data regarding the amount of both major and minor elements in the tailings have revealed two statistical populations for nearly all the toxic metals. This suggests that, beyond the effect that the tailings have upon the environment through their mere presence in a given area, there are alleged additional factors and processes which intensify the pollution: the location of the waste deposit relative to the topography of the area; the shape of the waste deposit; the development of low areas on the surface of the deposit, areas which favor the appearance of salt crusts; and the mineralogy of efflorescent aggregates.

  16. Contrasting REE Signatures on Manganese Ores of Iron Ore Group in North Orissa, India

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The distribution pattern of Rare Earth Elements (REE) in three categories of manganese ores viz.stratiform, stratabound-replacement, and detrital of Precambrian Iron Ore Group from north Orissa, India was reported.These categories of Mn-ore differed in their major and trace chemistry and exhibited contrasting REE signature.The stratiform ores were relatively enriched in REE content (697 μg·g-1) and their normalized pattern showed both positive Ce and Eu anomalies, whereas the stratabound-replacement types were comparatively depleted in REE content (211 μg·g-1) and showed negative Ce and flat Eu signatures.The detrital categories showed mixed REE pattern.The data plotted in different discrimination diagrams revealed a mixed volcaniclastic and chemogenic source of material for stratiform categories, and LREE (Light Rare Earth Elements) and HREE (Heavy Rare Earth Elements) are contributed by such sources, respectively.In contrast, the stratabound ore bodies were developed during the remobilization of stratiform ores, and associated Mn-containing rocks under supergene condition followed by the redeposition of circulating mineralized colloidal solutions in structurally favorable zones.During this process, some of the constituents were found only in very low concentration within stratabound ores, and this is attributed to their poor leachability/mobility.The detrital ores did not exhibit any significant characteristic in respect of REE as their development was via a complex combination of processes involving weathering, fragmentation, recementation, and burial under soil cover.

  17. Isotopic Characteristics of Mesozoic Au-Ag Polymetallic Ore Deposits in Northern Hebei and Their Ore-Forming Materials Source

    Institute of Scientific and Technical Information of China (English)

    王宝德; 牛树银; 孙爱群; 李红阳

    2003-01-01

    It has long been a controversy about the source of ore-forming materials of Au-Agpolymetallic deposits both in metallogenic theory and in ore-searching practice. In terms of alarge wealth of the isotopic statistics data from Indosinian-Yanshanian endogenic ore deposits innorthern Hebei (generally referring to the areas along the northern part of Taihang Mountainsand northern Hebei, the same below) , it is considered that the ore-forming materials came fromthe deep interior of the Earth, which had migrated through plumes to the Earth surface while ex-perienced multi-stage evolution and then emplaced progressively in favorable structural loci toform ores. Their isotope data show that 559 sulfur isotopic data from 40 ore deposits are, for themost part, within the range of - 5‰ - 5‰, with a high degree of homogenization, indicatingthat the sulfur is derived mainly from magma; 200 lead isotope data from 37 ore deposits indi-cate that the ore-forming materials are principally of mantle source though some crust-source ma-terial was involved; 96 oxygen, hydrogen and carbon isotope data from 34 ore deposits illustratethat the ore-forming fluids are dominated by magmatic water while other sources of water wouldbe involved. It may therefore be seen that the formation of endogenic deposits has nothing to dowith the strata.

  18. PRACTICAL AND PREDICTIVE MODELLING OF ORE DEPOSITS IN HYDROTHERMAL SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chong-bin; B.E.Hobbs; H.B.Muhlhaus; A.Ord

    2001-01-01

    @@ Over the past five years,we have been making efforts to develop a practical and predictive tool to explore for giant ore deposits in hydrothermal systems.Towards this goal,a significant progress has been made towards a better understanding of the basic physical and chemical processes behind ore body formation and mineralization in hydrothermal systems.

  19. PRACTICAL AND PREDICTIVE MODELLING OF ORE DEPOSITS IN HYDROTHERMAL SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Chong-bin; B.E.Hobbs; H.B.Muhlhaus; A.Ord

    2001-01-01

    Over the past five years,we have been making efforts to develop a practical and predictive tool to explore for giant ore deposits in hydrothermal systems.Towards this goal,a significant progress has been made towards a better understanding of the basic physical and chemical processes behind ore body formation and mineralization in hydrothermal systems.……

  20. 铁矿石烧结行业二英类形成机制与排放水平%Formation mechanism and emission profiles of PCDD/Fs in iron ore sintering

    Institute of Scientific and Technical Information of China (English)

    王梦京; 吴素愫; 高新华; 侯梅芳; 唐琛; 刘文彬

    2014-01-01

    Iron ore sintering is one of the important emission sources for PCDD/Fs. This paper summarized formation mechanisms of PCDD/Fs in sintering process and the emission profile of PCDD/Fs in typical sintering stack gas. Key influencing factors of PCDD/Fs formation, including temperature, time, oxygen concentration and other conditions in raw material composition were analyzed. Reduction technologies of PCDD/Fs emission were also suggested in this paper. Finally, it provided analysis and outlook on the current emission of PCDD/Fs from iron ore sintering industry in China and several developed countries. It is aimed to provide reference for the management and reduction of emission of PCDD/Fs in the iron ore sintering industry in China.%铁矿石烧结是我国重要的二英类( PCDD/Fs)排放源之一。本文总结了烧结过程PCDD/Fs的生成机制,以及典型烧结烟气的PCDD/Fs排放特征。针对影响PCDD/Fs生成的关键因素进行了分析,探讨了原料组成中关键元素的影响,以及温度、时间和氧气含量等条件的影响,进而对PCDD/Fs的减排技术等方面进行了讨论。最后本文还对部分发达国家和我国的铁矿石烧结行业PCDD/Fs排放现状进行了分析和展望。可为我国铁矿石烧结行业PCDD/Fs的管理和减排提供参考。

  1. Sedimentary carbonate-hosted giant Bayan Obo REE-Fe-Nb ore deposit of Inner Mongolia, China; a cornerstone example for giant polymetallic ore deposits of hydrothermal origin

    Science.gov (United States)

    Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Tatsumoto, M.; Junwen, Wang; Conrad, J.E.; McKee, E.H.; Zonglin, Hou; Qingrun, Meng; Shengguang, Huang

    1997-01-01

    Detailed, integrative field and laboratory studies of the textures, structures, chemical characteristics, and isotopically determined ages and signatures of mineralization of the Bayan Obo deposit provided evidence for the origin and characteristics favorable for its formation and parameters necessary for defining giant polymetallic deposits of hydrothermal origin. Bayan Obo is an epigenetic, metasomatic, hydrothermal rare earth element (REE)-Fe-Nb ore deposit that is hosted in the metasedimentary H8 dolostone marble of the Middle Proterozoic Bayan Obo Group. The metasedimentary sequence was deposited on the northern continental slope of the North China craton. The mine area is about 100 km south of the suture marking Caledonian subduction of the Mongolian oceanic plate from the north beneath the North China craton. The mineralogy of the deposit is very complex, consisting of more than 120 different minerals, some of which are epigenetic minerals introduced by hydrothermal solutions, and some of which are primary and secondary metamorphic minerals. The major REE minerals are monazite and bastnaesite, whereas magnetite and hematite are the dominant Fe-ore minerals, and columbite is the most abundant Nb mineral. Dolomite, alkali amphibole, fluorite, barite, aegirine augite, apatite, phlogopite, albite, and microcline are the most widespread gangue minerals. Three general types of ores occur at Bayan Obo: disseminated, banded, and massive ores. Broad zoning of these ore types occurs in the Main and East Orebodies. Disseminated ores are in the outermost zone, banded ores are in the intermediate zone, and massive ores are in the cores of the orebodies. On the basis of field relations, host rocks, textures, structures, and mineral assemblages, many varieties of these three types of ores have been recognized and mapped. Isotopic dating of monazite, bastnaesite, aeschynite, and metamorphic and metasomatic alkali amphiboles associated with the deposit provides constraints

  2. Geochemical constraints on the origin of the Kicking Horse and Monarch Mississippi Valley-type lead-zinc ore deposits, southeast British Columbia, Canada

    Science.gov (United States)

    Vandeginste, Veerle; Swennen, Rudy; Gleeson, Sarah A.; Ellam, Rob M.; Osadetz, Kirk; Roure, François

    2007-11-01

    Two Mississippi Valley-type (MVT) ore deposits, Kicking Horse and Monarch, have been studied with the aim of comparing the ores at the two localities and to characterize the origin of the mineralizing fluids and the ore formation process(es). Both deposits are hosted by the Middle Cambrian Cathedral Formation carbonate host rocks, Kicking Horse on the north and Monarch on the south flank of the Kicking Horse valley near Field (SE British Columbia). The ore bodies are situated at the transition of (western) basinal to (eastern) shallow-water strata of the paleo-Pacific passive margin succession in the Cordilleran Foreland Province of the Western Canada Sedimentary Basin. Both deposits are related spatially to normal faults. In both localities, the ore minerals are dominated by pyrite, sphalerite, and galena. Dolomite, minor quartz, and calcite are also present in close association with the ores. The salinity (21-30 wt% NaCl eq.) and homogenization temperatures (63-182°C) measured in fluid inclusions in carbonate, quartz, and sphalerite lie within the typical range of MVT fluid conditions. The good stoichiometry (50-53 mol% CaCO3), low δ18O values (-21 to -14‰ Vienna Peedee belemnite) and relatively high homogenization temperatures (>95°C) of the dolomite suggest the dolomites were formed under burial diagenesis. The ore-forming fluids probably interacted with siliciclastic units, based on elevated Li contents and 87Sr/86Sr ratios, which are highest in the dolomite type after the main ore stage. We propose that the ores formed from the mixing of a downward-infiltrating, sulfur-bearing halite-dissolution fluid with an upward-migrating, metal-rich evaporated seawater fluid, which had already undergone minor mixing with a dilute fluid.

  3. Mechanism of mechanical activation for sulfide ores

    Institute of Scientific and Technical Information of China (English)

    HU Hui-ping; CHEN Qi-yuan; YIN Zhou-lan; HE Yue-hui; HUANG Bai-yun

    2007-01-01

    Structural changes for mechanically activated pyrite, sphalerite, galena and molybdenite with or without the exposure to ambient air, were systematically investigated using X-ray diffraction analysis(XRD), particle size analysis, gravimetrical method, X-ray photo-electron spectroscopy(XPS) and scanning electron microscopy(SEM), respectively. Based on the above structural changes for mechanically activated sulfide ores and related reports by other researchers, several qualitative rules of the mechanisms and the effects of mechanical activation for sulfide ores are obtained. For brittle sulfide ores with thermal instability, and incomplete cleavage plane or extremely incomplete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with thermal instability, and complete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed, and lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with excellent thermal stability, and complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For sulfide ores with high toughness, good thermal stability and very excellent complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation, but the lattice deformation ratio is very small. The effects of mechanical activation are worst.

  4. Terrestrial ferromanganese ore concentrations from mid-european basement blocks and their implication concerning the environment of formation during the late cenozoic (northern Bavaria, F.R.G.)

    Science.gov (United States)

    Dill, Harald

    1985-10-01

    Terrestrial Fe-Mn concentrations from the Hercynian Basement in Central Europe may be categorized into five principal types: ferricretes sensu stricto, pebble iron ores, ferruginous conglomerates and breccias (Fe-Mn cement), Fe replacement ores and limonitic gossans of vein-type deposits. The four types first mentioned are true supergene, whereas the last-mentioned type of Fe-Mn mineralization is suggested to have been generated by ascending hydrothermal fluids which reacted with ground waters. A sequence of minerals common to all the different host-rock lithologies may be established: Fe silcretes, goethite, poorly hydrated Mn oxides and intensively hydrated modifications of manganomelane. The Fe-Mn enrichments, irrespective of their host rocks, were taken as remnants of hydromorphic paleosoils of nonlateritic origin (Plio-Pleistocene). The more silicified equivalents are assumed to be precursor of these concretions. The most significant controls on Fe-Mn enrichments are considered to be the host-rock lithology, the local and regional geomorphology and the Cenozoic climatic conditions.

  5. Aluminum substitution in goethite in lake ore

    Directory of Open Access Journals (Sweden)

    Carlson, L.

    1995-06-01

    Full Text Available The extent of substitution of Fe by Al in goethite in 32 lake ore samples collected from 11 lakes in Finland varied between 0 and 23 mol-%. The data indicated a negative relationship between Al-substitution and the particle size of lake ore. Differences in the Al-substitution were apparent between sampling sites, suggesting that kinetic and environmental variation in lake ore formation influences the substitution. Non-substituted goethite is formed in coarse-grained sediments with locally high concentrations of Fe due to iron-rich springs. Unit cell edge lengths and volumes of goethite varied as function of Al-subsitution but deviated from the Vegard relationship towards higher values.

  6. By lithology Zbruch deposits (Lower Sarmatian Nikopol manganese ore Basin

    Directory of Open Access Journals (Sweden)

    Bogdanovich V.V.

    2010-06-01

    Full Text Available Based on lithologic-paleogeographic study Zbruch layers of Nikopol manganese ore Basin sediments described lithological and genetic types of rocks and facies conditions of formation of deposits.

  7. Promoting proximal formative assessment with relational discourse

    Science.gov (United States)

    Scherr, Rachel E.; Close, Hunter G.; McKagan, Sarah B.

    2012-02-01

    The practice of proximal formative assessment - the continual, responsive attention to students' developing understanding as it is expressed in real time - depends on students' sharing their ideas with instructors and on teachers' attending to them. Rogerian psychology presents an account of the conditions under which proximal formative assessment may be promoted or inhibited: (1) Normal classroom conditions, characterized by evaluation and attention to learning targets, may present threats to students' sense of their own competence and value, causing them to conceal their ideas and reducing the potential for proximal formative assessment. (2) In contrast, discourse patterns characterized by positive anticipation and attention to learner ideas increase the potential for proximal formative assessment and promote self-directed learning. We present an analysis methodology based on these principles and demonstrate its utility for understanding episodes of university physics instruction.

  8. An evaporated seawater origin for the ore-forming brines in unconformity-related uranium deposits (Athabasca Basin, Canada): Cl/Br and δ 37Cl analysis of fluid inclusions

    Science.gov (United States)

    Richard, Antonin; Banks, David A.; Mercadier, Julien; Boiron, Marie-Christine; Cuney, Michel; Cathelineau, Michel

    2011-05-01

    Analyses of halogen concentration and stable chlorine isotope composition of fluid inclusions from hydrothermal quartz and carbonate veins spatially and temporally associated with giant unconformity-related uranium deposits from the Paleoproterozoic Athabasca Basin (Canada) were performed in order to determine the origin of chloride in the ore-forming brines. Microthermometric analyses show that samples contain variable amounts of a NaCl-rich brine (Cl concentration between 120,000 and 180,000 ppm) and a CaCl 2-rich brine (Cl concentration between 160,000 and 220,000 ppm). Molar Cl/Br ratios of fluid inclusion leachates range from ˜100 to ˜900, with most values between 150 and 350. Cl/Br ratios below 650 (seawater value) indicate that the high salinities were acquired by evaporation of seawater. Most δ 37Cl values are between -0.6‰ and 0‰ (seawater value) which is also compatible with a common evaporated seawater origin for both NaCl- and CaCl 2-rich brines. Slight discrepancies between the Cl concentration, Cl/Br, δ 37Cl data and seawater evaporation trends, indicate that the evaporated seawater underwent secondary minor modification of its composition by: (i) mixing with a minor amount of halite-dissolution brine or re-equilibration with halite during burial; (ii) dilution in a maximum of 30% of connate and/or formation waters during its migration towards the base of the Athabasca sandstones; (iii) leaching of chloride from biotites within basement rocks and (iv) water loss by hydration reactions in alteration haloes linked to uranium deposition. The chloride in uranium ore-forming brines of the Athabasca Basin has an unambiguous dominantly marine origin and has required large-scale seawater evaporation and evaporite deposition. Although the direct evidence for evaporative environments in the Athabasca Basin are lacking due to the erosion of ˜80% of the sedimentary pile, Cl/Br ratios and δ 37Cl values of brines have behaved conservatively at the basin

  9. Mantle Branch Structure in the South-Central Segment of the Da Hinggan Mts., Inner Mongolia and Its Ore-controlling Role

    Institute of Scientific and Technical Information of China (English)

    NIU Shuyin; SUN Aiqun; WANG Baode; NIE Fengjun; JIANG Sihong; SHAO Jian; GUO Lijun; LIU Jianming

    2009-01-01

    Mantle branch structure is the third tectonic unit of multiple evolution of a mantle branch. It is not only the main mechanism of intercontinental orogeny, but also an important ore-forming and ore-control structure. Studies on geotectonic evolution, regional geological characteristics and ore-forming and ore-control structures have shown that since the Mesozoic the Da Hinggan Mts. region has entered a typical intercontinental orogenic stage, and it is closely related to mantle branch activities. The south-central segment of the Da Hinggan Mts. is a typical mantle branch structure and possesses obvious magmatic-metamorphic complexes in the core, detachment slip beds in the periphery and overlapped fault depression basins. Moreover, all of these are the principal factors leading to ore formation and ore control in the region. This paper also further explores the mechanism of mineralization in the south-central segment of the Da Hinggan, summaries the rules of mineralization, puts forward the models of mineralization and points out future ore-exploring orientation.

  10. A study of the distribution of rare-metals in kuroko-type ore

    Energy Technology Data Exchange (ETDEWEB)

    Murao, S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience]|[Geological Survey of Japan, Tsukuba, Ibaraki (Japan); Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1996-12-31

    We have performed PIXE analysis of kuroko-type ore from the JADE hydrothermal site of the Okinawa Trough, Japan using the proton microprobe (PIXEPROBE). We analysed five kinds of ores dredged from the sea floor: (I) barite ore with small sulfide dissemination; (2) sphalerite-pyrite chimney; (3) pyrite ore; (4) sulfide veinlets in strongly altered rock; and (5) pyrite megacrystals in strongly altered rock. The analyses revealed that the trace element distribution is regulated by the occurrence mode of the ore, and within each ore, by the crystal structure. The distribution suggests that the hydrothermal system for kuroko ore formation is quite heterogeneous and its chemistry is controlled by local factors such as difference in temperature, and that in-situ PIXE analyses are essential for effective beneficiation strategy for the rare-metals from kuroko-type ore. (authors). 10 refs., 1 tab.

  11. Transport of Pb and Zn by carboxylate complexes in basinal ore fluids and related petroleum-field brines at 100°C: the influence of pH and oxygen fugacity

    Directory of Open Access Journals (Sweden)

    Giordano Thomas H

    2002-09-01

    Full Text Available It is well established through field observations, experiments, and chemical models that oxidation (redox state and pH exert a strong influence on the speciation of dissolved components and the solubility of minerals in hydrothermal fluids. log –pH diagrams were used to depict the influence of oxygen fugacity and pH on monocarboxylate- and dicarboxylate-transport of Pb and Zn in low-temperature (100°C hydrothermal ore fluids that are related to diagenetic processes in deep sedimentary basins, and allow a first-order comparison of Pb and Zn transport among proposed model fluids for Mississippi Valley-type (MVT and red-bed related base metal (RBRBM deposits in terms of their approximate pH and conditions. To construct these diagrams, total Pb and Zn concentrations and Pb and Zn speciation were calculated as a function of log and pH for a composite ore-brine with concentrations of major elements, total sulfur, and total carbonate that approximate the composition of MVT and RBRBM model ore fluids and modern basinal brines. In addition to acetate and malonate complexation, complexes involving the ligands Cl-, HS-, H2S, and OH- were included in the model of calculated total metal concentration and metal speciation. Also, in the model, Zn and Pb are competing with the common-rock forming metals Ca, Mg, Na, Fe, and Al for the same ligands. Calculated total Pb concentration and calculated total Zn concentration are constrained by galena and sphalerite solubility, respectively. Isopleths, in log –pH space, of the concentration of Pb and concentration of Zn in carboxylate (acetate + malonate complexes illustrate that the oxidized model fluids of T. H. Giordano (in Organic Acids in Geological Processes, ed. E. D. Pittman and M. D. Lewan, Springer-Verlag, New York, 1994, pp. 319–354 and G. M. Anderson (Econ. Geol., 1975, 70, 937–942 are capable of transporting sufficient amounts of Pb (up to 10 ppm and Zn (up to 100 ppm in the form of carboxylate

  12. Sedimentary exhalative nickel-molybdenum ores in south China

    Science.gov (United States)

    Lott, D.A.; Coveney, R.M.; Murowchick, J.B.; Grauch, R.I.

    1999-01-01

    Unique bedded Ni-Mo ores hosted by black shales were discovered in localized paleobasins along the Yangzte platform of southern China in 1971. Textural evidence and radiometric dates imply ore formation during sedimentation of black shales that grade into readily combustible beds, termed stone coals, which contain 10 to 15 percent organic carbon. Studies of 427 fluid inclusions indicate extreme variation in hydrothermal brine salinities that were contained by Proterozoic dolostones underlying the ore zone in Hunan and Guizhou. Variations of fluid inclusion salinities, which range from 0.1 to 21.6 wt percent NaCl equiv, are attributed to differences in the compositions of brines in strata underlying the ore bed, complicated by the presence of seawater and dilute fluids that represent condensates of vapors generated by boiling of mineralizing fluids or Cambrian meteoric water. The complex processes of ore deposition led to scattered homogenization temperatures ranging from 100??to 187??C within the Hunan ore zone and from 65??to 183??C within the Guizhou ore zone. While living organisms probably did not directly accumulate metals in situ in sufficient amounts to explain the unusually high grades of the deposits, sulfur isotope ratios indicate that bacteria, now preserved as abundant microfossils, provided sufficient sulfide for the ores by reduction of seawater sulfate. Such microbiota may have depended on vent fluids and transported organic matter for key nutrients and are consistent with a sedex origin for the ores. Vent fluids interacted with organic remains, including rounded fragments of microbial mats that were likely transported to the site of ore deposition by the action of waves and bottom currents prior to replacement by ore minerals.

  13. The physical hydrogeology of ore deposits

    Science.gov (United States)

    Ingebritsen, Steven E.; Appold, M.S.

    2012-01-01

    Hydrothermal ore deposits represent a convergence of fluid flow, thermal energy, and solute flux that is hydrogeologically unusual. From the hydrogeologic perspective, hydrothermal ore deposition represents a complex coupled-flow problem—sufficiently complex that physically rigorous description of the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes (THMC modeling) continues to challenge our computational ability. Though research into these coupled behaviors has found only a limited subset to be quantitatively tractable, it has yielded valuable insights into the workings of hydrothermal systems in a wide range of geologic environments including sedimentary, metamorphic, and magmatic. Examples of these insights include the quantification of likely driving mechanisms, rates and paths of fluid flow, ore-mineral precipitation mechanisms, longevity of hydrothermal systems, mechanisms by which hydrothermal fluids acquire their temperature and composition, and the controlling influence of permeability and other rock properties on hydrothermal fluid behavior. In this communication we review some of the fundamental theory needed to characterize the physical hydrogeology of hydrothermal systems and discuss how this theory has been applied in studies of Mississippi Valley-type, tabular uranium, porphyry, epithermal, and mid-ocean ridge ore-forming systems. A key limitation in the computational state-of-the-art is the inability to describe fluid flow and transport fully in the many ore systems that show evidence of repeated shear or tensional failure with associated dynamic variations in permeability. However, we discuss global-scale compilations that suggest some numerical constraints on both mean and dynamically enhanced crustal permeability. Principles of physical hydrogeology can be powerful tools for investigating hydrothermal ore formation and are becoming increasingly accessible with ongoing advances in modeling software.

  14. Effects of Mineral Composition and Microstructure on Crack Resistance of Sintered Ore

    Institute of Scientific and Technical Information of China (English)

    YING Zi-wei; JIANG Mao-fa; XU Li-xian

    2006-01-01

    Vickers indentation test was used to study the effects of mineral composition and microstructure on crack resistance of sintered ore, and the initiation and propagation of cracks in different minerals contained in sintered ore were examined. The results indicate that the microstructure of calcium ferrites is a major factor influencing crack resistance of sintered ore. Finer grain size of calcium ferrite will lead to higher cracking threshold and better crack resistance of sintered ore. The formation of calcium ferrite with fine grain size during sintering process is favorable for crack resistance of sintered ore.

  15. Trace element geochemistry of zircons from mineralizing and non-mineralizing igneous rocks related to gold ores at Yanacocha, Peru

    Science.gov (United States)

    Koleszar, A. M.; Dilles, J. H.; Kent, A. J.; Wooden, J. L.

    2012-12-01

    Zircons record important details about the evolution of magmatic systems, are relatively insensitive to alteration, and have been used to investigate the geochemistry, temperature, and oxidation state of volcanic and plutonic system. We examine zircons that span 6-7 m.y. of calc-alkaline volcanic activity in the Yanacocha district of northern Peru, where dacitic intrusions are associated with high-sulfidation gold deposits. The 14.5-8.4 Ma Yanacocha Volcanics include cogenetic lavas and pyroclastic rocks and are underlain by the andesites and dacites of the Calipuy Group, the oldest Cenozoic rocks in the region. We present data for magmatic zircons from the Cerro Fraile dacitic pyroclastics (15.5-15.1 Ma) of the Calipuy Group, and multiple eruptive units within the younger Yanacocha Volcanics: the Atazaico Andesite (14.5-13.3 Ma), the Quilish Dacite (~14-12 Ma), the Azufre Andesite (12.1-11.6 Ma), the San Jose Ignimbrite (11.5-11.2 Ma), and the Coriwachay Dacite (11.1-8.4 Ma). Epithermal high sulfidation (alunite-bearing) gold deposits are associated with the dacite intrusions of the Coriwachay and Quilish Dacites. Zircons from the non-mineralizing rocks typically have lower Hf concentrations and record Ti-in-zircon temperatures that are ~100°C hotter than zircons from the mineralizing intrusions. Temperatures recorded by zircons from the mineralizing intrusions are remarkably similar to those of the underlying Cerro Fraile dacite pyroclastics, but the zircons discussed here generally record SHRIMP-RG 206Pb/238U ages within error of previously published Ar-Ar eruption ages (eliminating antecrystic or xenocrystic origins). These observations suggest that zircons in the mineralizing intrusions form after greater extents of crystallization (and thus record elevated Hf concentrations and lower temperatures) than do zircons in the non-mineralized deposits. Unlike zircons from mineralized units associated with the porphyry Cu(Mo) deposits in Yerington, Nevada, which

  16. Ore-forming mechanism for the Xiaoxinancha Au-rich Cu deposit in Yanbian, Jilin Province, China: Evidence from noble gas isotope geochemistry of fluid inclusions in minerals

    Institute of Scientific and Technical Information of China (English)

    SUN JingGui; ZHAO JunKang; CHEN JunQiang; KEISUKE Nagao; HIROCHiKA Sumino; SHEN Kun; MEN LanJing; CHEN Lei

    2008-01-01

    The Xiaoxinancha Au-rich copper deposit is one of important Au-Cu deposits along the continental margin in Eastern China. The deposit consists of two sections: the Beishan mine (North), composed of altered rocks with veinlet-dissemination sulfides and melnicovite-dominated sulfide-quartz veins, and the Nanshan mine (South), composed of pyrrhotite-dominated sulfide-quartz veins and pure sulfide veins. The isotope compositions of noble gases extracted from fluid inclusions in ore minerals, i.e. ratios of 3He/4He, 20Ne/22Ne and 40Ar/36Ar are in the ranges of 4.45-0.08 Ra, 10.2-8.8 and 306-430, respectively. Fluid inclusions in minerals from the Nanshan mine have higher 3He/4He and 20Ne/22Ne ratios whereas those from the Beishan mine have lower 3He/4He ratios. The analysis of origin, and evolution of the ore fluids and its relations with the ore-forming stages and the ages of mineralization suggests that the initial hydrothermal fluids probably come from the melts generated by partial melting of oceanic crust with the participation of fluids from the mantle (mantle-plume type)/aesthenosphere. This also corresponds to the continental margin settings during the subduction of Izanagi ocaneic plate towards the palaeo-Asian continent (123-102 Ma). The veinlet-dissemination ore bodies of the Beishan mine were formed through replacement and crystallization of the mixed fluids generated by mixing of the ascending high-temperature boiling fluid with young crustal fluid whereas the melnicovite-dominated sulfide-quartz veins were formed subsequently by filling of the high-temperature ore fluid in fissures. Pyrrhotite-dominated sulfide-quartz veins in the Nanshan mine were formed by filling-deposition- crystallization of the moderate-temperature ore fluids and the pure sulfide veins were formed later by filling-deposition-crystallization of ore substance-rich fluids after boiling of the moderate-temperature ore fluids. The metallogenic dynamic processes can be summarized as: (1

  17. NUMERICAL EVALUATION OF THE EFFECTS OF SOFT-MELTING PROPERTIES ON THE KINETIC OF (CAFE2 O4 -CA2 FE2 O5 FORMATION IN THE IRON ORE SINTERING PROCESS

    Directory of Open Access Journals (Sweden)

    José Adilson de Castro

    2013-03-01

    Full Text Available This paper presents a mathematical model able to predict the influence of soft-melting properties of the blend of raw materials used in the iron ore sintering process in the kinetic formation of calcium ferrite and di-calcium ferrite constituents. The model is based on the simultaneous solution of transport equations of Momentum, energy and chemical species in multiphase multicomponent systems coupled with the chemical reactions kinetics and phase transformations that occur within the sinter bed. The numerical solution is obtained using the finite volume method and the model is validated using monitoring data from an industrial scale sintering plant. After validation, the model was used to predict processing conditions using raw materials with different soft-melting properties. Results indicate that the temperatures of starting soft-melting, shrinkage and melting range are the main parameters to be controlled in order to attain liquid phases formation responsible to confer good mechanical and reducibility properties for the sinter product. In this study was found that raw materials with high soft-melting temperature and wilder temperature of mushy zone could decrease up to 30% the calcium ferrites formation and hence deteriorates the metallurgical properties of the sinter.

  18. A Cautionary Note about Composite Galactic Star Formation Relations

    Science.gov (United States)

    Parmentier, G.

    2016-07-01

    We explore the pitfalls that affect the comparison of the star formation relation for nearby molecular clouds with that for distant compact molecular clumps. We show that both relations behave differently in the ({{{Σ }}}{{gas}}, {{{Σ }}}{{SFR}}) space, where {{{Σ }}}{{gas}} and {{{Σ }}}{{SFR}} are, respectively, the gas and star formation rate surface densities, even when the physics of star formation is the same. This is because the star formation relation of nearby clouds relates the gas and star surface densities measured locally, that is, within a given interval of gas surface density, or at a given protostar location. We refer to such measurements as local measurements, and the corresponding star formation relation as the local relation. In contrast, the stellar content of a distant molecular clump remains unresolved. Only the mean star formation rate can be obtained, e.g., from the clump infrared luminosity. One clump therefore provides one single point to the ({{{Σ }}}{{gas}}, {{{Σ }}}{{SFR}}) space, that is, its mean gas surface density and star formation rate surface density. We refer to this star formation relation as a global relation since it builds on the global properties of molecular clumps. Its definition therefore requires an ensemble of cluster-forming clumps. We show that although the local and global relations have different slopes, this cannot per se be taken as evidence for a change in the physics of star formation with gas surface density. It therefore appears that great caution should be taken when physically interpreting a composite star formation relation, that is, a relation combining local and global relations.

  19. Mineralogy and trace-element geochemistry of the high-grade iron ores of the Águas Claras Mine and comparison with the Capão Xavier and Tamanduá iron ore deposits, Quadrilátero Ferrífero, Brazil

    Science.gov (United States)

    Spier, Carlos Alberto; de Oliveira, Sonia Maria Barros; Rosière, Carlos Alberto; Ardisson, José Domingos

    2008-02-01

    Tamanduá orebodies shows that the original composition of the itabiritic protore plays a major role in the genesis of high- and low-grade soft ores in the QF. Under the same weathering and structural conditions, the dolomitic itabirite is the more favorable to form high-grade deposits than siliceous itabirite. Field relations at the Águas Claras and Capão Xavier deposits suggest that it is not possible to form huge soft high-grade supergene deposits from siliceous itabirite, unless another control, such as impermeable barriers, had played an important role. The occurrence in the Tamanduá Mine of a large, soft, high-grade orebody formed from siliceous itabirite and closely associated with hypogene hard ore suggests that large, soft, high-grade orebodies of the Quadrilátero Ferrífero, which occur within siliceous itabirite, have a hypogene contribution in their formation.

  20. HANDLING, STORAGE AND IRON ORE QUALITY

    Directory of Open Access Journals (Sweden)

    Fabiana Fonseca Fortes

    2012-06-01

    Full Text Available This paper aims to identify handling and storage impact in iron ore quality, in their physical and chemical characteristics most important for a mining. It is tried to show the interferences in iron ore quality caused by the handling equipment and stockpiling. The research is restricted to Complexo Vargem Grande (Vale. The timeline was demarcated based on the formation of stockpiling. The fieldwork enables data collection and distinction of the routine procedures of casual operations handling. The quantitative analysis is conducted by the statistical method. As a conclusion, handling and storage identified are able to insert changes in physical and chemical characteristics of iron ore. Storage contributes to reduce variability of silica and alumina concentrations, but contributes too particle size deterioration. The handling induces degradation and segregation. However, there is the possibility to decrease handling of the ore and to establish the ideal size of stocks on the system in study, improving the efficiency of the system and consequent in global costs.

  1. Chemical fingerprint of iron oxides related to iron enrichment of banded iron formation from the Cauê Formation - Esperança Deposit, Quadrilátero Ferrífero, Brazil: a laser ablation ICP-MS study

    National Research Council Canada - National Science Library

    Oliveira, Lucilia Aparecida Ramos de; Rosière, Carlos Alberto; Rios, Francisco Javier; Andrade, Sandra; Moraes, Renato de

    2015-01-01

    ... Formation from Minas Supergroup. Variations of Mn, Mg and Sr content in different generations of iron oxides from dolomitic itabirite, high-grade iron ore and syn-mineralization quartz-carbonate-hematite veins denote the close...

  2. Sources of ores of the ferroalloy metals

    Science.gov (United States)

    Burchard, E.F.

    1933-01-01

    Since all steel is made with the addition of alloying elements, the record of the metallic raw materials contributory to the steel industry would be far from complete without reference to the ferroalloy metals. This paper, therefore, supplements two preceding arvicles on the sources of our iron ores. The photographs, with the exception of those relating to molybdenum and vanadium, are by the author.

  3. Target-related neologism formation in jargonaphasia.

    Science.gov (United States)

    Christman, S S

    1994-01-01

    Neologistic demisyllables produced by three subjects with jargonaphasia (Christman, 1990, 1992) were compared to target demisyllables to determine whether phonological patterns underlying target-related neology could be captured by the Sonority Sequencing Principle independently of phonotactics. Results revealed that substitution errors replaced most intended segments with obstruents, despite the absence of phonotactic restrictions that might have conditioned the errors. Findings suggest a default pattern of segment selection to which the phonological system reverts when normal processing is otherwise blocked.

  4. Sulfur isotope geochemistry of ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type ore district, Poland

    Science.gov (United States)

    Leach, D.L.; Vets, J.G.; Gent, C.A.

    1996-01-01

    Studies of the sulfur isotopic composition of ore and gangue minerals from the Silesian-Cracow Zn-Pb district were conducted to gain insights into processes that controlled the location and distribution of the ore deposits. Results of this study show that minerals from the Silesian-Cracow ore district have the largest range of sulfur isotope compositions in sulfides observed from any Mississippi Valley-type ore district in the world. The ??34S values for sulfide minerals range from +38 to -32 per mil for the entire paragenetic sequence but individual stages exhibit smaller ranges. There is a well developed correlation between the sulfur isotope composition and paragenetic stage of ore deposition. The first important ore stage contains mostly positive ??34S values, around 5 per mil. The second stage of ore formation are lower, with a median value of around -5 to -15 per mil, and with some values as low as -32 per mil. Late stage barite contains isotopically heavy sulfur around +32 per mil. The range in sulfur isotope compositions can be explained by contributions of sulfur from a variety of source rocks together with sulfur isotope fractionations produced by the reaction paths for sulfate reduction. Much of the variation in sulfur isotope compositions can be explained by bacterial reduction of sedimentary sulfate and disequilibrium reactions by intermediate-valency sulfur species, especially in the late-stage pyrite and sphalerite. Organic reduction of sulfate and thermal release of sulfur from coals in the Upper Silesian Coal Basin may have been important contributors to sulfur in the ore minerals. The sulfur isotopic data, ore mineral textures, and fluid inclusion data, are consistent with the hypothesis that fluid mixing was the dominant ore forming mechanism. The rather distinct lowering of ?? 34S values in sulfides from stage 2 to stage 3 is believed to reflect some fundamental change in the source of reduced sulfur and/or hydrology of the ore

  5. Excited response of granular ores in vibrating field

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The dynamical theory was utilized to probe into the law of the excited response of granular ores generated by the exciting action of exciter and the influence of wave propagation in vibrating field. The exciter with double axes was presented as an example, and the principle of exciter and its mathematical expression of the excitation force were given. The granular ores have viscidity and damping speciality, on the basis of which the motion equation of excited response of ores was established and the approximate expression of mode-displacement by harmonic excitation and the steady effect solution of coordinate response were deduced. Utilizing the step-by-step integration method, the recursion relation matrix of displacement, velocity and acceleration of the excited response of ores were obtained, and the computational flow chart and a computational example were given. The results show that the excited response can change the dynamical character and the flowing characteristic of granular ores.

  6. : Didactic interaction(s), Formative relation

    OpenAIRE

    Bretegnier, Aude

    2010-01-01

    Cette réflexion s'inscrit dans le cadre plus large de recherches qui portent sur la construction de l'expérience et des rapports aux langues et aux normes, notamment dans des espaces de pluralité linguistique inégalitaire (Bretegnier, 2002, 2005). D'un point de vue didactique, ces travaux explorent la question des liens entre les pratiques d'apprentissages et les relations construites à la langue française, par des apprenants en double difficulté de langue et d'insertion sociale (migrants, pe...

  7. Complexing and hydrothermal ore deposition

    CERN Document Server

    Helgeson, Harold C

    1964-01-01

    Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

  8. 熔体包裹体在估算花岗岩类矿床形成压力(深度)方面的应用%Application of melt inclusions to estimating ore-forming pressure (depth) of granite-related ore deposits

    Institute of Scientific and Technical Information of China (English)

    李建康; 张德会; 李胜虎

    2011-01-01

    在花岗岩类矿床中,花岗岩浆分异出富挥发分熔体/流体的过程,是导致岩浆就位和成矿元素迁移、富集的关键因素之一.在该过程中,同时捕获的不同类别的熔体包裹体和流体包裹体可以互相限定捕获条件,由此可以建立一系列与熔体包裹体有关的地质压力计,进而得到相关分异作用发生的深度.这些深度数值,对于指导花岗岩地区的找矿工作具有重要价值.与熔体包裹体有关的压力计主要分为与硅酸盐熔体包裹体共生的流体包裹体地质压力计、硅酸盐熔体包裹体地质压力计和富子晶包裹体地质压力计.这些压力计使用的难点主要是均一实验,实验设备主要有Linkam高温热台系统、冷封式高压釜和热液金刚石压腔,三者各有优缺点.国内许多实验室已经具备开展熔体包裹体均一实验的条件.在中国,如南岭地区,许多花岗岩类矿床中存在花岗岩晶洞、花岗岩中的似伟晶岩囊体、花岗岩与围岩接触带的似伟晶岩壳、花岗伟晶岩以及富挥发分花岗岩,这些地质体保留了熔体分异出富挥发分熔体/流体的痕迹,是应用与熔体包裹体有关的压力计的良好对象.%In the granite-related ore deposits, the differentiation of volatile-rich melt or fluid from granitic magma constitutes one of the key factors controlling the emplacement depth as well as the migration and enrichment of ore-forming elements. In these processes, the coexisting melt and fluid inclusions can mutually constrain entrapment conditions, and then a series of geobarometers can be induced. The depth estimated by such barometers represents differentiation that occurred and can help ore exploration work in granite areas. These barometers include methods of fluid inclusions coexisting with melt inclusions, melt inclusions and crystal-rich inclusions. The main difficulty in application of these barometers is the melt inclusion microthermometry. At

  9. Behavior of uranium under conditions of interaction of rocks and ores with subsurface water

    Science.gov (United States)

    Omel'Yanenko, B. I.; Petrov, V. A.; Poluektov, V. V.

    2007-10-01

    The behavior of uranium during interaction of subsurface water with crystalline rocks and uranium ores is considered in connection with the problem of safe underground insulation of spent nuclear fuel (SNF). Since subsurface water interacts with crystalline rocks formed at a high temperature, the mineral composition of these rocks and uranium species therein are thermodynamically unstable. Therefore, reactions directed toward the establishment of equilibrium proceed in the water-rock system. At great depths that are characterized by hindered water exchange, where subsurface water acquires near-neutral and reducing properties, the interaction is extremely sluggish and is expressed in the formation of micro- and nanoparticles of secondary minerals. Under such conditions, the slow diffusion redistribution of uranium with enrichment in absorbed forms relative to all other uranium species is realized as well. The products of secondary alteration of Fe- and Ti-bearing minerals serve as the main sorbents of uranium. The rate of alteration of minerals and conversion of uranium species into absorbed forms is slow, and the results of these processes are insignificant, so that the rocks and uranium species therein may be regarded as unaltered. Under reducing conditions, subsurface water is always saturated with uranium. Whether water interacts with rock or uranium ore, the equilibrium uranium concentration in water is only ≤10-8 mol/l. Uraninite ore under such conditions always remains stable irrespective of its age. The stability conditions of uranium ore are quite suitable for safe insulation of SNF, which consists of 95% uraninite (UO2) and is a confinement matrix for all other radionuclides. The disposal of SNF in massifs of crystalline rocks at depths below 500 m, where reducing conditions are predominant, is a reliable guarantee of high SNF stability. Under oxidizing conditions of the upper hydrodynamic zone, the rate of interaction of rocks with subsurface water

  10. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-06-01

    Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

  11. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-03-01

    Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

  12. Remobilisation features and structural control on ore grade distribution at the Konkola stratiform Cu-Co ore deposit, Zambia

    Science.gov (United States)

    Torremans, K.; Gauquie, J.; Boyce, A. J.; Barrie, C. D.; Dewaele, S.; Sikazwe, O.; Muchez, Ph.

    2013-03-01

    The Konkola deposit is a high grade stratiform Cu-Co ore deposit in the Central African Copperbelt in Zambia. Economic mineralisation is confined to the Ore Shale formation, part of the Neoproterozoic metasedimentary rocks of the Katanga Supergroup. Petrographic study reveals that the copper-cobalt ore minerals are disseminated within the host rock, sometimes concentrated along bedding planes, often associated with dolomitic bands or clustered in cemented lenses and in layer-parallel and irregular veins. The hypogene sulphide mineralogy consists predominantly of chalcopyrite, bornite and chalcocite. Based upon relationships with metamorphic biotite, vein sulphides and most of the sulphides in cemented lenses were precipitated during or after biotite zone greenschist facies metamorphism. New δ34S values of sulphides from the Konkola deposit are presented. The sulphur isotope values range from -8.7‰ to +1.4‰ V-CDT for chalcopyrite from all mineralising phases and from -4.4‰ to +2.0‰ V-CDT for secondary chalcocite. Similarities in δ34S for sulphides from different vein generations, earlier sulphides and secondary chalcocite can be explained by (re)mobilisation of S from earlier formed sulphide phases, an interpretation strongly supported by the petrographic evidence. Deep supergene enrichment and leaching occurs up to a km in depth, predominantly in the form of secondary chalcocite, goethite and malachite and is often associated with zones of high permeability. Detailed distribution maps of total copper and total cobalt contents of the Ore Shale formation show a close relationship between structural features and higher copper and lower cobalt contents, relative to other areas of the mine. Structural features include the Kirilabombwe anticline and fault zones along the axial plane and two fault zones in the southern limb of the anticline. Cobalt and copper behave differently in relation to these structural features. These structures are interpreted to have

  13. High-grade iron ore at Windarling, Yilgarn Craton: a product of syn-orogenic deformation, hypogene hydrothermal alteration and supergene modification in an Archean BIF-basalt lithostratigraphy

    Science.gov (United States)

    Angerer, Thomas; Hagemann, Steffen G.; Danyushevsky, Leonid

    2013-08-01

    Banded iron formation (BIF)-hosted iron ore deposits in the Windarling Range are located in the lower greenstone succession of the Marda-Diemals greenstone belt, Southern Cross domain, Yilgarn Craton and constitute a total hematite-martite-goethite ore resource of minimum 52 Mt at 60 wt.% Fe (0.07 P). Banded iron formation is interlayered with high-Mg basalts at Windarling and precipitated during episodes of volcanic quiescence. Trace element content and the rare earth element (REE) ratios Y/Ho (42 to 45), Sm/Yb (1.5), together with positive La and Gd anomalies in `least-altered' hematite-magnetite-metachert-BIF indicate the precipitation from Archean seawater that was fertilised by hydrothermal vent fluids with a basaltic HREE-Y signature. Hypogene iron ore in sub-greenschist facies metamorphosed BIF formed during three distinct stages: ore stage 1 was a syn- to post-metamorphic, syn-D1, Fe-Ca-Mg-Ni-Co-P-REE metasomatism that produced local Ni-REE-rich Fe-dolomite-magnetite alteration in BIF. Hydrothermal alteration was induced by hot fluid flow controlled by brittle-ductile reactivation of BIF-basalt margins and crosscutting D1 faults. The Ni-Co-rich content of dolomite and a shift in REE ratios in carbonate-altered BIF towards Archean mafic rock signature (Y/Ho to 31 to 40, Sm/Yb to 1 to 2 and Gd/Gd* to 1.2 to 1.4) suggest that high-Mg basalts in the Windarling Range were the primary source of introduced metals. During ore stage 2, a syn-deformational and likely acidic and oxidised fluid flow along BIF-basalt margins and within D1 faults leached carbonate and precipitated lepidoblastic and anhedral/granoblastic hematite. High-grade magnetite-hematite ore is formed during this stage. Ore stage 3 hydrothermal specular hematite (spcH)-Fe-dolomite-quartz alteration was controlled by a late-orogenic, brittle, compressional/transpressional stage (D4; the regional-scale shear-zone-related D3 is not preserved in Windarling). This minor event remobilised iron oxides

  14. 川南地区石宝矿段龙潭组层序地层研究%sequence stratigraphy of the Longtan formation in the Shibao ore block of South Sichuan

    Institute of Scientific and Technical Information of China (English)

    刘安然; 巫晓兵; 胡俊仁

    2014-01-01

    Upper Permian Longtan Formation coal-bearing strata in southern Sichuan region is characterized by the depth and thickness variation .Guided by the theories and methods of the Sedimentary petrology and sequence stratigraphy ,through consolidated results of previous studies ,the authors divided the Upper Permian Longtan Formation in the Shibao ore block of South Sichuan into 3 long-term sequence (LSC1-LSC3) and many medium-term sequences through comprehensive study of outcrops ,coring ,logging and seismic data . According to the identified four kinds of sequence boundary and its manifestations substances , including regional unconformity , fluvial erosion surface , lithology , lithofacies conversion surface and maximum flooding surface ,the long-term base-level cycles in each cycle of the material change and mechanism of coal accumulation has been described .By multi-well sequence stratigraphy contrast , isochronous stratigraphic framework has been established that has important implications for coalbed methane exploration and mine development work Shibao ore block .%针对川南地区上二叠统龙潭组煤系地层埋深和厚度变化大的特点,以沉积岩石学、层序地层学的理论方法为指导,综合前人研究成果,通过对石宝矿段内上二叠统龙潭组野外露头、钻井岩芯和物探测井资料的研究,识别出区域不整合面、河流冲刷侵蚀面、岩性、岩相转换面和最大海泛面4种层序界面及其物质表现形式,并将其划分为3个长期基准面旋回层序(LSC1-LSC3)和若干中期基准面旋回层序。运用等时对比法,进行连井层序地层对比,建立了等时地层格架。根据基准面旋回升降趋势对各长期旋回层序内物质变化规律和成煤机制进行了系统的描述。认为对石宝矿段的煤层气勘探开发工作具有重要意义。

  15. Summary of the mineralogy of the Colorado Plateau uranium ores

    Science.gov (United States)

    Weeks, Alice D.; Coleman, Robert Griffin; Thompson, Mary E.

    1956-01-01

    In the Colorado Plateau uranium has been produced chiefly from very shallow mines in carnotite ores (oxidized vanadiferous uranium ores) until recent deeper mining penetrated black unoxidized ores in water-saturated rocks and extensive exploration has discovered many deposits of low to nonvanadiferous ores. The uranium ores include a wide range from highly vanadiferous and from as much as one percent to a trace of copper, and contain a small amount of iron and traces of lead, zinc, molybdenum, cobalt, nickel, silver, manganese, and other metals. Recent investigation indicates that the carnotite ores have been derived by progressive oxidation of primary (unoxidized) black ores that contain low-valent uranium and vanadium oxides and silicates. The uranium minerals, uraninite and coffinite, are associated with coalified wood or other carbonaceous material. The vanadium minerals, chiefly montroseite, roscoelite, and other vanadium silicates, occur in the interstices of the sandstone and in siltstone and clay pellets as well as associated with fossil wood. Calcite, dolomite, barite and minor amounts of sulfides, arsenides, and selenides occur in the unoxidized ore. Partially oxidized vanadiferous ore is blue black, purplish brown, or greenish black in contrast to the black or dark gray unoxidized ore. Vanadium combines with uranium to form rauvite. The excess vanadium is present in corvusite, fernandinite, melanovanadite and many other quadrivalent and quinquevalent vanadium minerals as well as in vanadium silicates. Pyrite and part or all of the calcite are replaced by iron oxides and gypsum. In oxidized vanadiferous uranium ores the uranium is fixed in the relatively insoluble minerals carnotite and tyuyamunite, and the excess vanadium commonly combines with one or more of the following: calcium, sodium, potassium, magnesium, aluminum, iron, copper, manganese, or barium, or rarely it forms the hydrated pentoxide. The relatively stable vanadium silicates are little

  16. The Relation between Interstellar Turbulence and Star Formation

    CERN Document Server

    Klessen, R S

    2004-01-01

    (ABBREVIATED) Understanding the formation of stars in galaxies is central to much of modern astrophysics. In this review the relation between interstellar turbulence and star formation is discussed. Supersonic turbulence can provide support against gravitational collapse on global scales, while at the same time it produces localized density enhancements that allow for collapse on small scales. The efficiency and timescale of stellar birth in Galactic gas clouds strongly depend on the properties of the interstellar turbulent velocity field, with slow, inefficient, isolated star formation being a hallmark of turbulent support, and fast, efficient, clustered star formation occurring in its absence. Star formation on scales of galaxies as a whole is expected to be controlled by the balance between gravity andturbulence, just like star formation on scales of individual interstellar gas clouds, but may be modulated by additional effects like cooling and differential rotation. The dominant mechanism for driving inte...

  17. ENVIRONMENTAL ISSUE IN COPPER ORE FLOTATION BY XANTHATES

    National Research Council Canada - National Science Library

    Zoran Markovic

    2015-01-01

      This paper presents some investigation results about potassium ethyl xanthate (PEX) stability in water solution at higher pH and in presence of mineral chalcopyrite, related to flotation of copper minerals from copper ore...

  18. Hunting for Iron Ore Bargains

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    One of China’s leading steel mills has turned to smaller mines for long-term, lowcost iron ore supplies china’s oldest steel producer is looking to South America to fulfill its iron ore needs in the face of rising prices from

  19. Tourmaline as a recorder of ore-forming processes

    Science.gov (United States)

    Slack, J.F.; Trumbull, R.B.

    2011-01-01

    Tourmaline occurs in diverse types of hydrothermal mineral deposits and can be used to constrain the nature and evolution of ore-forming fl uids. Because of its broad range in composition and retention of chemical and isotopic signatures, tourmaline may be the only robust recorder of original mineralizing processes in some deposits. Microtextures and in situ analysis of compositional and isotopic variations in ore-related tourmaline provide valuable insights into hydrothermal systems in seafl oor, sedimentary, magmatic, and metamorphic environments. Deciphering the hydrothermal record in tourmaline also holds promise for aiding exploration programs in the search for new ore deposits.

  20. Combined use of the leucoxene ores of the Yarega deposit with the formation of synthetic rutile and wollastonite and the recovery of rare and rare-earth elements

    Science.gov (United States)

    Sadykhov, G. B.; Zablotskaya, Yu. V.; Anisonyan, K. G.; Olyunina, T. V.

    2016-11-01

    A new process of catalytic autoclave desiliconization of the leucoxene concentrate by lime milk with the formation of synthetic rutile and wollastonite is developed. The general laws of the processes occurring under the conditions of pressure leaching of the concentrate are revealed, and the main leaching parameters that ensure selective desiliconization of leucoxene grains are determined. The leucoxene concentrate is shown to contain rare and rare-earth elements. They are concentrated in synthetic rutile during desiliconization, which facilitates their extraction during subsequent chlorination of rutile.

  1. Contrasting hydrological processes of meteoric water incursion during magmatic-hydrothermal ore deposition: An oxygen isotope study by ion microprobe

    Science.gov (United States)

    Fekete, Szandra; Weis, Philipp; Driesner, Thomas; Bouvier, Anne-Sophie; Baumgartner, Lukas; Heinrich, Christoph A.

    2016-10-01

    Meteoric water convection has long been recognized as an efficient means to cool magmatic intrusions in the Earth's upper crust. This interplay between magmatic and hydrothermal activity thus exerts a primary control on the structure and evolution of volcanic, geothermal and ore-forming systems. Incursion of meteoric water into magmatic-hydrothermal systems has been linked to tin ore deposition in granitic plutons. In contrast, evidence from porphyry copper ore deposits suggests that crystallizing subvolcanic magma bodies are only affected by meteoric water incursion in peripheral zones and during late post-ore stages. We apply high-resolution secondary ion mass spectrometry (SIMS) to analyze oxygen isotope ratios of individual growth zones in vein quartz crystals, imaged by cathodo-luminescence microscopy (SEM-CL). Existing microthermometric information from fluid inclusions enables calculation of the oxygen isotope composition of the fluid from which the quartz precipitated, constraining the relative timing of meteoric water input into these two different settings. Our results confirm that incursion of meteoric water directly contributes to cooling of shallow granitic plutons and plays a key role in concurrent tin mineralization. By contrast, data from two porphyry copper deposits suggest that downward circulating meteoric water is counteracted by up-flowing hot magmatic fluids. Our data show that porphyry copper ore deposition occurs close to a magmatic-meteoric water interface, rather than in a purely magmatic fluid plume, confirming recent hydrological modeling. On a larger scale, the expulsion of magmatic fluids against the meteoric water interface can shield plutons from rapid convective cooling, which may aid the build-up of large magma chambers required for porphyry copper ore formation.

  2. Silicophosphate Sorbents, Based on Ore-Processing Plants' Waste in Kazakhstan

    Science.gov (United States)

    Kubekova, Sholpan N.; Kapralova, Viktoria I.; Telkov, Shamil A.

    2016-01-01

    The problem of ore-processing plants' waste and man-made mineral formations (MMF) disposal is very important for the Republic of Kazakhstan. The research of various ore types (gold, polymetallic, iron-bearing) MMF from a number of Kazakhstan's deposits using a complex physical and chemical methods showed, that the waste's main components are…

  3. Ore-forming mechanism for the Xiaoxinancha Au-rich Cu deposit in Yanbian,Jilin Province,China:Evidence from noble gas isotope geochemistry of fluid inclusions in minerals

    Institute of Scientific and Technical Information of China (English)

    KEISUKE; Nagao; HIROCHIKA; Sumino

    2008-01-01

    The Xiaoxinancha Au-rich copper deposit is one of important Au-Cu deposits along the continental margin in Eastern China. The deposit consists of two sections: the Beishan mine (North), composed of altered rocks with veinlet-dissemination sulfides and melnicovite-dominated sulfide-quartz veins, and the Nanshan mine (South), composed of pyrrhotite-dominated sulfide-quartz veins and pure sulfide veins. The isotope compositions of noble gases extracted from fluid inclusions in ore minerals, i.e. ratios of 3He/4He, 20Ne/22Ne and40Ar/36Ar are in the ranges of 4.45―0.08 Ra, 10.2―8.8 and 306―430, respectively. Fluid inclusions in minerals from the Nanshan mine have higher 3He/4He and 20Ne/22Ne ratios whereas those from the Beishan mine have lower 3He/4He ratios. The analysis of origin, and evolution of the ore fluids and its relations with the ore-forming stages and the ages of mineralization suggests that the initial hydrothermal fluids probably come from the melts generated by partial melting of oceanic crust with the participation of fluids from the mantle (mantle-plume type)/aesthenosphere. This also corresponds to the continental margin settings during the subduction of Izanagi ocaneic plate towards the palaeo-Asian continent (123―102 Ma). The veinlet-dissemination ore bodies of the Beishan mine were formed through replacement and crystallization of the mixed fluids generated by mixing of the ascending high-temperature boiling fluid with young crustal fluid whereas the melnicovite-dominated sulfide-quartz veins were formed subsequently by filling of the high-temperature ore fluid in fissures. Pyrrhotite-dominated sulfide-quartz veins in the Nanshan mine were formed by filling-deposition-crystallization of the moderate-temperature ore fluids and the pure sulfide veins were formed later by filling-deposition-crystallization of ore substance-rich fluids after boiling of the moderate-temperature ore fluids. The metallogenic dynamic processes can be summarized as

  4. Study on relative orbital configuration in satellite formation flying

    Institute of Scientific and Technical Information of China (English)

    Junfeng Li; Xin Meng; Yunfeng Gao; Xiang Li

    2005-01-01

    In this paper, the relative orbital configurations of satellites in formation flying with non-perturbation and J2 perturbation are studied, and an orbital elements method is proposed to obtain the relative orbital configurations of satellites in formation. Firstly, under the condition of nonperturbation, we obtain many shapes of relative orbital configurations when the semi-major axes of satellites are equal.These shapes can be lines, ellipses or distorted closed curves.Secondly, on the basis of the analysis of J2 effect on relative orbital configurations, we find out that J2 effect can induce two kinds of changes of relative orbital configurations. They are distortion and drifting, respectively. In addition, when J2perturbation is concerned, we also find that the semi-major axes of the leading and following satellites should not be the same exactly in order to decrease the J2 effect. The relationship of relative orbital elements and J2 effect is obtained through simulations. Finally, the minimum relation perturbation conditions are established in order to reduce the influence of the J2 effect. The results show that the minimum relation perturbation conditions can reduce the J2 effect significantly when the orbital element differences are small enough, and they can become rules for the design of satellite formation flying.

  5. Elliptical formation control based on relative orbit elements

    Institute of Scientific and Technical Information of China (English)

    Yin Jianfeng; Han Chao

    2013-01-01

    A new set of relative orbit elements (ROEs) is used to derive a new elliptical formation flying model. In-plane and out-of-plane motions can be completely decoupled, which benefits ellip-tical formation design. The inverse transformation of the state transition matrix is derived to study the relative orbit control strategy. Impulsive feedback control laws are developed for both in-plane and out-of-plane relative motions. Control of in-plane and out-of-plane relative motions can be completely decoupled using the ROE-based feedback control law. A tangential impulsive control method is proposed to study the relationship of fuel consumption and maneuvering positions. An optimal analytical along-track impulsive control strategy is then derived. Different typical orbit maneuvers, including formation establishment, reconfiguration, long-distance maneuvers, and for-mation keeping, are taken as examples to demonstrate the performance of the proposed control laws. The effects of relative measurement errors are also considered to validate the high accuracy of the proposed control method.

  6. Microbial reduction of iron ore

    Science.gov (United States)

    Hoffmann, Michael R.; Arnold, Robert G.; Stephanopoulos, Gregory

    1989-01-01

    A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry.

  7. Factors Related to Union Formation among Single Mothers in Canada.

    Science.gov (United States)

    Le Bourdais, Ciline; And Others

    1995-01-01

    Using data on 1,257 women from a 1984 survey, attempts to identify factors associated with union formation among single mothers in Canada. Found that the age of mothers at the beginning of their first episode of single parenthood appears closely related to their chances of forming a union. Other results are discussed. (RJM)

  8. Extrinsic Mechanisms Involved in Age-Related Defective Bone Formation

    DEFF Research Database (Denmark)

    Trinquier, Anne Marie-Pierre Emilie; Kassem, Moustapha

    2011-01-01

    the mechanisms involved in the age-related defective bone formation. Evidence Acquisition: The mechanisms discussed in this review are based on a PubMed search and knowledge of the authors in the field. Evidence Synthesis: Available basic and clinical studies indicate that multiple mechanisms are involved...

  9. Thermochemical analysis of laterite ore alkali roasting: Comparison of sodium carbonate, sodium sulfate, and sodium hydroxide

    Science.gov (United States)

    Samadhi, Tjokorde Walmiki

    2017-01-01

    The abundance of global nickel reserve is in fact dominated by low grade laterite ores containing only approximately 1.0-1.8 %-Ni. Indonesia is a major limonite and saprolite ores source, particularly in the Sulawesi, northern Maluku, and Papua islands. Production of nickel from laterites typically requires a pre-concentration step which breaks down the mineral crystalline structure, thereby facilitating the subsequent extraction of the valuable metals. This work discusses the thermochemical analysis of the alkali roasting of an Indonesian saprolite ore using Na2CO3, Na2SO4, and NaOH. These alkali compounds are selected due to their relatively low cost. The Factsage thermochemical computation package is used to predict thermodynamically stable gaseous, solution, pure liquid, and pure solid phases present in the roasting process at temperatures from 100 to 1200°C at ambient pressure, in inert atmosphere. The formation of a liquid solution (or slag) phase is interpreted as a major indicator of mineral structure breakdown. The computed slag formation temperatures are 373.2, 1041.4, and 792.0°C when using Na2CO3, Na2SO4, and NaOH, respectively. The masses of volatilized alkali at 1200°C with a total feed mass of 100 gram are 0.49, 3.24, and 3.25 mg for Na2CO3, Na2SO4, and NaOH, respectively. It is therefore hypothesized that Na2CO3 is the most competitive sodium-based alkali for saprolite ore roasting.

  10. Experimental measurement of the solubility of bismuth phases in water vapor from 220 deg. C to 300 deg. C: Implications for ore formation

    Energy Technology Data Exchange (ETDEWEB)

    Kruszewski, Jason M. [Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022 (United States); Wood, Scott A., E-mail: swood@uidaho.edu [Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022 (United States)

    2009-04-15

    -vapor and vapor-only experiments further suggests that, at the conditions studied, the solubility of Bi in the vapor is significantly higher than that in the liquid phase (calculated distribution coefficients, i.e., C{sub Vapor}/C{sub Liquid} at 220 deg. C ranged from 81 to 168, where C is concentration in mg/L). The concentrations measured in the vapor-only experiments at 220 deg. C are approximately 11 orders of magnitude higher than those calculated from available thermodynamic data assuming no interaction between volatile Bi species and water molecules. This finding indicates that hydration of volatile Bi species probably occurs to a significant extent; similar to behavior observed previously in published vapor phase solubility studies of other metals. However, the interpretation of the results was complicated by the formation of Bi silicate phases and the lack of certainty that O{sub 2} fugacity buffering was effective throughout the experiments.

  11. Petrological and geochemical features of the early Paleozoic granitic gneisses and iron ores in the Tianhu iron deposit, Eastern Tianshan, NW China: Implications for ore genesis

    Science.gov (United States)

    Zheng, Jiahao; Mao, Jingwen; Yang, Fuquan; Chai, Fengmei; Shen, Ping

    2017-08-01

    This paper reports whole-rock geochemical, zircon U-Pb and Hf isotopic data for ore-hosted granitic gneisses, mineral compositions of oxides, and sulfur isotopic data for sulfides in iron ores from the Tianhu deposit, central part of the Eastern Tianshan. Our results can provide crucial constraints on the genesis of granitic gneisses and early Paleozoic tectonic setting of the Eastern Tianshan. LA-ICP-MS U-Pb dating on magmatic zircons yielded weighted mean 206Pb/238U ages of 463 to 438 Ma, interpreted as the crystallization ages of the granitic protoliths and the formation ages of the Tianhu Group. Zircon U-Pb age of ore-hosted granitic gneiss (ca. 459 Ma) can provide reliable constrains on upper limit for iron mineralization age in the Tianhu deposit. Geochemical characteristics suggest that the protoliths of the Tianhu granitic gneisses are metaluminous to weakly peraluminous high-K calc-alkaline granitic rocks, exhibiting typical subduction-related features such as strong enrichment in LREE and LILE and depletion in HFSE. Zircon Hf isotopic compositions show a positive trend from 463 to 438 Ma, indicating that 460 Ma magmas came from both ancient and juvenile sources, whereas 438 Ma magmas involved more juvenile material. Some early Paleozoic granitoids were recently identified in the Eastern Tianshan with the ages between ca. 475 and ca. 425 Ma. The formation of these early Paleozoic granitoids was in response to subduction processes, suggesting that subduction of Junggar Ocean probably began in the Early Ordovician and lasted until Late Silurian. Pyrite and pyrrhotite in iron ores have δ34SCDT values from + 4.6 to + 15.7‰, which are consistent with the marine source, but inconsistent with the magmatic source or those involved evaporites in skarn iron deposit. Geological, geochemical, and isotopic data suggest that the Tianhu iron ores were formed by volcano-sedimentary processes in a subduction environment during the early Paleozoic time, and Tianhu is a

  12. New isotopic evidence bearing on bonanza (Au-Ag) epithermal ore-forming processes

    Science.gov (United States)

    Saunders, James A.; Mathur, Ryan; Kamenov, George D.; Shimizu, Toru; Brueseke, Matthew E.

    2016-01-01

    New Cu, S, and Pb isotope data provide evidence for a magmatic source of metal(loid)s and sulfur in epithermal Au-Ag deposits even though their ore-forming solutions are composed primarily of heated meteoric (ground) waters. The apparent isotopic discrepancy between ore metals and ore-forming solutions, and even between the ore and associated gangue minerals, indicates two different sources of epithermal ore-forming constituents: (1) a shallow geothermal system that not only provides the bulk of water for the ore-forming solutions but also major chemical constituents leached from host rocks (silica, aluminum, potassium, sodium, calcium) to make gangue minerals and (2) metals and metalloids (As, Te, Sb, etc.) and sulfur (±Se) derived from deeper magma bodies. Isotopic data are consistent with either vapor-phase transport of metal(loids) and sulfur and their subsequent absorption by shallow geothermal waters or formation of metallic (Au, Ag, Cu phases) nanoparticles at depth from magmatic fluids prior to encountering the geothermal system. The latter is most consistent with ore textures that indicate physical transport and aggregation of nanoparticles were significant ore-forming processes. The recognition that epithermal Au-Ag ores form in tectonic settings that produce magmas capable of releasing metal-rich fluids necessary to form these deposits can refine exploration strategies that previously often have focused on locating fossil geothermal systems.

  13. Determination of tellurium in ores, concentrates and related materials by graphite-furnace atomic-absorption spectrometry after separations by iron collection and xanthate extraction.

    Science.gov (United States)

    Donaldson, E M; Leaver, M E

    1990-02-01

    A method for determining approximately 0.01 mug/g or more of tellurium in ores, concentrates, rocks, soils and sediments is described. After sample decomposition and evaporation of the solution to incipient dryness, tellurium is separated from > 300 mug of copper by co-precipitation with hydrous ferric oxide from an ammoniacal medium and the precipitate is dissolved in 10M hydrochloric acid. Alternatively, for samples containing 300 mug of copper, the salts are dissolved in 10M hydrochloric acid. Tellurium in the resultant solutions is reduced to the quadrivalent state by heating and separated from iron, lead and various other elements by a single cyclohexane extraction of its xanthate complex from approximately 9.5M hydrochloric acid in the presence of thiosemicarbazide as a complexing agent for copper. After washing with 10M hydrochloric acid followed by water to remove residual iron, chloride and soluble salts, tellurium is stripped from the extract with 16M nitric acid and finally determined, in a 2% v/v nitric acid medium, by graphite-furnace atomic-absorption spectrometry at 214.3 nm in the presence of nickel as matrix modifier. Small amounts of gold and palladium, which are partly co-extracted as xanthates if the iron-collection step is omitted, do not interfere. Co-extraction of arsenic is avoided by volatilizing it as the bromide during the decomposition step. The method is directly applicable, without the co-precipitation step, to most rocks, soils and sediments.

  14. Determination of chromium in ores, rocks and related materials, iron, steel and non-ferrous alloys by atomic-absorption spectrophotometry after separation by tribenzylamine-chloroform extraction.

    Science.gov (United States)

    Donaldson, E M

    1980-10-01

    A method for determining trace and moderate amounts of chromium in ores, concentrates, rocks, soils and clays is described. After fusion of the sample with sodium peroxide, the melt is dissolved in dilute sulphuric acid. The chromium(III) produced by the hydrogen peroxide formed is co-precipitated with hydrous ferric oxide. The precipitate is dissolved in 0.7M sulphuric acid and chromium oxidized to chromium(VI) with ceric ammonium sulphate. The chromium(VI) is extracted as an ion-association complex into chloroform containing tribenzylamine and stripped with ammoniacal hydrogen peroxide. This solution is acidified with perchloric acid and chromium determined by atomic-absorption spectrophotometry in an air-acetylene flame, at 357.9 nm. Barium and strontium do not interfere. The procedure is also applicable to iron and steel, and nickel-copper, aluminium and zirconium alloys. Up to 5 mg of manganese and 10 mg each of molybdenum and vanadium will not interfere. In the absence of vanadium, up to 10 mg of tungsten will not interfere. In the presence of 1 mg of vanadium, up to 1 mg of tungsten will not interfere.

  15. Nonlinear Effects of Laser Surface Modification of Ore Minerals

    Directory of Open Access Journals (Sweden)

    N.A. Leonenko

    2015-12-01

    Full Text Available The effect of continuous laser radiation on complex ore minerals objects containing gold, not extracted by monerd methods was investigated. It was established the formation of different structural surfaces of gold, revealed general patterns of sintering and concentration of sub-micron gold.

  16. Technogenic hydrogeochemical anomalies of tungsten deposits in Kykylbey ore region

    Institute of Scientific and Technical Information of China (English)

    Leonid V.Zamana; Larisa P.Chechel

    2004-01-01

    Peculiarities of the tungsten deposits drainage flow chemical composition formation, the development of which was ceased almost 40 years ago, have been considered. Migration peculiarities of ore components have been covered, and forms of their migration have been calculated. Inertial characteristics of the surface flow contamination are shown.

  17. The study of ore minerals parageneses in Ponorogo area, East Java

    Directory of Open Access Journals (Sweden)

    Wiwik Dyah Hastuti Endang

    2017-01-01

    Full Text Available The present study was undertaken in the Southern Mountain Range of East Jawa, Ponorogo District. Tectonically, the region extends along the Magmatic Sunda-Banda Arc, which comprises predominantly volcanic rocks of Mandalika Formation, sedimentary rock units of Arjosari Formation, and intrusive sequences such as dacite, andesite and diorite. Structurally, the region is controlled by faults striking NE-SW, NW-SE and N-S. Mandalika Formation and Arjosari Formation have an interfingering relation and are Oligo-Miocene. Results of the field observation and analyses of petrography and mineragraphy on outcrops reveal that the region has commonly undergone alteration and mineralisation. The principle ore minerals occurring in the Ponorogo area are pyrite and sphalerite with abundant mineral assemblages of chalcopyrite, magnetite, hematite, galena, covelite, bornite, and limonite. Mineralisation occurs in argillic zone and subprophyllitic zone. Based on textures, structures and ore mineral assemblages, mineralisation in the study area can be devided at least into two stages. The earlier stage was present in relation to hypogene processes, and resulted in pyrite–sphalerite–chalcopyrite–magnetite– galena. The subsequent stage took place due to supergene enrichment processes, and yielded pyrite– sphalerite–covelite–bournite–limonite. Such mineral assemblages suggest that they are formed at temperatures of about 100–360° C.

  18. Ore-bearing hydrothermal metasomatic processes in the Elbrus volcanic center, the northern Caucasus, Russia

    Science.gov (United States)

    Gurbanov, A. G.; Bogatikov, O. A.; Dokuchaev, A. Ya.; Gazeev, V. M.; Abramov, S. S.; Groznova, E. O.; Shevchenko, A. V.

    2008-06-01

    Precaldera, caldera, and postcaldera cycles are recognized in the geological evolution of the Pleistocene-Holocene Elbrus volcanic center (EVC). During the caldera cycle, the magmatic activity was not intense, whereas hydrothermal metasomatic alteration of rocks was vigorous and extensive. The Kyukyurtli and Irik ore-magmatic systems have been revealed in the EVC, with the former being regarded as the more promising one. The ore mineralization in rocks of the caldera cycle comprises occurrences of magnetite, ilmenite, pyrite and pyrrhotite (including Ni-Co varieties), arsenopyrite, chalcopyrite, millerite, galena, and finely dispersed particles of native copper. Pyrite and pyrrhotite from volcanics of the caldera cycle and dacite of the Kyukyurtli extrusion are similar in composition and differ from these minerals of the postcaldera cycle, where pyrite and pyrrhotite are often enriched in Cu, Co, and Ni and millerite is noted as well. The composition of ore minerals indicates that the hydrothermal metasomatic alteration related to the evolution of the Kyukyurtli hydrothermal system was superimposed on rocks of the caldera cycle, whereas the late mineralization in rocks of the postcaldera cycle developed autonomously. The homogenization temperature of fluid inclusions in quartz and carbonate from crosscutting veinlets in the apical portion of the Kyukyurtli extrusion is 140-170°C and in quartz from geyserite, 120-150°C. The temperature of formation of the chalcopyrite-pyrite-pyrrhotite assemblage calculated using mineral geothermometers is 156 and 275°C in dacite from the middle and lower portions of the Malka lava flow and 190°C in dacite of the Kyukyurtli extrusion. The hydrothermal solutions that participated in metasomatic alteration of rocks pertaining to the Kyukyurtli ore-magmatic system (KOMS) and formed both secondary quartzite and geyserite were enriched in fluorine, as evidenced from the occurrence of F-bearing minerals-zharchikhite, ralstonite,

  19. Characteristics and origin of ore-forming fluids of Jinchangqing gold (copper) ore deposit (s) in Xiangyun, Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    HE Mingqin; SONG Huanbin; LIU Jiajun; LI Chaoyang

    2005-01-01

    On the basis of results of the studies of primary fluid inclusions, and the hydrogen and oxygen isotope data, the authors concluded that the early-stage ore-forming fluid from the Jinchangqing gold (copper) ore deposit is a kind of sulfate type hot brine characterized by medium temperature and salinity, genetically related to the late-stage ore-forming fluid derived from an acidic and more reductive environment. However, the late-stage ore-forming fluid is a sort of low temperature and low salinity chloride-type hot brine which originated from a lower pressure, acidic and more oxidative environment. In general, the ore fluids were derived from the late-stage, or largely from the early-stage groundwater-derived meteoric water, which has a 12‰-17‰ heavier oxygen isotopic composition than the original rain water (δ 18 O= -15.3‰ ), and were formed during gold mineralization as a product of oxygen isotope exchange during the reaction between ore-forming fluid and wall rocks under a lower water/rock ratio condition.

  20. Bounded relative orbits about asteroids for formation flying and applications

    Science.gov (United States)

    Baresi, Nicola; Scheeres, Daniel J.; Schaub, Hanspeter

    2016-06-01

    The relative motion about 4179 Toutatis is studied in order to investigate the feasibility of formation flying as an alternative concept for future asteroid exploration missions. In particular, the existence of quasi-frozen orbits about slowly rotating bodies allows us to compute families of periodic orbits in the body-fixed frame of the asteroid. Since these periodic orbits are of the center×center type, quasi-periodic invariant tori are calculated via fully numerical procedures and used to initialize spacecraft formations about the central body. Numerical simulations show that the resulting in-plane and out-of-plane relative trajectories remain bounded over long time spans; i.e., more than 30 days.

  1. Porosity and Velocity Relations of Grosmont Formation, Alberta, Canada

    Science.gov (United States)

    Keehm, Y.; Hu, D.

    2010-12-01

    We present results on porosty-velocity relations of Grosmont formation, Alberta, Canada, which is one of largest bitumen carbonate reservoirs. Grosmont formation is divided into four units: LG; UG-1; UG-2; and UG-3 from the bottom. Two lower units are mainly imestone, while upper units are mostly dolomite with vuggy porosity and fractures, which makes the upper units be a good reservoir. Rock physics modeling was then performed to quantify porosity-velocity relations for the four units, which enables us to predict porosity from seismic data. To incorporate the pore-scale details in the modeling, we used DEM (differential effective medium) models. Two lower units are very similar in velocity-porosity domain, thus the relations can be represented by one velocity-porosity model, which is used as our reference model. For the UG-2 unit, we found that one model cannot represent the unit since the degree of fracturing are heterogeneous from location to location. We thus suggested three different DEM models for the UG-2 unit: vuggy-dominant; mildly-fractured; and heavily-fractured. The UG-3 units can be modeled with vuggy porosity, and fractures were not very noticeable. We also investigated the spatial variation of the UG-2 unit, and found that the degree of fracturing is generally proportional to the proximity to the unconformity boundary, where the fresh water invasion can be dominant. In conclusion, we proposed velocity-porosity relations for the four units in Grosmont formation, and believe that these models can help to characterize the reservoir quality. In addition, since the proximity of reservoir to the unconformity boundary highly affects the degree of fracturing, a careful analysis of spatial variation would be essential for the successful characterization of Grosmont formation. Acknowledgement: This work was supported by the Energy R&D program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government

  2. A cautionary note about composite Galactic star formation relations

    CERN Document Server

    Parmentier, Genevieve

    2016-01-01

    We explore the pitfalls which affect the comparison of the star-formation (SF) relation for nearby molecular clouds with that for distant compact molecular clumps. We show that both relations behave differently in the ($\\Sigma_{gas}$, $\\Sigma_{SFR}$) space, where $\\Sigma_{gas}$ and $\\Sigma_{SFR}$ are, respectively, the gas and SF rate surface densities, even when the physics of star formation is the same. This is because the SF relation of nearby clouds relates gas and star surface densities measured locally, that is, within a given interval of gas surface density, or at a given protostar location. We refer to such measurements as local measurements, and the corresponding SF relation as the local relation. In contrast, the stellar content of a distant molecular clump remains unresolved. Only the mean SF rate can be obtained from e.g. the clump infrared luminosity. One clump therefore provides one single point to the ($\\Sigma_{gas}$, $\\Sigma_{SFR}$) space, that is, its mean gas surface density and SF rate surf...

  3. The giant Bayan Obo REE-Nb-Fe deposit, China: Controversy and ore genesis

    Directory of Open Access Journals (Sweden)

    Hong-Rui Fan

    2016-05-01

    Full Text Available Bayan Obo ore deposit is the largest rare-earth element (REE resource, and the second largest niobium (Nb resource in the world. Due to the complicated element/mineral compositions and involving several geological events, the REE enrichment mechanism and genesis of this giant deposit still remains intense debated. The deposit is hosted in the massive dolomite, and nearly one hundred carbonatite dykes occur in the vicinity of the deposit. The carbonatite dykes can be divided into three types from early to late: dolomite, co-existing dolomite-calcite and calcite type, corresponding to different evolutionary stages of carbonatite magmatism based on the REE and trace element data. The latter always has higher REE content. The origin of the ore-hosting dolomite at Bayan Obo has been addressed in various models, ranging from a normal sedimentary carbonate rocks to volcano-sedimentary sequence, and a large carbonatitic intrusion. More geochemical evidences show that the coarse-grained dolomite represents a Mesoproterozoic carbonatite pluton and the fine-grained dolomite resulted from the extensive REE mineralization and modification of the coarse-grained variety. The ore bodies, distributed along an E–W striking belt, occur as large lenses and underwent more intense fluoritization and fenitization. The first episode mineralization is characterized by disseminated mineralization in the dolomite. The second or main-episode is banded and/or massive mineralization, cut by the third episode consisting of aegirine-rich veins. Various dating methods gave different mineralization ages at Bayan Obo, resulting in long and hot debates. Compilation of available data suggests that the mineralization is rather variable with two peaks at ∼1400 and 440 Ma. The early mineralization peak closes in time to the intrusion of the carbonatite dykes. A significant thermal event at ca. 440 Ma resulted in the formation of late-stage veins with coarse crystals of REE

  4. Uranium mill ore dust characterization

    Energy Technology Data Exchange (ETDEWEB)

    Knuth, R.H.; George, A.C.

    1980-11-01

    Cascade impactor and general air ore dust measurements were taken in a uranium processing mill in order to characterize the airborne activity, the degree of equilibrium, the particle size distribution and the respirable fraction for the /sup 238/U chain nuclides. The sampling locations were selected to limit the possibility of cross contamination by airborne dusts originating in different process areas of the mill. The reliability of the modified impactor and measurement techniques was ascertained by duplicate sampling. The results reveal no significant deviation from secular equilibrium in both airborne and bulk ore samples for the /sup 234/U and /sup 230/Th nuclides. In total airborne dust measurements, the /sup 226/Ra and /sup 210/Pb nuclides were found to be depleted by 20 and 25%, respectively. Bulk ore samples showed depletions of 10% for the /sup 226/Ra and /sup 210/Pb nuclides. Impactor samples show disequilibrium of /sup 226/Ra as high as +-50% for different size fractions. In these samples the /sup 226/Ra ratio was generally found to increase as particle size decreased. Activity median aerodynamic diameters of the airborne dusts ranged from 5 to 30 ..mu..m with a median diameter of 11 ..mu..m. The maximum respirable fraction for the ore dusts, based on the proposed International Commission on Radiological Protection's (ICRP) definition of pulmonary deposition, was < 15% of the total airborne concentration. Ore dust parameters calculated for impactor duplicate samples were found to be in excellent agreement.

  5. Chemical state mapping of heterogeneous reduction of iron ore sinter

    Science.gov (United States)

    Kimura, M.; Takeichi, Y.; Murao, R.; Obayashi, I.; Hiraoka, Y.; Liu, Y.

    2017-06-01

    Iron ore sinter constitutes the major component of the iron-bearing burden in blast furnaces, and its reduction mechanism is one of the keys to improving the productivity of ironmaking. Iron ore sinter is composed of multiple iron oxide phases and calcium ferrites (CFs), and their heterogeneous reduction was investigated in terms of changes in iron chemical state: FeIII, FeII, and Fe0 were examined macroscopically by 2D X-ray absorption and microscopically by 3D transmission X-ray microscopy (TXM). It was shown that the reduction starts at iron oxide grains rather than at calcium ferrite (CF) grains, especially those located near micropores. The heterogeneous reduction causes crack formation and deteriorates the mechanical strength of the sinter. These results help us to understand the fundamental aspects of heterogeneous reduction schemes in iron ore sinter.

  6. Lead isotope studies of the Guerrero composite terrane, west-central Mexico: implications for ore genesis

    Science.gov (United States)

    Potra, Adriana; Macfarlane, Andrew W.

    2014-01-01

    New thermal ionization mass spectrometry and multi-collector inductively coupled plasma mass spectrometry Pb isotope analyses of three Cenozoic ores from the La Verde porphyry copper deposit located in the Zihuatanejo-Huetamo subterrane of the Guerrero composite terrane are presented and the metal sources are evaluated. Lead isotope ratios of 3 Cenozoic ores from the El Malacate and La Esmeralda porphyry copper deposits located in the Zihuatanejo-Huetamo subterrane and of 14 ores from the Zimapan and La Negra skarn deposits from the adjoining Sierra Madre terrane are also presented to look for systematic differences in the lead isotope trends and ore metal sources among the proposed exotic tectonostratigraphic terranes of southern Mexico. Comparison among the isotopic signatures of ores from the Sierra Madre terrane and distinct subterranes of the Guerrero terrane supports the idea that there is no direct correlation between the distinct suspect terranes of Mexico and the isotopic signatures of the associated Cenozoic ores. Rather, these Pb isotope patterns are interpreted to reflect increasing crustal contribution to mantle-derived magmas as the arc advanced eastward onto a progressively thicker continental crust. The lead isotope trend observed in Cenozoic ores is not recognized in the ores from Mesozoic volcanogenic massive sulfide and sedimentary exhalative deposits. The Mesozoic ores formed prior to the amalgamation of the Guerrero composite terrane to the continental margin, which took place during the Late Cretaceous, in intraoceanic island arc and intracontinental marginal basin settings, while the Tertiary deposits formed after this event in a continental arc setting. Lead isotope ratios of the Mesozoic and Cenozoic ores appear to reflect these differences in tectonic setting of ore formation. Most Pb isotope values of ores from the La Verde deposit (206Pb/204Pb = 18.674-18.719) are less radiogenic than those of the host igneous rocks, but plot within the

  7. Linear and Nonlinear Relative Navigation Strategies for Small Satellite Formation Flying Based on Relative Position Measurement

    Science.gov (United States)

    Zhang, Xiaomin; Zheng, You

    Based on linear and nonlinear mathematical model of spacecraft formation flying and technology of relative position measurement of small satellites, the linear and nonlinear relative navigation strategies are developed in this paper. The dynamical characteristics of multi spacecraft formation flying have been researched in many references, including the authors' several International Astronautical Congress papers with numbers of IAF-98-A.2.06, IAA-99-IAA.11.1.09, IAA-01-IAA.11.4.08. Under conditions of short distance and short time, the linear model can describe relative orbit motion; otherwise, nonlinear model must be adopted. Furthermore the means of measurement and their error will influence relative navigation. Thus three kinds of relative navigation strategy are progressed. With consideration of difficulty in relative velocity measurement of small satellites, the three relative navigation strategies are proposed and only depend on sequential data of relative position through measuring the relative distance and relative orientation. The first kind of relative navigation strategy is based on linear model. The second relative navigation strategy is based on nonlinear model, with inclusion of the second order item. In fact the measurement error can not be avoided especially for small satellites, it is mainly considered in the third relative navigation strategy. This research is theoretical yet and a series of formulas of relative navigation are presented in this paper. Also the authors analyzed the three strategies qualitatively and quantitatively. According to results of simulation, the ranges of application are indicated and suggested in allusion to the three strategies of relative navigation. On the view of authors, the relative navigation strategies for small satellite formation flying based on relative position measurement are significant for engineering of small satellite formation flying.

  8. Physical-chemical conditions of ore deposition

    Science.gov (United States)

    Barton, P.B.

    1981-01-01

    Ore deposits form under a wide range of physical and chemical conditions, but those precipitating from hot, aqueous fluids-i.e. the hydrothermal deposits-form generally below 700??C and at pressures of only 1 or 2 kbar or less. Natural aqueous fluids in rocks may extract metal and sulfur from a variety of rock types or may acquire them as a residual heritage from a crystallizing silicate magma. Ore-forming hydrothermal fluids never appear as hot springs (except in deep, submarine situations) because they boil, mix with surface waters, and cool, thereby losing their ore-bearing ability before reaching the surface. Mineral systems function as chemical buffers and indicators just as buffers and indicators function in a chemical laboratory. By reading the record written in the buffer/indicator assemblages of minerals one can reconstruct many aspects of the former chemical environment. By studying the record of changing conditions one may deduce information regarding the processes functioning to create the succession of chemical environments and the ore deposits they represent. The example of the OH vein at Creede, Colorado, shows a pH buffered by the K-feldspar + muscovite + quartz assemblage and the covariation of S2 and O2 buffered by the assemblage chlorite + pyrite + quartz. Boiling of the ore fluid led to its oxidation to hematite-bearing assemblages and simultaneously produced an intensely altered, sericitic capping over the vein in response to the condensation of vapors bearing acidic components. The solubility of metals as calculated from experimental and theoretical studies of mineral solubility appears too low by at least one or two powers of ten to explain the mineralization at Creede. In contrast to Creede where the mineral stabilities all point to a relatively consistent chemistry, the Mississippi Valley type deposits present a puzzle of conflicting chemical clues that are impossible to reconcile with any single equilibrium situation. Thus we must

  9. Physical-chemical conditions of ore deposition

    Science.gov (United States)

    Barton, Paul B.

    Ore deposits form under a wide range of physical and chemical conditions, but those precipitating from hot, aqueous fluids-i.e. the hydrothermal deposits-form generally below 700°C and at pressures of only 1 or 2 kbar or less. Natural aqueous fluids in rocks may extract metal and sulfur from a variety of rock types or may acquire them as a residual heritage from a crystallizing silicate magma. Ore-forming hydrothermal fluids never appear as hot springs (except in deep, submarine situations) because they boil, mix with surface waters, and cool, thereby losing their ore-bearing ability before reaching the surface. Mineral systems function as chemical buffers and indicators just as buffers and indicators function in a chemical laboratory. By reading the record written in the buffer/indicator assemblages of minerals one can reconstruct many aspects of the former chemical environment. By studying the record of changing conditions one may deduce information regarding the processes functioning to create the succession of chemical environments and the ore deposits they represent. The example of the OH vein at Creede, Colorado, shows a pH buffered by the K-feldspar + muscovite + quartz assemblage and the covariation of S 2 and O 2 buffered by the assemblage chlorite + pyrite + quartz. Boiling of the ore fluid led to its oxidation to hematite-bearing assemblages and simultaneously produced an intensely altered, sericitic capping over the vein in response to the condensation of vapors bearing acidic components. The solubility of metals as calculated from experimental and theoretical studies of mineral solubility appears too low by at least one or two powers of ten to explain the mineralization at Creede. In contrast to Creede where the mineral stabilities all point to a relatively consistent chemistry, the Mississippi Valley type deposits present a puzzle of conflicting chemical clues that are impossible to reconcile with any single equilibrium situation. Thus we must

  10. The north-subducting Rheic Ocean during the Devonian: consequences for the Rhenohercynian ore sites

    Science.gov (United States)

    von Raumer, Jürgen F.; Nesbor, Heinz-Dieter; Stampfli, Gérard M.

    2016-11-01

    Base metal mining in the Rhenohercynian Zone has a long history. Middle-Upper Devonian to Lower Carboniferous sediment-hosted massive sulfide deposits (SHMS), volcanic-hosted massive sulfide deposits (VHMS) and Lahn-Dill-type iron, and base metal ores occur at several sites in the Rhenohercynian Zone that stretches from the South Portuguese Zone, through the Lizard area, the Rhenish Massif and the Harz Mountain to the Moravo-Silesian Zone of SW Bohemia. During Devonian to Early Carboniferous times, the Rhenohercynian Zone is seen as an evolving rift system developed on subsiding shelf areas of the Old Red continent. A reappraisal of the geotectonic setting of these ore deposits is proposed. The Middle-Upper Devonian to Early Carboniferous time period was characterized by detrital sedimentation, continental intraplate and subduction-related volcanism. The large shelf of the Devonian Old Red continent was the place of thermal subsidence with contemporaneous mobilization of rising thermal fluids along activated Early Devonian growth faults. Hydrothermal brines equilibrated with the basement and overlying Middle-Upper Devonian detrital deposits forming the SHMS deposits in the southern part of the Pyrite Belt, in the Rhenish Massif and in the Harz areas. Volcanic-hosted massive sulfide deposits (VHMS) formed in the more eastern localities of the Rhenohercynian domain. In contrast, since the Tournaisian period of ore formation, dominant pull-apart triggered magmatic emplacement of acidic rocks, and their metasomatic replacement in the apical zones of felsic domes and sediments in the northern part of the Iberian Pyrite belt, thus changing the general conditions of ore precipitation. This two-step evolution is thought to be controlled by syn- to post-tectonic phases in the Variscan framework, specifically by the transition of geotectonic setting dominated by crustal extension to a one characterized by the subduction of the supposed northern slab of the Rheic Ocean

  11. Study on the multi-sources of ore-forming materials and ore-forming fluids in the Huize lead-zinc ore deposit

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhenliang; HUANG Zhilong; GUAN Tao; YAN Zaifei; GAO Derong

    2005-01-01

    The Huize large-sized Pb-Zn deposit in Yunnan Province, China, is characterized by favorable metallogenic background and particular geological settings. This suggested that the ore-forming mechanism is relatively unique. On the basis of geological features such as the contents of mineralization elements, the REE concentrations of gangue calcites, the REE concentrations of calcite veins in the NE-trending tectonic zone and the Pb, Sr, C, H and O isotopic compositions of different minerals, this paper presents that the ore-forming materials and ore-forming fluids of the deposit were derived from various types of strata or rocks. This is a very significant conclusion for us to further discuss the mineralization mechanism of the deposit at depth and establish an available genetic model.

  12. ORIGIN OF THE GALAXY MASS-METALLICITY-STAR FORMATION RELATION

    Energy Technology Data Exchange (ETDEWEB)

    Harwit, Martin; Brisbin, Drew, E-mail: harwit@verizon.net [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States)

    2015-02-20

    We describe an equilibrium model that links the metallicity of low-redshift galaxies to stellar evolution models. It enables the testing of different stellar initial mass functions and metal yields against observed galaxy metallicities. We show that the metallicities of more than 80,000 Sloan Digital Sky Survey galaxies in the low-redshift range 0.07 ≤ z ≤ 0.3 considerably constrain stellar evolution models that simultaneously relate galaxy stellar mass, metallicity, and star formation rates to the infall rate of low-metallicity extragalactic gas and outflow of enriched matter. A feature of our model is that it encompasses both the active star forming phases of a galaxy and epochs during which the same galaxy may lie fallow. We show that the galaxy mass-metallicity-star formation relation can be traced to infall of extragalactic gas mixing with native gas from host galaxies to form stars of observed metallicities, the most massive of which eject oxygen into extragalactic space. Most consequential among our findings is that, on average, extragalactic infall accounts for one half of the gas required for star formation, a ratio that is remarkably constant across galaxies with stellar masses ranging at least from M* = 2 × 10{sup 9} to 6 × 10{sup 10} M {sub ☉}. This leads us to propose that star formation is initiated when extragalactic infall roughly doubles the mass of marginally stable interstellar clouds. The processes described may also account quantitatively for the metallicity of extragalactic space, though to check this the fraction of extragalactic baryons will need to be more firmly established.

  13. Concentration Mechanism of Ore-Forming Fluid in Huize Lead-Zinc Deposits, Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhenliang; Huang Zhilong; Rao Bing; Guan Tao; Yan Zaifei

    2005-01-01

    The Huize Pb-Zn deposits of Yunnan Province, located in the south-central part of the Sichuan-Yunnan-Guizhou (SYG) Pb-Zn multimetal mineralization district (MMD), are strictly controlled by fault zones. The sources of ore-forming fluid in the deposits have been debated for a long time. Calcite, a gangue mineral, has uniform C and O isotopes. The δ13CPDB and δ18OSMOW values vary respectively from -2.1×10-3 to -3.5×10-3 (mean -2.8×10-3) and 16.7×10-3-18.6×10-3 (mean 17.7×10-3). No obvious difference can be found in C and O isotopes among occurrences and elevations and even ore-bodies. Types of inclusions include those of pure liquid (L), liquid-rich gas-liquid (L+V), and three-phase ones containing a daughter mineral (S+L+V) and immiscible CO2 with three-phases (VCO2+LCO2+LH2O). Their homogenization temperatures vary from 110 to 400 ℃, and two peaks are shown. (87Sr/86Sr)0 ratios of calcite in the deposits are higher than those in the mantle and Emeishan basalts, and slightly higher than those in the Baizuo Formation, which the Huize lead-zinc deposits are found in. All of the (87Sr/86Sr)0 are low relative to those in the basement rocks. Fractionation of Sr isotope did not occur in the ore-forming fluid during the precipitation of minerals. The results indicate that the ore-forming fluid is homogeneous and derived from the mixing of different fluids. Gas-liquid inclusions can be separated into two groups in 300-400 ℃ with a salinity of 5 %-6 % and 12 %-16 % NaCl respectively. However, the salinities of inclusions vary from 7 % to 23 % NaCl in 100-300 ℃, especially in 150-250 ℃. The formation pressures of faulted zones are (50-320)×105 Pa. The estimated pressures of the overlying rocks on the ore bodies are 574×105-640×105 Pa. The pressures of ore-forming processes would be 145×105 to 754×105 Pa. Therefore, pressure sharply reduced and boiling occurred when the ore-forming fluid flew into the fault zones. As a result, the ore-forming fluid was

  14. Mineral types of hydrothermal alteration zones in the Dukat ore field and their relationships to leucogranite and epithermal gold-silver ore, northeastern Russia

    Science.gov (United States)

    Filimonova, L. G.; Trubkin, N. V.; Chugaev, A. V.

    2014-05-01

    The paper considers the localization of potassic and propylitic hydrothermal alteration zones in the domal volcanic-plutonic structure controlling the position of the Dukat ore field with the eponymous unique epithermal Au-Ag deposit. Comprehensive mineralogical and geochemical data on rocks and minerals in hydrothermal alteration zones and associated intrusions have shown that quartz-jarosite-sericite, quartz-pyrite-sericite, and quartz-adularia-chlorite alterations were formed with the participation of fluid flows related to a fingerlike projection of a high-K leucogranite porphyry intrusion with large phenocrysts. These hydrothermal alterations developed in the rifted graben under conditions of divergent plate boundaries, whereas quartz-clinozoisite-calcite, epidote-chlorite, and garnet-calcite-chlorite alterations were linked to K-Na leucogranite intrusive bodies and developed under conditions of convergent plate boundaries reactivated as a result of formation of the marginal Okhotsk-Chukotka volcanic belt. Phase separation and coagulation of specific portions of ascending fluids resulted in the formation and stabilization of small-sized particles of native silver and other ore components, which enabled involvement in flows of secondary geothermal solutions and ore-forming fluids. The Sr, Nd, and Pb isotopic compositions of rocks and minerals from the hydrothermal alteration zones, associated intrusions, and economic orebodies at the Dukat deposit indicate that their components have been derived from the juvenile continental crust, which was altered in pre-Cretaceous periods of endogenic activity. The components of gangue minerals of potassic and propylitic hydrothertmal alterations and associated intrusions have been taken from deep sources differing in 87Sr/86Sr and 143Nd/144Nd at similar U/Pb and Th/Pb ratios. Chalcophile lead in products of hydrothermal activity and melanocratic inclusions in leucogranite has been taken from regions with elevated U/Pb and

  15. Genetic characteristics of fluid inclusions in sphalerite from the Silesian-Cracow ores, Poland

    Science.gov (United States)

    Kozlowski, A.; Leach, D.L.; Viets, J.G.

    1996-01-01

    Fluid inclusion studies in sphalerite from early-stage Zn-Pb mineralization in the Silesian-Cracow region (southern Poland), yielded homogenization temperatures (Th) from 80 to 158??C. Vertical thermal gradient of the parent fluids was 6 to 10??C, and the ore crystallization temperature ranges varied from recrystallization of ores, and Th distribution in single fissure fillings were considered. The ore-forming fluids were liquid-hydrocarbon-bearing aqueous solutions of Na-Ca-Cl type with lower Ca contents in the south and higher Ca contents in the north of the region. The ore-forming fluids had salinities from nul to about 23 weight percent of NaCl equivalent. Three types of fluids were recognized, that mixed during ore precipitation: a) ascending fluids of low-to-moderate salinity and high, b) formation brines of high salinity and moderate Th, and c) descending waters of low salinity and low-to-moderate Th.

  16. Fluorosilicone and silicone o-ring aging study.

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Robert; Gillen, Kenneth T.

    2007-10-01

    Fluorosilicone o-ring aging studies were performed. These studies examined the compressive force loss of fluorosilicone o-rings at accelerated (elevated) temperatures and were then used to make predictions about force loss at room temperature. The results were non-Arrhenius with evidence for a lowering in Arrhenius activation energies as the aging temperature was reduced. The compression set of these fluorosilicone o-rings was found to have a reasonably linear correlation with the force loss. The aging predictions based on using the observed curvature of the Arrhenius aging plots were validated by field aged o-rings that yielded degradation values reasonably close to the predictions. Compression set studies of silicone o-rings from a previous study resulted in good correlation to the force loss predictions for the fluorosilicone o-rings from this study. This resulted in a preliminary conclusion that an approximately linear correlation exists between compression set and force decay values for typical fluorosilicone and silicone materials, and that the two materials age at similar rates at low temperatures. Interestingly, because of the observed curvature of the Arrhenius plots available from longer-term, lower temperature accelerated exposures, both materials had faster force decay curves (and correspondingly faster buildup of compression set) at room temperature than anticipated from typical high-temperature exposures. A brief study on heavily filled conducting silicone o-rings resulted in data that deviated from the linear relationship, implying that a degree of caution must be exercised about any general statement relating force decay and compression set.

  17. The Relation Between Halo Shape, Velocity Dispersion and Formation Time

    CERN Document Server

    Ragone-Figueroa, C; Merchan, M; Gottlober, S; Yepes, G

    2010-01-01

    We use dark matter haloes identified in the MareNostrum Universe and galaxy groups identified in the Sloan Data Release 7 galaxy catalogue, to study the relation between halo shape and halo dynamics, parametrizing out the mass of the systems. A strong shape-dynamics, independent of mass, correlation is present in the simulation data, which we find it to be due to different halo formation times. Early formation time haloes are, at the present epoch, more spherical and have higher velocity dispersions than late forming-time haloes. The halo shape-dynamics correlation, albeit weaker, survives the projection in 2D (ie., among projected shape and 1-D velocity dispersion). A similar shape-dynamics correlation, independent of mass, is also found in the SDSS DR7 groups of galaxies and in order to investigate its cause we have tested and used, as a proxy of the group formation time, a concentration parameter. We have found, as in the case of the simulated haloes, that less concentrated groups, corresponding to late fo...

  18. Numerical Modelling of Ore-forming Dynamics of Fractal Dispersive Fluid Systems

    Institute of Scientific and Technical Information of China (English)

    邓军; 方云; 杨立强; 杨军臣; 孙忠实; 王建平; 丁式江; 王庆飞

    2001-01-01

    Based on an analysis of the fractal structures and mass transport mechanism of typical shear-fluid-ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore formation system. The model of point-source diffusive illuviation of the shear-fluid-ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore-forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore-forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore-forming dynamics is a combination of multi-processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and fluid-rock interaction. It changes components and physico-chemical properties of primary rocks and fluids, favouring deposition and mineralization of ore-forming materials. (3) Gold ore-forming processes in different types of shear zones are quite different. (1) In a metallogenic system with inhomogeneous volumetric change and inhomogeneous shear, mineralization occurs in structural barriers in the centre of a shear zone and in geochemical barriers in the shear zone near its boundaries. But there is little possibility of mineralization out of the shear zone. (2) As to a metallogenic system with inhomogeneous volumetric change and simple shear, mineralization may occur only in structural barriers near the centre of the shear zone. (3) In a metallogenic system with homogeneous volumetric change and inhomogeneous shear, mineralization may occur in geochemical barriers both within and out of the shear zone.

  19. Four magnetite generations in the Precambrian Varena Iron Ore deposit, SE Lithuania, as a result of rock-fluid interactions

    Science.gov (United States)

    Skridlaite, Grazina; Prusinskiene, Sabina; Siliauskas, Laurynas

    2017-04-01

    Iron ores in Precambrian crystalline basement of the Varena area, SE Lithuania, were discovered during the detail geological-geophysical exploration in 1982-1992. They are covered with 210-500 m thick sediments. The Varena Iron Ore deposit (VIOD) may yield from 71 to 219.6 million tons of iron ore according to different economic evaluations (Marfin, 1996). They were assumed to be of metasomatic and hydrothermal origin, however several other hypotheses explaining the VIOZ origin, e.g. as a layered mafic or carbonatite intrusions were also suggested. Magnetites of the VIOD were thoroughly investigated by the Cameca SX100 microprobe at the Warsaw University and by the Quanta 250 Energy Dispersive Spectroscopy (EDS) at the Nature Research Centre in Vilnius, Lithuania. Four generations of magnetite were distinguished in the studied serpentine-magnetite ores (D8 drilling) and were compared with the earlier studied and reference magnetites. The earliest, spinel inclusion-rich magnetite cores (Mag-1) have the highest trace element contents (in wt%): Si (0.032), Al (0.167-0.248), Mg (0.340-0.405), Ti (0.215-0.254), V (0.090-0.138) etc. They might have formed during an early metamorphism and/or related skarn formation. Voluminous second magnetite (Mag-2) replacing olivine, pyroxenes, spinel and other skarn minerals at c. 540o C (Magnetite-Ilmenite geothermometer) has much lower trace element abundances, probably washed out by hydrothermal fluids. The latest magnetites (Mag-3 and Mag-4) overgrow the earlier ones and occur near or within the sulfide veins (Mag-4). As was observed from microtextures, the Mag-3 and Mag-4 have originated from the late thermal reworking by dissolution-reprecipitation processes. To imply an origin of the studied magnetites, they were compared to the earlier studied magmatic-metamorphic (1058 drilling), presumably skarn (982 drilling) magnetites from the studied area and plotted in the major magnetite ore type fields according to Dupuis and Beaudoin

  20. Research on Magnesite Ore Purification

    Directory of Open Access Journals (Sweden)

    Berisha, K.

    2009-12-01

    Full Text Available Magnesite ore, consisting mainly of magnesite, MgCO3 is a chief mineral source for production of high quality refractory materials based on highly pure MgO. However, the presence of calcium and silicium mineral impurities in the ore adversely affect refractoriness. The removal of silicate minerals is now a routine process but it is not so for calcium minerals impurities. In this work, the new method for the removal of calcium mineral impurities from magnesite ore has been investigated. It is based on extraction of calcium hydroxide from the calcined hydrated ore with the solution of magnesium nitrate. The results show that it is possible to remove up to 65–83 % of calcium oxide (CaO within five minutes, and up to 88–95 % within an hour. The process itself is complex, but mainly under mass transfer control. It is possible to use waste materials produced as fertilizer in agriculture thus helping in environmental protection.

  1. Origin of the Galaxy Mass-Metallicity-Star-Formation Relation

    CERN Document Server

    Harwit, Martin

    2014-01-01

    We describe an equilibrium model that links the metallicity of low-redshift galaxies to stellar evolution models. It enables the testing of different stellar initial mass functions and metal yields against observed galaxy metallicities. We show that the metallicities of more than 80,000 Sloan Digital Sky Survey (SDSS) galaxies in the low-redshift range $0.07\\leq z\\leq 0.3$ considerably constrain stellar evolution models that simultaneously relate galaxy stellar mass, metallicity, and star formation rates (SFRs) to the infall rate of low-metallicity extragalactic gas and outflow of enriched matter. A feature of our model is that it encompasses both the active star forming phases of a galaxy and epochs during which the same galaxy may lie fallow. We show that the galaxy-mass-metallicity-star-formation relation can be traced to infall of extragalactic gas mixing with native gas from host galaxies to form stars of observed metallicities, the most massive of which eject oxygen into extragalactic space. Most conseq...

  2. Geostatistical Approach to Estimating the Gold Ore Characteristics and Gold Reserves: A Case Study Daksa Area, Quang Nam Province, Viet Nam

    Science.gov (United States)

    Luan Truong, Xuan; Luong Le, Van; Quang Truong, Xuan

    2015-04-01

    Daksa gold deposit is the biggest gold deposits in Vietnam. The Daksa geological structure complicated, distributed mainly metamorphosed sedimentary NuiVu formation (PR3-?1nv2). The sulfide gold ore bodies distributed in quartz schist, quartz - biotite related to faut and distribution wing anticline. The gold ore bodies form circuits, network circuits, circuits lenses; fill the cup surface layer of the developing northeast - southwest; is the less than or west longitude north - SE. The results show that, Au and accompanying elements (Ag, Pb and Zn) have correlated pretty closely. All of its consistent with the logarithmic distribution standard, in accordance with the law of distribution of content mineral rare. The structure functions have nugget effect and spherical models with show that Au and accompanying elements special variation are changes. Au contents shown local anisotropy, no clearly anisotropy (K=1,17) and weakly anisotropy (K=1,4). Intensity mineralization of the ore bodies are quite high with demand spherical conversion coefficient ranging from 0.49 to 0.75 and from 0.66 to 0.97 (for other body). With nugget effects, ore bodies shown that it is consistent with mineralization in the ore bodies study, ore erasable, micro vein, infilling fractures in quartz vein. All of variogram presents local anisotropy, indicated gold mineralization at study area has least two-mineralization stages, consistent with the analysis of mineralography samples. By the results of the structure function study, the authors present the system optimization for exploration deposit and used to evaluate gold reserves by Ordinary Kriging. High accuracy of Kriging estimation results are expressed in the minimum Kriging variance, by compare the results calculated by some other methods (such as distance inverse weighting method, ..) and specially compare to the results of a some blocks have been exploited. Key words: Geostat and gold deposits VN. Daksa and gold mineralization. Geostat

  3. Virtual phosphorus ore requirement of Japanese economy.

    Science.gov (United States)

    Matsubae, Kazuyo; Kajiyama, Jun; Hiraki, Takehito; Nagasaka, Tetsuya

    2011-08-01

    Phosphorus is indispensable for agricultural production. Hence, the consumption of imported food indirectly implies the import of phosphorus resources. The global consumption of agricultural products depends on a small number of ore-producing countries. For sustainable management of phosphorus resources, the global supply and demand network should be clarified. In this study, we propose the virtual phosphorus ore requirement as a new indicator of the direct and indirect phosphorus requirements for our society. The virtual phosphorus ore requirement indicates the direct and indirect demands for phosphorus ore transformed into agricultural products and fertilizer. In this study, the virtual phosphorus ore requirement was evaluated for the Japanese economy in 2005. Importantly, the results show that our society requires twice as much phosphorus ore as the domestic demand for fertilizer production. The phosphorus contained in "eaten" agricultural products was only 12% of virtual phosphorus ore requirement.

  4. MAPPING CHILDREN'S POLITICS: SPATIAL STORIES, DIALOGIC RELATIONS AND POLITICAL FORMATION.

    Science.gov (United States)

    Elwood, Sarah; Mitchell, Katharyne

    2012-03-01

    This article confronts a persistent challenge in research on children's geographies and politics: the difficulty of recognizing forms of political agency and practice that by definition fall outside of existing political theory. Children are effectively "always already" positioned outside most of the structures and ideals of modernist democratic theory, such as the public sphere and abstracted notions of communicative action or "rational" speech. Recent emphases on embodied tactics of everyday life have offered important ways to recognize children's political agency and practice. However, we argue here that a focus on spatial practices and critical knowledge alone cannot capture the full range of children's politics, and show how representational and dialogic practices remain a critical element of their politics in everyday life. Drawing on de Certeau's notion of spatial stories, and Bakhtin's concept of dialogic relations, we argue that children's representations and dialogues comprise a significant space of their political agency and formation, in which they can make and negotiate social meanings, subjectivities, and relationships. We develop these arguments with evidence from an after-school activity programme we conducted with 10-13 year olds in Seattle, Washington, in which participants explored, mapped, wrote and spoke about the spaces and experiences of their everyday lives. Within these practices, children negotiate autonomy and self-determination, and forward ideas, representations, and expressions of agreement or disagreement that are critical to their formation as political actors.

  5. The Relative Effectiveness of Varied Visual Testing Formats in Retrieving Information Related to Different Educational Objectives

    Science.gov (United States)

    Williams, Jaison; Dwyer, Francis

    2004-01-01

    The purpose of this study is to: (1) examine the relative effectiveness with which different types of visual test formats facilitated information retrieval on tests measuring different educational objectives; (2) measure the effect that prior knowledge had on information retrieval; and (3) to determine whether an interaction existed between prior…

  6. EXPERIMENTAL STUDY ON THE LOAD DECAY AND ITS EFFECT ON LEAK RATE OF O-RING

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Experimental studies on load decay and leak rate of O-rings made of two kinds of silicone rubber are conducted. The results show that the characteristic of load decay is relative to the material and temperature of O-rings; the rate of load decay increases with the rise of temperature; the effects of load decay on leak rate of O-rings are negligible at room temperature, but they are notable at high temperature, and they are related to the material of O-rings. On the basis of study on the theory of load decay and analysis to the results of experiments, a theoretical model is developed to describe the load decay characteristic of O-rings, and it matches the experimental data very well. By the study of time-temperature equivalence of load decay, the interconvertting equation of test data of load decay at different temperatures is obtained.

  7. Antibiotic Resistance Related to Biofilm Formation in Klebsiella pneumoniae

    Directory of Open Access Journals (Sweden)

    Claudia Vuotto

    2014-09-01

    Full Text Available The Gram-negative opportunistic pathogen, Klebsiella pneumoniae, is responsible for causing a spectrum of community-acquired and nosocomial infections and typically infects patients with indwelling medical devices, especially urinary catheters, on which this microorganism is able to grow as a biofilm. The increasingly frequent acquisition of antibiotic resistance by K. pneumoniae strains has given rise to a global spread of this multidrug-resistant pathogen, mostly at the hospital level. This scenario is exacerbated when it is noted that intrinsic resistance to antimicrobial agents dramatically increases when K. pneumoniae strains grow as a biofilm. This review will summarize the findings about the antibiotic resistance related to biofilm formation in K. pneumoniae.

  8. Black Hole Formation and Growth: Simulations in General Relativity

    CERN Document Server

    Shapiro, Stuart L

    2007-01-01

    Black holes are popping up all over the place: in compact binary X-ray sources and GRBs, in quasars, AGNs and the cores of all bulge galaxies, in binary black holes and binary black hole-neutron stars, and maybe even in the LHC! Black holes are strong-field objects governed by Einstein's equations of general relativity. Hence general relativistic, numerical simulations of dynamical phenomena involving black holes may help reveal ways in which black holes can form, grow and be detected in the universe. To convey the state-of-the art, we summarize several representative simulations here, including the collapse of a hypermassive neutron star to a black hole following the merger of a binary neutron star, the magnetorotational collapse of a massive star to a black hole, and the formation and growth of supermassive black hole seeds by relativistic MHD accretion in the early universe.

  9. Geological characteristics and ore-forming process of the gold deposits in the western Qinling region, China

    Science.gov (United States)

    Liu, Jiajun; Liu, Chonghao; Carranza, Emmanuel John M.; Li, Yujie; Mao, Zhihao; Wang, Jianping; Wang, Yinhong; Zhang, Jing; Zhai, Degao; Zhang, Huafeng; Shan, Liang; Zhu, Laimin; Lu, Rukui

    2015-05-01

    The western Qinling, belonging to the western part of the Qinling-Dabie-Sulu orogen between the North China Block and South China Block, is one of the most important gold regions in China. Isotopic dates suggest that the Mesozoic granitoids in the western Qinling region emplaced during the Middle-Late Triassic, and the deposits formed during the Late Triassic. Almost all gold deposits in the western Qinling region are classified as orogenic, Carlin-type, and Carlin-like gold deposits, and they are the products of Qinling Orogenesis caused by the final collision between the North China Block and the South China Block. The early subduction of the Mian-Lue oceanic crust and the latter collision between South Qinling Terrane and the South China Block along the Mian-Lue suture generated lithosphere-scale thermal anomalies to drive orogen-scale hydrothermal systems. The collision-related magmatism also provided heat source for regional ore-forming fluids in the Carlin-like gold deposits. Orogenic gold deposits such as Huachanggou, Liziyuan, and Baguamiao lie between the Shang-Dan and Mian-Lue sutures and are confined to WNW-trending brittle-ductile shear zones in Devonian and Carboniferous greenschist-facies metasedimentary rocks that were highly-deformed and regionally-metamorphosed. These deposits are typical orogenic gold deposits and formed within a Late Triassic age. The deposits show a close relationship between Au and Ag. Ores contain mainly microscopic gold, and minor electrum and visible gold, along with pyrite. The ore-forming fluids were main metamorphic fluids. Intensive tectonic movements caused by orogenesis created fluid-migrating channels for precipitation locations. Although some orogenic gold deposits occur adjacent to granitoids, mineralization is not synchronous with magmatism; that is, the granitoids have no genetic relations to orogenic gold deposits. As ore-forming fluids converged into dilated fractures during the extension stage of orogenesis

  10. Mechanism research on arsenic removal from arsenopyrite ore during a sintering process

    Science.gov (United States)

    Cheng, Ri-jin; Ni, Hong-wei; Zhang, Hua; Zhang, Xiao-kun; Bai, Si-cheng

    2017-04-01

    The mechanism of arsenic removal during a sintering process was investigated through experiments with a sintering pot and arsenic-bearing iron ore containing arsenopyrite; the corresponding chemical properties of the sinter were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The experimental results revealed that the reaction of arsenic removal is mainly related to the oxygen atmosphere and temperature. During the sintering process, arsenic could be removed in the ignition layer, the sinter layer, and the combustion zone. A portion of FeAsS reacted with excess oxygen to generate FeAsO4, and the rest of the FeAsS reacted with oxygen to generate As2O3(g) and SO2(g). A portion of As2O3(g) mixed with Al2O3 or CaO, which resulted in the formation of arsenates such as AlAsO4 and Ca3(AsO4)2, leading to arsenic residues in sintering products. The FeAsS component in the blending ore was difficult to decompose in the preliminary heating zone, the dry zone, or the bottom layer because of the relatively low temperatures; however, As2O3(g) that originated from the high-temperature zone could react with metal oxides, resulting in the formation of arsenate residues.

  11. Isolation and identification of iron ore-solubilising fungus

    Directory of Open Access Journals (Sweden)

    Damase Khasa

    2010-09-01

    Full Text Available Potential mineral-solubilising fungi were successfully isolated from the surfaces of iron ore minerals. Four isolates were obtained and identified by molecular and phylogenetic methods as close relatives of three different genera, namely Penicillium (for isolate FO, Alternaria (for isolates SFC2 and KFC1 and Epicoccum (for isolate SFC2B. The use of tricalcium phosphate (Ca3(PO42in phosphate-solubilising experiments confirmed isolate FO as the only phosphate solubiliser among the isolated fungi. The bioleaching capabilities of both the fungus and its spent liquid medium were tested and compared using two types of iron ore materials, conglomerate and shale, from the Sishen Iron Ore Mine as sources of potassium (K and phosphorus (P. The spent liquid medium removed more K (a maximum of 32.94% removal, from conglomerate, than the fungus (a maximum of 21.36% removal, from shale. However, the fungus removed more P (a maximum of 58.33% removal, from conglomerate than the spent liquid medium (a maximum of 29.25% removal, from conglomerate. The results also indicated a potential relationship between the removal of K or P and the production of organic acids by the fungus. A high production of gluconic acid could be related to the ability of the fungus to reduce K and P. Acetic, citric and maleic acids were also produced by the fungus, but in lower quantities. In addition, particle size and iron ore type were also shown to have significant effects on the removal of potassium and phosphorus from the iron ore minerals. We therefore conclude that the spent liquid medium from the fungal isolate FO can potentially be used for biobeneficiation of iron ore minerals.

  12. Scaling Relations of Galactic Winds with Star Formation Rate

    Science.gov (United States)

    Tanner, Ryan; Cecil, Gerald; Heitsch, Fabian

    2017-01-01

    The galactic scale outflows generated by nuclear starbursts consist of a multiphase medium where each phase has a distinct velocity depending on the characteristics of the starburst. Using synthetic absorption lines generated from 3D hydrodynamical simulations we probe the outflow velocity of the hot, warm, and neutral gas entrained in a galactic wind. By varying the star formation rate (SFR) in our simulations, we find no correlation between the outflow velocity of the hot gas with the SFR, but we do find a correlation between the outflow velocity of both warm and neutral gas with the SFR. The scaling relation between outflow velocity and SFR only holds for low SFR until the scaling relation abruptly flattens at a SFR determined by the mass loading of the starburst. The outflow velocity of the hot gas only depends on the mass loading of the starburst and not the SFR. For low SFRs the difference between the velocity of cold gas, as measured by absorption lines of neutral or low ionized gas, may be 5-7 times lower than the velocity of the hot, highly ionized gas. The difference in velocity between the cold and hot gas for higher SFRs depends on the mass loading factor of the starburst. Thus the measured velocities of neutral or low ionized gas cannot be used to estimate the outflow velocity of the hot gas without determining the mass loading of the starburst.

  13. Formation scenarios and mass-radius relation for neutron stars

    CERN Document Server

    Zdunik, J L

    2011-01-01

    Neutron star crust, formed via accretion of matter from a companion in a low-mass X-ray binary (LMXB), has an equation of state (EOS) stiffer than that of catalyzed matter. At a given neutron star mass, M, the radius of a star with an accreted crust is therefore larger, by DR(M), than for usually considered star built of catalyzed matter. Using a compressible liquid drop model of nuclei, we calculate, within the one-component plasma approximation, the EOSs corresponding to different nuclear compositions of ashes of X-ray bursts in LMXB. These EOSs are then applied for studying the effect of different formation scenarios on the neutron-star mass-radius relation. Assuming the SLy EOS for neutron star's liquid core, derived by Douchin & Haensel (2001), we find that at M=1.4 M_sun the star with accreted crust has a radius more than 100 m larger that for the crust of catalyzed matter. Using smallness of the crust mass compared to M, we derive a formula that relates DR(M) to the difference in the crust EOS. Thi...

  14. Scaling Relations between Gas and Star Formation in Nearby Galaxies

    CERN Document Server

    Bigiel, F; Walter, F

    2010-01-01

    High resolution, multi-wavelength maps of a sizeable set of nearby galaxies have made it possible to study how the surface densities of HI, H2 and star formation rate (Sigma_HI, Sigma_H2, Sigma_SFR) relate on scales of a few hundred parsecs. At these scales, individual galaxy disks are comfortably resolved, making it possible to assess gas-SFR relations with respect to environment within galaxies. Sigma_H2, traced by CO intensity, shows a strong correlation with Sigma_SFR and the ratio between these two quantities, the molecular gas depletion time, appears to be constant at about 2Gyr in large spiral galaxies. Within the star-forming disks of galaxies, Sigma_SFR shows almost no correlation with Sigma_HI. In the outer parts of galaxies, however, Sigma_SFR does scale with Sigma_HI, though with large scatter. Combining data from these different environments yields a distribution with multiple regimes in Sigma_gas - Sigma_SFR space. If the underlying assumptions to convert observables to physical quantities are m...

  15. Terahertz-based relative positioning of aircraft flying in formation

    Science.gov (United States)

    Parker, John Scott

    This thesis introduces a new method for estimating the relative positions of aircraft flying in formation using terahertz frequency (THz) signals. We look specifically at the military precision airdrop application, where THz signals have two advantages: (1) stealth due to preferential propagation in the horizontal direction at high altitudes and (2) robustness for operations in GPS-denied environments. This thesis presents two system concepts for implementation. The first, dubbed the straight-and-level (SAL) architecture, produces high precision position estimates during straight and level flight, but suffers from systematic biases when the receiving aircraft performs a maneuver. In support of this architecture, we published the first ever paper on THz relative positioning, and introduced a new filtering method inspired by the well-known GPS Hatch Filter. The second, dubbed the refined-for-maneuvers (RFM) architecture, produces position estimates that are less precise than the SAL architecture, but have no systematic bias when the aircraft maneuver. Simulations are used to predict the performance of the architectures.

  16. Control of Rock Mechanics in Underground Ore Mining

    Science.gov (United States)

    Golik, V. I.; Efremenkov, A. B.

    2017-07-01

    Performance indicators in underground mining of thick iron fields can be insufficient since geo-mechanic specifics of ore-hosting fields might be considered inadequately, as a consequence, critical deformations and even earth’s surface destruction are possible, lowering the indicators of full subsurface use, this way. The reason for it is the available approach to estimating the performance of mining according to ore excavation costs, without assessing losses of valuable components and damage to the environment. The experimental approach to the problem is based on a combination of methods to justify technical capability and performance of mining technology improvement with regard to geomechanical factors. The main idea of decisions to be taken is turning geo-materials into the condition of triaxial compression via developing the support constructions of blocked up structural rock block. The study was carried out according to an integrated approach based on the analysis of concepts, field observations, and simulation with the photo-elastic materials in conditions of North Caucasus deposits. A database containing information on the deposit can be developed with the help of industrial experiments and performance indicators of the field can be also improved using the ability of ore-hosting fields to develop support constructions, keeping the geo-mechanical stability of the system at lower cost, avoiding ore contamination at the processing stage. The proposed model is a specific one because an adjustment coefficient of natural and anthropogenic stresses is used and can be adopted for local conditions. The relation of natural to anthropogenic factors can make more precise the standards of developed, prepared and ready to excavation ore reserves relying on computational methods. It is possible to minimize critical stresses and corresponding deformations due to dividing the ore field into sectors safe from the standpoint of geo-mechanics, and using less cost

  17. Thermodynamic Analysis of the Selective Reduction of a Nickeliferous Limonitic Laterite Ore by Hydrogen

    Science.gov (United States)

    Elliott, R.; Pickles, C. A.

    2017-09-01

    Nickeliferous limonitic laterite ores are becoming increasingly attractive as a source of metallic nickel as the costs associated with recovering nickel from the sulphide ores increase. Unlike the sulphide ores, however, the laterite ores are not amenable to concentration by conventional mineral processing techniques such as froth flotation. One potential concentrating method would be the pyrometallurgical solid state reduction of the nickeliferous limonitic ores at relatively low temperatures, followed by beneficiation via magnetic separation. A number of reductants can be utilized in the reduction step, and in this research, a thermodynamic model has been developed to investigate the reduction of a nickeliferous limonitic laterite by hydrogen. The nickel recovery to the ferronickel phase was predicted to be greater than 95 % at temperatures of 673-873 K. Reductant additions above the stoichiometric requirement resulted in high recoveries over a wider temperature range, but the nickel grade of the ferronickel decreased.

  18. Market Structure Differences Impacting Australian Iron Ore and Metallurgical Coal Industries

    Directory of Open Access Journals (Sweden)

    Kurt Lawrence

    2015-07-01

    Full Text Available Steelmaking relies on iron ore and metallurgical coal as main ingredients, the trade of which is hypothesized to theoretically change in tandem. However, strong correlation is not evident in historical trade prices of steelmaking inputs. To determine causes to this occurrence, the market factors that influence the Australian iron ore and metallurgical coal industries were studied. Data was collected over the past decade for worldwide resource production and trade quantities of crude steel, iron ore, and metallurgical coal. The data was analysed to reveal trends, allowing examination of the macroeconomic trade of metallurgical coal and iron ore with relation to worldwide and country specific steel production. It was determined that the influential growth of China’s steel production has spurred the growth of worldwide iron ore demand, which was met with increased production and supply, from Australia. The increased metallurgical coal demand has been met with increased production within China locally. Measures of supply elasticity were created for worldwide iron ore and metallurgical coal trade, where comparisons between Australia’s industries to the relevant greatest competitor were examined. The results, along with respective resource production data, highlighted the elevated competitive position that Australian iron ore producers enjoy compared to metallurgical coal producers. Trade characteristics revealed the different market structures that iron ore and metallurgical coal industries operate in, prompting a discussion of the effects these markets have on the two Australian industries.

  19. Origin and evolution of ore-forming fluids in the Hemushan magnetite-apatite deposit, Anhui Province, Eastern China, and their metallogenic significance

    Science.gov (United States)

    Luo, Gan; Zhang, Zhiyu; Du, Yangsong; Pang, Zhenshan; Zhang, Yanwen; Jiang, Yongwei

    2015-12-01

    The Middle-Lower Yangtze River Metallogenic Belt in the northern Yangtze Block is one of the most important economic mineral districts in China. The Hemushan deposit is a medium-class Fe deposit located in the southern part of the Ningwu iron ore district of the Middle-Lower Yangtze River Metallogenic Belt. The Fe-orebodies are mainly hosted in the contact zone between diorite and Triassic marble. The actinolite-phlogopite-apatite-magnetite ore shows metasomatic/filling textures and disseminated/mesh-vein structures. Based on evidences and petrographic observations, the ore-forming process can be divided into three distinct periods-the early metallogenic period (albite-diopside stage), the middle metallogenic period (magnetite stage and hematite stage), and the late metallogenic period (quartz-pyrite stage and carbonate stage). Fluid inclusion studies show four types of inclusions: type I daughter mineral-bearing three-phase inclusions (L + V + S), type II vapor-rich two-phase inclusions (L + V), type III liquid-rich two phase inclusions (L + V), and minor type IV liquid-phase inclusions (L). Apatites from the magnetite stage contain type I, type II and type III inclusions; anhydrites from the hematite stage mainly contain abundant type II inclusions and relatively less type I inclusions; quartz and calcite from the late metallogenic stage are mainly characterized by type III inclusions. Laser Raman spectroscopy and microthermometry of fluid inclusions show that the ore-forming fluids broadly correspond to unsaturated NaCl-H2O system. From the magnetite stage to the carbonate stage, the ore-forming fluids evolved from moderate-high temperature (average 414 °C), moderate salinity (average 25.01 wt.% NaCl equiv.) conditions to low temperature (average 168 °C), low salinity (average 6.18 wt.% NaCl equiv.) conditions. Hydrogen and oxygen isotopic studies indicate that the ore-forming fluid during the early stage of middle metallogenic period was mainly of magmatic

  20. Measurement of moisture in mill feed ore

    Energy Technology Data Exchange (ETDEWEB)

    Timm, A.R.; Moench, P.; Moisel, E. (Council for Mineral Technology, Randburg (South Africa))

    1985-04-01

    The control of the moisture in the feed to a mill is very important for efficient mill operation. Water is added continuously to the ore fed to a mill to maintain a suitable mix of ore and moisture in the mill. However, problems arise because of the large variation in the moisture content of the ore, which affects the efficiency of the grind. If too little moisture is present, the mill is unable to grind the ore finely enough, creating instead a thick 'porridge' that causes the mill to choke up. On the other hand, too much moisture results in inefficient grinding because the ore is flushed through the mill too quickly. Several techniques are available for measuring moisture and Mintek undertook an investigation in an attempt to develop a reliable robust moisture meter suitable for monitoring the moisture content of ore, which include the following: neutron backscattering, infrared absorption, microwaves, capacitance and moisture as a function of conductivity.

  1. Rock-magnetism and ore microscopy of the magnetite-apatite ore deposit from Cerro de Mercado, Mexico

    Science.gov (United States)

    Alva-Valdivia, L. M.; Goguitchaichvili, A.; Urrutia-Fucugauchi, J.; Caballero-Miranda, C.; Vivallo, W.

    2001-03-01

    Rock-magnetic and microscopic studies of the iron ores and associated igneous rocks in the Cerro de Mercado, Mexico, were carried out to determine the magnetic mineralogy and origin of natural remanent magnetization (NRM), related to the thermo-chemical processes due to hydrothermalism. Chemical remanent magnetization (CRM) seems to be present in most of investigated ore and wall rock samples, replacing completely or partially an original thermoremanent magnetization (TRM). Magnetite (or Ti-poor titanomagnetite) and hematite are commonly found in the ores. Although hematite may carry a stable CRM, no secondary components are detected above 580°, which probably attests that oxidation occurred soon enough after the extrusion and cooling of the ore-bearing magma. NRM polarities for most of the studied units are reverse. There is some scatter in the cleaned remanence directions of the ores, which may result from physical movement of the ores during faulting or mining, or from perturbation of the ambient field during remanence acquisition by inhomogeneous internal fields within these strongly magnetic ore deposits. The microscopy study under reflected light shows that the magnetic carriers are mainly titanomagnetite, with significant amounts of ilmenite-hematite minerals, and goethite-limonite resulting from alteration processes. Magmatic titanomagnetites, which are found in igneous rocks, show trellis, sandwich, and composite textures, which are compatible with high temperature (deuteric) oxy-exsolution processes. Hydrothermal alteration in ore deposits is mainly indicated by martitization in oxide minerals. Grain sizes range from a few microns to >100 mm, and possible magnetic state from single to multidomain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and IRM (isothermal remanent magnetization) acquisition suggest a predominance of spinels as magnetic carriers, most probably titanomagnetites with low

  2. Relation of organic and inorganic substances in formation of urolyths

    Directory of Open Access Journals (Sweden)

    A. K. Poliyenko

    2012-01-01

    Full Text Available Macro- and microscopic structural features of human urolyths have been studied to reveal the relation between organic and inorganic components and the role of the latter in the process of urolyth formation and growth. The combined study of the shape, color, surface, mineral and organic composition, and internal structure and zoning of 788 urolyths has been performed. Crystallomorphological, polarization-optical, X-ray-diffraction, electron-microscopic, chemical, neutron-activation, and computer technologies of study of the urolyth structure have been used. It has been found that macroscopic characteristics of uroluths (color, shape, surface, and size did not reflect the chemical composition of urolyths. In the structure of abundance of urolyths in Tomskand the Tomsk Region, oxalates (58% and urolyths of complex mineral composition (29%  prevail. It has been found that an urolyth is an organomineral aggregate having the internal structure formed by a rhythm of alternation of organic and inorganic layers and the character of arrangement of individual mineral crystals, and the internal structure is independent of the chemical composition of the urolyth and  uniform in urolyths of different chemical composition. The most part of urolyths has a mixed (44% or druzy (35% type of crystal arrangement and the  combined (45% or grainy (31% rhythm of alternation of organic and inorganic components.

  3. Genetic relationships between skarn ore deposits and magmatic activity in the Ahar region, Western Alborz, NW Iran

    Directory of Open Access Journals (Sweden)

    Mollai Habib

    2014-06-01

    Full Text Available Paleocene to Oligocene tectonic processes in northwest Iran resulted in extensive I-type calc-alkaline and alkaline magmatic activity in the Ahar region. Numerous skarn deposits formed in the contact between Upper Cretaceous impure carbonate rocks and Oligocene-Miocene plutonic rocks. This study presents new field observations of skarns in the western Alborz range and is based on geochemistry of igneous rocks, mineralogy of the important skarn deposits, and electron microprobe analyses of skarn minerals. These data are used to interpret the metasomatism during sequential skarn formation and the geotectonic setting of the skarn ore deposit related igneous rocks. The skarns were classified into exoskarn, endoskarn and ore skarn. Andraditic garnet is the main skarn mineral; the pyroxene belongs to the diopside-hedenbergite series. The skarnification started with pluton emplacement and metamorphism of carbonate rocks followed by prograde metasomatism and the formation of anhydrous minerals like garnet and pyroxene. The next stage resulted in retro gradation of anhydrous minerals along with the formation of oxide minerals (magnetite and hematite followed by the formation of hydrosilicate minerals like epidote, actinolite, chlorite, quartz, sericite and sulfide mineralization. In addition to Fe, Si and Mg, substantial amounts of Cu, along with volatile components such as H2S and CO2 were added to the skarn system. Skarn mineralogy and geochemistry of the igneous rocks indicate an island arc or subduction-related origin of the Fe-Cu skarn deposit.

  4. From BIF to Iron Ore - A journey from nanocrystals to huge iron ore deposits of the Hamersley Province, Australia

    OpenAIRE

    Egglseder, Mathias

    2017-01-01

    Banded iron formations (BIFs) are extraordinary rocks because they provide important information about the Precambrian atmosphere and hydrosphere, the global rise of oxygen, and they host the world’s major iron ore deposits. The unique texture and petrology of BIF, which mainly comprise alternating layers of iron oxides and chert remain poorly understood. Although the mineral assemblage is of diagenetic or metamorphic origin, BIF textures are interpreted as sedimentary st...

  5. Hageri alustas oreli taastamisega / Inge Põlma

    Index Scriptorium Estoniae

    Põlma, Inge

    2009-01-01

    1851. aastal eesti orelimeistri Carl Tantoni valmistatud ja 1892. aastal Gustav Terkmanni poolt kohendatud Hageri Lambertuse kiriku oreli restaureerimisest, ekspertiisi tegi rootsi organist Göran Grahn

  6. Chemical fingerprint of iron oxides related to iron enrichment of banded iron formation from the Cauê Formation - Esperança Deposit, Quadrilátero Ferrífero, Brazil: a laser ablation ICP-MS study

    Directory of Open Access Journals (Sweden)

    Lucilia Aparecida Ramos de Oliveira

    Full Text Available Chemical signatures of iron oxides from dolomitic itabirite and high-grade iron ore from the Esperança deposit, located in the Quadrilátero Ferrífero, indicate that polycyclic processes involving changing of chemical and redox conditions are responsible for the iron enrichment on Cauê Formation from Minas Supergroup. Variations of Mn, Mg and Sr content in different generations of iron oxides from dolomitic itabirite, high-grade iron ore and syn-mineralization quartz-carbonate-hematite veins denote the close relationship between high-grade iron ore formation and carbonate alteration. This indicates that dolomitic itabirite is the main precursor of the iron ore in that deposit. Long-lasting percolation of hydrothermal fluids and shifts in the redox conditions have contributed to changes in the Y/Ho ratio, light/heavy rare earth elements ratio and Ce anomaly with successive iron oxide generations (martite-granular hematite, as well as lower abundance of trace elements including rare earth elements in the younger specularite generations.

  7. The Forming Conditions of and Ore- searching Direction for B, Mg, Pb, Zn and Au Deposits in the Liaoji Proterozoic Rift

    Institute of Scientific and Technical Information of China (English)

    Zhu Yongzheng; Yao Fengliang

    2001-01-01

    The Liaoji Proterozoic rift is an inter- intracontinenatl rift developed from Archean granite- greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb - Zn, Au, Ag, Co and P. These deposits were formed as the result of late mobilization, transportation and concentration of the previously enriched ore - forming materials in several ore- bearing formations formed during the rift stage. So the metallogeny of these deposits in the rift shows both inheritance and new generation of the ore - forming materials. In future ore - searching practice, attentions should be paid on the studies of the ore - bearing formations in the rift, on the multiple stages of metallogeny and and on multiple derivations of the ore - forming materials.

  8. Rare earth elements, S and Sr isotopes and origin of barite from Bahariya Oasis, Egypt: Implication for the origin of host iron ores

    Science.gov (United States)

    Baioumy, Hassan M.

    2015-06-01

    Based on their occurrences and relation to the host iron ores, barites are classified into: (1) fragmented barite occurs as pebble to sand-size white to yellowish white barite along the unconformity between the Bahariya Formation and iron ores, (2) interstitial barite is present as pockets and lenses of large and pure crystals inside the iron ores interstitial barite inside the iron ores, and (3) disseminated barite occurs at the top of the iron ores of relatively large crystals of barite embedded in hematite and goethite matrix. In the current study, these barites have been analyzed for their rare earth elements (REE) as well as strontium and sulfur isotopes to assess their source and origin as well as the origin of host iron ores. Barite samples from the three types are characterized by low ΣREE contents ranging between 12 and 21 ppm. Disseminated barite shows relatively lower ΣREE contents (12 ppm) compared to the fragmented (19 ppm) and interstitial (21 ppm) barites. This is probably due to the relatively higher Fe2O3 in the disseminated barite that might dilute its ΣREE content. Chondrite-normalized REE patterns for the three barite mineralizations exhibit enrichment of light rare earth elements (LREE) relative to heavy rare earth elements (HREE) as shown by the high (La/Yb)N ratios that range between 14 and 45 as well as pronounced negative Ce anomalies varying between 0.03 and 0.18. The 87Sr/86Sr ratios in the analyzed samples vary between 0.707422 and 0.712237. These 87Sr/86Sr values are higher than the 87Sr/86Sr ratios of the seawater at the time of barite formation (Middle Eocene with 87Sr/86Sr ratios of 0.70773 to 0.70778) suggesting a contribution of hydrothermal fluid of high Sr isotope ratios. The δ34S values in the analyzed barites range between 14.39‰ and 18.92‰. The lower δ34S ratios in the studied barites compared with those of the seawater at the time of barite formation (Middle Eocene with δ34S ratios of 20-22‰) is attributed to a

  9. New data on the age of gold mineralization of the Lugokan ore cluster (Eastern Transbaikalia)

    Science.gov (United States)

    Redin, Yu. O.; Dultsev, V. F.; Nevolko, P. A.; Ponomarchuk, A. V.

    2016-08-01

    The Lugokan ore cluster is located in the southeastern part of Transbaikalia within the Aga-Borzya structural-formational zone of the Mongol-Okhotsk orogenic belt. The 40Ar/39Ar dating of K-bearing minerals of syngenetic to ore parageneses has been carried out applying stepwise heating technique: it has been demonstrated that the earliest gold-ore mineral associations are Au-pyrite-arsenopyrite (163 ±1.9 Ma) and Au-chalcopyrite (160 ±2 Ma). The later parageneses encompass the Au-polymetallic (156.3 ± 1.8 Ma) and Au-Bi (155.9 ± 4.5 Ma) one. By their ages and position in the general scheme of the Late Jurassic magmatism of Eastern Transbaikalia, the Lugokan's ore cluster gold-bearing mineral associations corresponds to the time of intrusion of the Shakhtama pluton (161 Ma) and the Porphyry Complex (159-155 Ma).

  10. Identity formation and social relations during late adolescence.

    Science.gov (United States)

    Craig-Bray, L; Adams, G R; Dobson, W R

    1988-04-01

    Theoretical assumptions outlined by Erik Erikson on psychosocial crisis resolution hypothesizes that the positive resolution of the identity crisis is predictive of more mature intimacy formation. To test this hypothesis, college-aged late adolescents (48 subjects) completed interviews and selfreport instruments measuring identity formation and degree of intimacy along with daily records of social interactions for one week. Analyses indicated a complex association between identity and intimacy formation. Comparisons were made between the exploration and commitment process of identity and the measures of intimacy formation and social interaction measures. Numerous complex sex differences were observed with several interactions between gender, exploration, commitment, and intimacy context. Findings are discussed in terms of broadening future research direction beyond the simple study of the linkage of identity and intimacy.

  11. Magnetization of exsolution intergrowths of hematite and ilmenite: Mineral chemistry, phase relations, and magnetic properties of hemo-ilmenite ores with micron- to nanometer-scale lamellae from Allard Lake, Quebec

    DEFF Research Database (Denmark)

    McEnroe, S.A.; Robinson, P.; Langenhorst, F.

    2007-01-01

    Hemo-ilmenite ores from Allard Lake, Quebec, were first studied over 50 years ago. Interest was renewed in these coarsely exsolved oxides, based on the theory of lamellar magnetism as an explanation for the high and stable natural remanent magnetizations (NRMs), 32 to 120 A/ m, reported here...

  12. Microwave enhanced recovery of nickel-copper ore: communition and floatability aspects.

    Science.gov (United States)

    Henda, R; Hermas, A; Gedye, R; Islam, M R

    2005-01-01

    A study describing the effect of microwave radiation, at a frequency of 2450 MHz, on the processes of communication and flotation of a complex sulphide nickel-copper ore is presented. Ore communication has been investigated under standard radiation-free conditions and after ore treatment in a radiated environment as a function of ore size, exposure time to radiation, and microwave power. The findings show that communication is tremendously improved by microwave radiation with values of the relative work index as low as 23% at a microwave power of 1.406 kW and after 10 s of exposure time. Communication is affected by exposure time and microwave power in a nontrivial manner. In terms of ore floatability, the experimental tests have been carried out on a sample of 75 microm in size under different exposure times. The results show that both ore concentrate recoveries and grades of nickel and copper are significantly enhanced after microwave treatment of the ore with relative increases in recovered concentrate, grade of nickel, and grade of copper of 26 wt%, 15 wt%, and 27%, respectively, at a microwave power of 1330 kW and after 30 s of exposure time.

  13. Rigid Ideals and Radicals of Ore Extensions

    Institute of Scientific and Technical Information of China (English)

    Chan Yong Hong; Tai Keun Kwak; S. Tariq Rizvi

    2005-01-01

    For an endomorphism σ of a ring R, Krempa called σ a rigid endomorphism if aσ(a) = 0 implies a= 0 for a ∈ R. A ring R is called rigid if there exists a rigid endomorphism of R. In this paper, we extend the σ-rigid property of a ring R to an ideal of R. For a σ-ideal Ⅰ of a ring R, we call Ⅰ a σ-rigid ideal if aσ(a) ∈Ⅰ implies a ∈Ⅰ for a ∈ R. We characterize σ-rigid ideals and study related properties. The connections of the prime radical and the upper nil radical of R with the prime radical and the upper nil radical of the Ore extension R[x; σ, δ], respectively, are also investigated.

  14. Geochemistry and S, Pb isotope of the Yangla copper deposit, western Yunnan, China: Implication for ore genesis

    Science.gov (United States)

    Yang, Xi-An; Liu, Jia-Jun; Cao, Ye; Han, Si-Yu; Gao, Bing-yu; Wang, Huan; Liu, Yue-Dong

    2012-07-01

    The Yangla copper deposit, situated in the middle section of Jinshajiang tectonic belt between Zhongza-Zhongdian block and Changdu-Simao block, is a representative and giant copper deposit that has been discovered in Jinshajiang-Lancangjiang-Nujiang region in recent years. There are coupled relationships between Yangla granodiorite and copper mineralization in the Yangla copper deposit. Five molybdenite samples yielded a well-constrained 187Re-187Os isochron age of 233.3 ± 3 Ma, the metallogenesis is therefore slightly younger than the crystallization age of the granodiorite. S, Pb isotopic compositions of the Yangla copper deposit indicate that the ore-forming materials were derived from the mixture of upper crust and mantle, also with the magmatic contributions. In the late Early Permian, the Jinshajiang Oceanic plate was subducted to the west, resulting in the formation of a series of gently dipping thrust faults in the Jinshajiang tectonic belt, meanwhile, accompanied magmatic activities. In the early Late Triassic, which was a time of transition from collision-related compression to extension in the Jinshajiang tectonic belt, the thrust faults were tensional; it would have been a favorable environment for forming ore fluids. The ascending magma provided a channel for the ore-forming fluid from the mantle wedge. After the magma arrived at the base of the early-stage Yangla granodiorite, the platy granodiorite at the base of the body would have shielded the late-stage magma from the fluid. The magma would have cooled slowly, and some of the ore-forming fluid in the magma would have entered the gently dipping thrust faults near the Yangla granodiorite, resulting in mineralization.

  15. Iron from Zealandic bog iron ore -

    DEFF Research Database (Denmark)

    Lyngstrøm, Henriette Syrach

    2011-01-01

    og geologiske materiale, metallurgiske analyser og eksperimentel arkæologiske forsøg - konturerne af en jernproduktion med udgangspunkt i den sjællandske myremalm. The frequent application by archaeologists of Werner Christensen’s distribution map for the occurrence of bog iron ore in Denmark (1966...... are sketched of iron production based on bog iron ore from Zealand....

  16. The Luster of Iron Ore Prices

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China battles its way out of an iron ore stalemate by finding alternative supplier After months of seesawing, China’s iron ore negotiators appear to be breaking through the tight encirclement of suppliers. On August 17, the China Iron and Steel Association (CISA) announced that Fortescue

  17. Fuzzy Comprehensive Appraisal of Concealed Ore Deposits

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the transformation from the fuzzy to the accurate process is exemplified by the Jiaodong gold ore deposits concentrated region where the mathematical analysis is used to appraise and forecast regional concealed gold ore deposits. In this sense, this paper presents a new way to the appraisal of the non-traditional mineral resources.

  18. Biomass for iron ore sintering

    Energy Technology Data Exchange (ETDEWEB)

    Zandi, M.; Martinez-Pacheco, M.; Fray, T.A.T. [Corus Research Development & Technology, Rotherham (United Kingdom)

    2010-11-15

    Within an integrated steelworks, iron ore sinter making is an energy intensive process. In recent years, biomass is becoming an attractive alternative source of energy to traditional fossil fuels such as coal. In this study, commercially available biomass materials suited to sinter making have been identified as an alternative source of fuel to coke breeze. Olive residues, sunflower husk pellets, almond shells, hazelnut shells and Bagasse pellets have been characterised and prepared for sintering. A laboratory sinter pot has been employed for studying sintering behaviour of biomass material. On average, the calorific values of selected biomass materials, on a dry basis, are about 65% of dry coke breeze. It was found that less of this energy would be available in sinter making due to the evaporation of some of the volatile matter ahead of the flame front. At a replacement rate of 25%, the crushed sunflower husk pellets showed the closest thermal profile to that of coke breeze alone in the size range of -0.8 to +0.6 mm. A specification of less than 1 mm has been recommended for the studied biomass materials when co-firing biomass with coke breeze for iron ore sintering.

  19. Transport network and flow mechanism of shallow ore-bearing magma in Tongling ore cluster area

    Institute of Scientific and Technical Information of China (English)

    DENG; Jun; WANG; Qingfei; HUANG; Dinghua

    2006-01-01

    Abundant studies revealed that shallow intrusions of the Yanshanian epoch resulted in the mass mineralization of the Tongling region. Various evidences showed there existed a concealed magma chamber at -10 km depth in the middle part of this region during Yanshanian epoch, from which the ore-forming magma was generated and then transported to the superficial layer. Yet the transport network and flow mechanism of the shallow ore-bearing magma, the key problem associ- ated with ore-forming process, was relatively little focused on. Integrate analysis of structural me- chanics, statistical fractal and geological facts suggested that NE trending high-angle fold-related thrust faults and the tessellated basement ones served as the main pathways for the shallow magma's transporting, moreover, the saddle void spaces among adjacent strata in the folds upon this fault system provided the place for magma's emplacement. So the folds in the upper part and faults in the lower part of the upper crust constituted the fluid's transport and emplacement network. During the deformation of geologic body with multi-layer structure, the layers in the upper part tended to fold when received the jacking stress from the lower part, while the lower one inclined to fault undergoing loads of the upper part. And the producing probability of this structure assemblage was highly increased in the condition, such as in the Tongling area, that the mechanic rigidity of the lower layers was stronger than that of the upper ones. For the pre-existence of fluid-conducting network, the top magma with high volatile in the magma chamber transported rapidly to the superficial layer in dyking pattern, located in the void spaces of folds, filled and reconstructed them. The sudden drop of pressure caused the fluid unmixing from the magma and mass ore-forming elements concentration. Pulse activity of the dyking may be the principal reason why magmatic bodies in the Tongling area were spatially

  20. The relation between bar formation, galaxy luminosity, and environment

    CERN Document Server

    Corsini, E M; Sanchez-Janssen, R; Aguerri, J A L; Zarattini, S

    2013-01-01

    We derive the bar fraction in three different environments ranging from the field to Virgo and Coma clusters, covering an unprecedentedly large range of galaxy luminosities (or, equivalently, stellar masses). We confirm that the fraction of barred galaxies strongly depends on galaxy luminosity. We also show that the difference between the bar fraction distributions as a function of galaxy luminosity (and mass) in the field and Coma cluster are statistically significant, with Virgo being an intermediate case. We interpret this result as a variation of the effect of environment on bar formation depending on galaxy luminosity. We speculate that brighter disk galaxies are stable enough against interactions to keep their cold structure, thus, the interactions are able to trigger bar formation. For fainter galaxies the interactions become strong enough to heat up the disks inhibiting bar formation and even destroying the disks. Finally, we point out that the controversy regarding whether the bar fraction depends on...

  1. Sulphate and arsenate minerals as environmental indicators in the weathering zones of selected ore deposits, Western Sudetes, Poland

    Science.gov (United States)

    Parafiniuk, Jan; Siuda, Rafał; Borkowski, Andrzej

    2016-09-01

    The results of a complex investigation of the sulphate and arsenate assemblages forming in the weathering zone of selected ore deposits in the Sudetes are presented. The development of the weathering zone has been characterised in the polymetallic ore deposits at Miedzianka-Ciechanowice and Radzimowice, and the pyrite deposit at Wieściszowice, which differ in the chemical compositions of the ore and barren minerals and the hydrological conditions. Secondary sulphate and arsenate mineral assemblages vary significantly among the ore deposits under study. Their crystallization is discussed, taking into consideration the stability of particular minerals and the paths of their transformation. It is shown that these minerals have great potential as indicators of weathering processes. A significant role for microorganisms in the formation of the weathering zone of the ore deposits under study is also proven.

  2. New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

    Science.gov (United States)

    Carmichael, Sarah K.; Doctor, Daniel H.; Wilson, Crystal G.; Feierstein, Joshua; McAleer, Ryan

    2017-01-01

    Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace and rare earth element (REE) geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered alluvial deposits that occur close to breccia-hosted Mn deposits in Virginia show geochemical signatures that are distinct from the breccia matrices and appear to reflect remobilization of earlier-emplaced Mn and concentration within supergene traps. Based on the proximity of all of the productive ore deposits to mapped faults or other zones of deformation, we suggest that the primary source of all of the Mn may have been deep seated, and that Mn oxides with supergene and/or biological characteristics resulted from the local remobilization and concentration of this primary Mn.

  3. Geology and isotopic composition of helium, neon, xenon and metallogenic age of the Jinding and Baiyangping ore deposits, northwest Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    XUE; Chunji(薛春纪); CHEN; Yuchuan(陈毓川); WANG; Denghong(王登红); YANG; Jianmin(杨建民); YANG; Weiguang(杨伟光); ZENG; Rong(曾; 荣)

    2003-01-01

    Both the Jinding and Baiyangping ore deposits developed in the Lanping basin, which is a Mesozoic-Cenozoic terrestrial clastic sedimentary basin. Their occurrences can easily lead many people to compare them with the Pb-Zn deposit hosted in sedimentary rocks, such as Mississippian Valley-, Sedex- and sandstone-type Pb-Zn deposits. However, the Lanping basin developed in the settings of strong tectonic activity of the continental crust, which could cause an effective material exchange between the lower crust and the upper mantle. The orebodies are clearly tectonically controlled without syngenetic features, which probably represents a new type of the sedimentary rock-hosted Pb-Zn deposit. The isotopic compositions of noble gases in ore-forming fluids indicate that 2%-32% of helium (3He/4He = 0.19 Ra-1.97 Ra) is derived from the mantle, 50.1% of neon (20Ne/22Ne = 10.45-10.83; 21Ne/22Ne = 0.03) from the mantle, and considerable amount of xenon (129Xe/130Xe = 5.84-6.86; 134Xe/130Xe = 2.26-2.71) from the mantle, which show that mantle fluids played an important role in the ore formation. The ore-forming age of 67-60 Ma obtained by Re-Os and 40Ar-39Ar dating methods is later than the host rock, which is coeval with the Himalayan alkali magmatism of the mantle source and mantle-crust source. In this paper, the mineralization of the Jinding and Baiyangping ore deposits is considered to be related to the mantle fluids which move upward with the magma or along the deep faults, and mix with the meteoritic brine in the crust to result in large-scale deposition.

  4. A Study on the Ore-forming Effect of Mantle-derived Fluid

    Institute of Scientific and Technical Information of China (English)

    Meng Qingqiang; Wu Jianfeng; Zhang Liuping

    2007-01-01

    Based on summarizing of the effect of mantle-derived fluid on the formation of ores, especially on gold ore,and with the latest investigations, such as the formation of ore from the action of shallow-deep fluid, the transportation effect of the thermal energy by mantle-derived fluid, this paper mainly aims at the effect of mantle-derived fluid on the generation of hydrocarbons. With the proof from geochemistry and fluid inclusion, it was suggested that the mantle-derived fluid not only supplied source materials for hydrocarbons, but also supplied essential energy and matter necessary for the generation of hydrocarbons. The mantle-derived fluid had a good effect, but at the same time it had an adverse effect under specific conditions, on the formation of reservoirs. This paper also discusses the future direction and significance of studying mantle-derived fluid.

  5. Precise Relative Positioning of Formation Flying Spacecraft using GPS

    NARCIS (Netherlands)

    Kroes, R.

    2006-01-01

    Spacecraft formation flying is considered as a key technology for advanced space missions. Compared to large individual spacecraft, the distribution of sensor systems amongst multiple platforms offers improved flexibility, shorter times to mission, and the prospect of being more cost effective. Besi

  6. Culturable microorganisms associated with Sishen iron ore and their potential roles in biobeneficiation.

    Science.gov (United States)

    Adeleke, Rasheed; Cloete, T E; Khasa, D P

    2012-03-01

    With one of the largest iron ore deposits in the world, South Africa is recognised to be among the top ten biggest exporters of iron ore. Increasing demand and consumption of this mineral triggered search for processing technologies, which can be utilised to "purify" the low-grade iron ore minerals that contain high levels of unwanted potassium (K) and phosphorus (P). This study investigated a potential biological method that can be further developed for the full biobeneficiation of low-grade iron ore minerals. Twenty-three bacterial strains that belong to Proteobacteria, Firmicutes, Bacteroidetes and Actinobateria were isolated from the iron ore minerals and identified with sequence homology and phylogenetic methods. The abilities of these isolates to lower the pH of the growth medium and solubilisation of tricalcium phosphate were used to screen them as potential mineral solubilisers. Eight isolates were successfully screened with this method and utilised in shake flask experiments using iron ore minerals as sources of K and P. The shake flask experiments revealed that all eight isolates have potentials to produce organic acids that aided the solubilisation of the iron ore minerals. In addition, all eight isolates produced high concentrations of gluconic acid followed by relatively lower concentrations of acetic, citric and propanoic acid. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analyses also indicated extracellular polymeric substances could play a role in mineral solubilisation.

  7. A novel stress distribution analytical model of O-ring seals under different properties of materials

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Di; Wang, Shao Ping; Wang, Xing Jian [School of Automation Science and Electrical Engineering, Beihang University, Beijing (China)

    2017-01-15

    The elastomeric O-ring seals have been widely used as sealing elements in hydraulic systems. The sealing performance of O-ring seals is related to stress distribution. The stresses distribution depends on the squeeze rate and internal pressure, and would vary with properties of O-ring seals materials. Thus, in order to study the sealing performance of O-ring seals, it is necessary to describe the analytic relationship between stress distribution and properties of O-ring seals materials. For this purpose, a novel Stress distribution analytical model (SDAM) is proposed in this paper. The analytical model utilizes two stress complex functions to describe the stress distribution of O-ring seals. The proposed SDAM can express not only the analytical relationship between stress distribution and Young’s modulus, but also the one between stress distribution and Poisson’s ratio. Finally, compared results between finite element analysis and the SDAM validate that the proposed model can effectively reveal the stress distribution under different properties for O-ring materials.

  8. Nitrile O-ring Cracking: A Case of Vacuum Flange O-ring Failures

    Energy Technology Data Exchange (ETDEWEB)

    Dees, Craig

    2016-07-01

    A review of recent nitrile O-ring failures in ISO-KF vacuum flange connections in glovebox applications is presented. An investigation of a single “isolated” o-ring failure leads to the discovery of cracked nitrile o-rings in a glovebox atmospheric control unit. The initial cause of the o-ring failure is attributed to ozone degradation. However, additional investigation reveals nitrile o-ring cracking on multiple gloveboxes and general purpose piping, roughly 85% of the nitrile o-rings removed for inspection show evidence of visible cracking after being in service for 18 months or less. The results of material testing and ambient air testing is presented, elevated ozone levels are not found. The contributing factors of o-ring failure, including nitrile air sensitivity, inadequate storage practices, and poor installation techniques, are discussed. A discussion of nitrile o-ring material properties, the benefits and limitations, and alternate materials are discussed. Considerations for o-ring material selection, purchasing, storage, and installation are presented in the context of lessons learned from the nitrile o-ring cracking investigation. This paper can be presented in 20 minutes and does not require special accommodations or special audio visual devices.

  9. Influence of Mechanical Activation on Acid Leaching Dephosphorization of High-phosphorus Iron Ore Concentrates

    Institute of Scientific and Technical Information of China (English)

    De-qing ZHU; Hao WANG; Jian PAN; Cong-cong YANG

    2016-01-01

    High pressure roll grinding (HPRG)and ball milling were compared to investigate the influence of me-chanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate,which was man-ufactured through magnetizing roasting-magnetic separation of high-phosphorus oolitic iron ores.The results indica-ted that when high-phosphorus iron ore concentrates containing 54·92 mass% iron and 0·76 mass% phosphorus were directly processed through acid leaching,iron ore concentrates containing 55·74 mass% iron and 0·33 mass%phosphorus with an iron recovery of 84·64% and dephosphorization of 63·79% were obtained.When high-phosphor-us iron ore concentrates activated by ball milling were processed by acid leaching,iron ore concentrates containing 56·03 mass% iron and 0·21 mass% phosphorus with an iron recovery of 85·65% and dephosphorization of 77·49%were obtained.Meanwhile,when high-phosphorus iron ore concentrates activated by HPRG were processed by acid leaching,iron ore concentrates containing 58·02 mass% iron and 0·10 mass% phosphorus were obtained,with the iron recovery reaching 88·42% and the dephosphorization rate reaching 88·99%.Mechanistic studies demonstrated that ball milling can reduce the particle size,demonstrating a prominent reunion phenomenon.In contrast,HPRG pretreatment contributes to the formation of more cracks within the particles and selective dissociation of iron and P bearing minerals,which can provide the favorable kinetic conditions to accelerate the solid-liquid reaction rate.As such,the crystal structure is destroyed and the surface energy of mineral particles is strengthened by mechanical ac-tivation,further strengthening the dephosphorization.

  10. Rock-forming and Ore-forming Ages as well as Formation Environments of Porphyry Molybdenum Deposits in Beishan Area, Inner Mongolia%内蒙古北山地区斑岩型钼矿的成岩成矿时代和形成环境探讨

    Institute of Scientific and Technical Information of China (English)

    杨岳清; 赵金花; 孟贵祥; 严加永; 吕博; 王守光; 贾玲珑; 韩建刚

    2013-01-01

    A nearly EW-trending molybdenum (copper) ore belt was found in Beishan area of Inner Mongolia. The relatively large deposits in this belt include Liushashan molybdenum deposit, Elegenwulanwula molybdenum deposit and Xiaohulishan molybdenum deposit., Re-Os isotope dating of molybdenite samples from these three deposits yielded isochron ages of (260±10) Ma (Middle Permian), 332.0 Ma (Early Carboniferous) and 220 Ma (Late Triassic) respectively. Obviously, different metallogenic epochs reflect different environments for the formation of these deposits. Based on new SHRIMP zircon U-Pb age data of the porphyry related to mineralization as well as basic rock and ore geochemical work, the authors revealed the formation environments of the three deposits from the angle of regional crustal evolution. In the Early Paleozoic, the three deposits were in Kazakhstan plate, and in the Late Paleozoic, due to the development of Hongshishan-Baiheshan-Pengboshan area from rift valley to ocean basin, the position of the Liushashan molybdenum deposit was split into the Tarim plate. Due to the difference in subduction mechanism and underlying basement, tectono-magmatic activities were somewhat different in two island arcs. In active marginal belt of north Tarim plate, magmatic activity was unusually strong and lasted from Carboniferous to the end of Permian. In the early stage, mineralization was dominated mainly by iron, and molybdenum (copper) deposits were formed in the late stage. Magmatic activity of the marginal belt in south Kazakhstan plate was a bit weaker than that in the northern marginal belt of Tarim plate, and the magmatic activity was mainly concentrated in Carboniferous; in such an environment, the Elegenwulanwula molybdenum deposit was formed. At the end of Permian, the split plate of Beishan area became a unified plate again through collage. From that time on, Beishan area entered into an environment of intra-continental crustal activity, and stretching

  11. Atmospheric emission of polychlorinated naphthalenes from iron ore sintering processes.

    Science.gov (United States)

    Liu, Guorui; Zheng, Minghui; Du, Bing; Nie, Zhiqiang; Zhang, Bing; Liu, Wenbin; Li, Cheng; Hu, Jicheng

    2012-10-01

    Iron ore sintering processes constitute significant sources of dioxins, and studies have confirmed a close correlation between polychlorinated naphthalenes (PCNs) and dioxin formation. Thus, iron ore sintering processes are thought to be a potential source of PCNs, although intensive investigations on PCN emissions from sintering processes have not been carried out. Therefore, the aim of the present study was to qualify and quantify PCN emissions from nine sintering plants operating on different industrial scales. PCN concentrations ranged from 3 to 983 ng m(-3) (0.4-23.3 pg TEQ(PCN) m(-3)) and emission factors ranged from 14 to 1749 μg t(-1) (0.5-41.5 ng TEQ(PCN) t(-1)), with a geometric mean of 84 μg t(-1) (2.1 ng TEQ(PCN) t(-1)). The estimated annual emission of PCNs from sintering processes in China was 1390 mg TEQ(PCN). These figures will assist in the development of a PCN emissions inventory. Regarding emission characteristics, PCNs mainly comprised low-chlorinated homologs. The ratios of several characteristic PCN congeners were also measured and compared with those from other sources. Taken together, these results may provide useful information for identifying the sources of PCNs produced by iron ore sintering processes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Chemical and mineralogical characterization of chromite ore processing residue from two recent Indian disposal sites.

    Science.gov (United States)

    Matern, Katrin; Kletti, Holger; Mansfeldt, Tim

    2016-07-01

    Chromite ore processing residue (COPR) is a hazardous waste. Nevertheless, deposition of COPR in uncontrolled surface landfills is still common practice in some countries. Whereas old (between at least 40 and 180 years) COPR from the temperate zone has been intensively investigated, information on COPR in other regions is restricted. Relatively young (ore processing and preventing the migration of Cr(VI) into water bodies are the main challenges when dealing with these COPR.

  13. Uranium recovery from Uro area phosphate ore, Nuba Mountains, Sudan

    Directory of Open Access Journals (Sweden)

    Abdelmajid A. Adam

    2014-11-01

    Full Text Available This study was carried out in a laboratory scale to recover uranium from Uro area phosphate ore in the eastern part of Nuba Mountains in Sudan. Phosphate ore samples were collected, and analyzed for uranium abundance. The results showed that the samples contain a significant concentration of uranium with an average of 310.3 μg/g, which is 2.6 times higher than the world average of phosphate. The green phosphoric acid obtained from the samples was found to contain uranium in the range of 186–2049 μg/g, with an average of 603.3 μg/g, and about 98% of uranium content of the phosphate ore was rendered soluble in the phosphoric acid. An extraction process using 25% tributylphosphate, followed by stripping process using 0.5 M sodium carbonate reported that more than 98% of uranium in the green phosphoric acid exists as uranyl tricarbonate complex, moreover, sodic decomposition using 50% sodium hydroxide showed that about 98% of the uranium was precipitated as sodium diuranate concentrate that is known as the yellow cake (Na2U2O7. Further purification and calcinations of the yellow cake led to the formation of the orange powder of uranium trioxide (UO3. The chemical analysis of the obtained uranium concentrates; yellow cake and uranium trioxide proved their nuclear purity and that they meet the standard commercial specification. The obtained results proved that uranium from Uro phosphate ore was successfully recovered as uranium trioxide with an overall recovery percentage of 93%.

  14. A Study on the Geological—Geochemical Dynamics of Hydrothermal Ore Deposition as Exemplified by the Muping—Rushan Gold Deposit Belt,Eastern Shandong,China

    Institute of Scientific and Technical Information of China (English)

    赵伦山; 高太忠; 等

    1996-01-01

    This paper presents a method of establishing a hydrothermal ore-forming reaction system.On the basis of the study of four typical hydrothermal deposits,the following conclusions concerning geochemical dynamic controlling during hydrothermal mineralization have been sions concerning geochemical dynaamic controlling during hydrothermal mineralization have been drawn:(1)The regional tectonic activities control the concentration and dispersion of elements in the ore-forming process in terms of their effects on the thermodynamic nature and conditions of the ore-forming reaction system.(2)During hydrothermal mineralization the activites of ore-bearing faults can be divideb into two stages:the brittle splitting stage and the brittle-tough tensing stage,which would create characteristically different geodynamic conditions for the geochemical thermodynamic ore-forming system.(3)The hydrothermal ore-forming reaaction system is an open dynamic system.At the brittle splitting stage the system was so strongly supersaturated and unequilibrated as to speed up and enhance the crystallization and differentiation of ore-forming fluids.And at the brittle-tough tensing stage,the ore-forming system was in a weak supersaturated state;with decreasing temperature and pressure the crystallization of oreforming material would show down,and it can be regarded as an equilibrated state.(4)In the lates stages of hydrothermal evolution,gold would be concentrated in the residual ore-forming solution.The pulsating fracture activite in this stage led to the crush of pyrite ore and it was then filled with gold-enriched solution,forming high-grage“fissure”gold ore.This ore-forming process could be called the coupling mechanism of ore formation.

  15. Ferrite grade iron oxides from ore rejects

    Indian Academy of Sciences (India)

    K S Rane; V M S Verenkar; P Y Sawant

    2001-06-01

    Iron oxyhydroxides and hydroxides were synthesized from chemically beneficiated high SiO2/Al2O3 low-grade iron ore (57.49% Fe2O3) rejects and heated to get iron oxides of 96–99.73% purity. The infrared band positions, isothermal weight loss and thermogravimetric and chemical analysis established the chemical formulas of iron-oxyhydroxides as -FeOOH.0.3H2O; -FeOOH.0.2H2O and amorphous FeOOH. The thermal products of all these were -Fe2O3 excepting that of -FeOOH.0.3H2O which gave mainly -Fe2O3 and some admixture of -Fe2O3. The hydrazinated iron hydroxides and oxyhydroxides, on the other hand, decomposed autocatalytically to mainly -Fe2O3. Hydrazine method modifies the thermal decomposition path of the hydroxides. The saturation magnetization, s, values were found to be in the range 60–71 emu g–1 which are close to the reported values for -Fe2O3. Mechanism of the -Fe2O3 formation by hydrazine method is discussed.

  16. Role of hydrodynamic factors in controlling the formation and location of unconformity-related uranium deposits: insights from reactive-flow modeling

    Science.gov (United States)

    Aghbelagh, Yousef Beiraghdar; Yang, Jianwen

    2017-03-01

    The role of hydrodynamic factors in controlling the formation and location of unconformity-related uranium (URU) deposits in sedimentary basins during tectonically quiet periods is investigated. A number of reactive-flow modeling experiments at the deposit scale were carried out by assigning different dip angles and directions to a fault and various permeabilities to hydrostratigraphic units). The results show that the fault dip angle and direction, and permeability of the hydrostratigraphic units govern the convection pattern, temperature distribution, and uranium mineralization. A vertical fault results in uranium mineralization at the bottom of the fault within the basement, while a dipping fault leads to precipitation of uraninite below the unconformity either away from or along the plane of the fault, depending on the fault permeability. A more permeable fault causes uraninite precipitates along the fault plane, whereas a less permeable one gives rise to the precipitation of uraninite away from it. No economic ore mineralization can form when either very low or very high permeabilities are assigned to the sandstone or basement suggesting that these units seem to have an optimal window of permeability for the formation of uranium deposits. Physicochemical parameters also exert an additional control in both the location and grade of URU deposits. These results indicate that the difference in size and grade of different URU deposits may result from variation in fluid flow pattern and physicochemical conditions, caused by the change in structural features and hydraulic properties of the stratigraphic units involved.

  17. Sulfur, Lead, Carbon and Oxygen Isotope Composition and Source of Ore-forming Materials of the Bangpu Pb-Zn Ore Deposit in Tibet%西藏邦铺铅锌矿床S、Pb、C、O同位素组成及成矿物质来源研究

    Institute of Scientific and Technical Information of China (English)

    王立强; 罗茂澄; 袁志洁; 陈伟; 冷秋锋; 张学全

    2012-01-01

    The Bangpu Pb-Zn deposit, formed in the periphery of the porphyry mineralization body of the ore district, is a skarn deposit with relatively rich ore grade, and the ore-forming elements are dominated by lead and zinc, without copper basically. Main metal sulfides were objects of this study, and S and Pb isotopic methods were used to investigate the source of the ore-forming minerals. The results show that the δ34S values of the ore metal sulfides have a wide distribution, and mainly vary in the range of -3.7‰-0.7‰, with the characteristics of tower distribution, and that these sulfur materials were mainly derived from the magma. Lead isotopes of the ore have stable composition and are positive common lead. The high μ values (larger than 9.58) of ore lead and the distribution characteristics of the data points in the evolution diagram of tectonic environment indicate that the ore lead was mainly derived from the upper crust. A comparison between this deposit and the nearby Zhibula and Jiama deposits shows that sulfur of these three deposits was exclusively derived from magma, and their metal materials show a certain regular pattern in source space, i.e., the contamination of crustal source material increased from south to north in the Qulong-Jiama-Bangpu ore district. Carbon and Oxygen isotope compositions of marble and calcite show that carbon in ore-forming fluid was mainly derived from the magma whereas the carbonate formation provided parts of other ore-forming materials.%邦铺铅锌矿床系邦铺钼铜矿区斑岩矿化体外围形成的矽卡岩型铅锌矿床;矿石品位较富,成矿元素以铅锌为主,基本不含铜.文章以矿床中主要金属硫化物为研究对象,采用S、Pb同位素研究方法对矿床成矿物质来源进行探讨.结果表明,矿石金属硫化物δ34S值分布范围较宽,但主要集中于-3.7‰~-0.7‰之问,具塔式分布特征,硫主要来源于岩浆;矿石铅同位素组成稳定,

  18. Motivation alters impression formation and related neural systems.

    Science.gov (United States)

    Hughes, Brent L; Zaki, Jamil; Ambady, Nalini

    2017-01-01

    Observers frequently form impressions of other people based on complex or conflicting information. Rather than being objective, these impressions are often biased by observers' motives. For instance, observers often downplay negative information they learn about ingroup members. Here, we characterize the neural systems associated with biased impression formation. Participants learned positive and negative information about ingroup and outgroup social targets. Following this information, participants worsened their impressions of outgroup, but not ingroup, targets. This tendency was associated with a failure to engage neural structures including lateral prefrontal cortex, dorsal anterior cingulate cortex, temporoparietal junction, Insula and Precuneus when processing negative information about ingroup (but not outgroup) targets. To the extent that participants engaged these regions while learning negative information about ingroup members, they exhibited less ingroup bias in their impressions. These data are consistent with a model of 'effortless bias', under which perceivers fail to process goal-inconsistent information in order to maintain desired conclusions.

  19. Relations entre tectonique globale et déformations intraplaques Relations Between Global Tectonics and Intraplate

    Directory of Open Access Journals (Sweden)

    Poulet M.

    2006-11-01

    Full Text Available C'est dans le domaine continental intraplaque que les applications de la tectonique globale intéressent le plus les géologues pétroliers mais c'est aussi dans ce domaine que sa réalité est la plus difficile à percevoir. Après un bref rappel des concepts de base de la tectonique globale et de la structure de la lithosphère, on fait le point des connaissances acquises à ce jour sur les principaux paramètres intervenant lors des déformations intraplaques - les déplacements absolus des plaques qui conditionnent les relations entre phénomènes profonds et déformations de surface ; - les hétérogénéités de la croûte terrestre qui introduisent des déséquilibres mécaniques - dissymétrie de structure des marges stables, - variations d'épaisseur et de composition chimique de la croûte continentale, - modifications des charges lithostatiques par sédimentation ou érosion. - les phénomènes thermiques qui n'apparaissent pas, sauf pour les marges stables, directement en relation avec la tectonique globale mais avec la géométrie de la lithosphère continentale mal connue à ce jour; - les forces motrices ou résistantes responsables du mouvement des plaques c'est en réalité l'étude des déformations actuelles qui doit permettre de tester la validité des mécanismes proposés par la tectonique globale. Ces mécanismes, une fois établis, permettront une meilleure compréhension des déformations passées affectant le sédimentaire dans la mesure où l'on tient compte des hétérogénéités anciennes du substratum. Après cet examen critique, on présente en conclusion un exemple concret, l'évolution structurale des grabens rhénans, évolution qui résulte de l'influence conjuguée des trois facteurs précédemment examinés : phénomènes thermiques, hétérogénéité de la croûte, mouvement des plaques. The intraplate continental realm is where the applications of global tectonics are of mostinterestta petroleum

  20. REE Characteristics of Microfine Disseminated Gold Ores in Danzai,Guizhou

    Institute of Scientific and Technical Information of China (English)

    陈庆年; 周丕康; 等

    1998-01-01

    Described in this paper are the fundamental characteristics of mineralization of gold ores in the Sandu-Danzhai Hg-Sb-Au ore belt of Guizhou Province,Through systematic sampling of the industrial orebody and alteration zone,the total amount of the rare-earth elements,that of the light rare-earth elements,Eu depletion and other parameters are clarified.There have been distinguished two types of REE distribution patterns:the"Clay type"and the "quartz type" .High-grade orebodies are closely related with silicification,illitization and pyritization.The seven-component diagram of the REEs of even numbers in the periodic table(Bal-asov,1966)is capable of distinguishing ore-bearing from ore-barren deposits.

  1. A Study of Occurrences of Ag in Pb-Zn-Cu Ore Deposits in China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A systematic study of occurrences of silver in 156 Pb-Zn-Cu ore deposits indicates that silver mainly occurs in nonferrous metal ore deposits in forms of association and paragenesis. It occurs mainly as independent minerals in nature and occasionally as ion adsorption, isomorphous or amorphous silver minerals. Nearly 190 silver minerals have been discovered in China. Their shapes, constituents, textures, grain sizes, embedded types, distribution patterns, mineral assemblages and metallogenic series suggest that these characteristics are closely related to geneses of deposits and dependent of ore-forming conditions. Pb, Zn and Cu sulphides are the main carrier minerals of silver. The partition of silver in ore is constrained by the mineralization intensity, grain size and embedded form of silver minerals and mineral assemblages.

  2. Geological Characteristics of Epithermal Ore Concentrated Areas and Epithermal Ore Deposits in China

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and tectonics, and discuss the relationship between distributed characteristics of the epithermal ore deposits and ore-control factors in this paper. It is concluded that the conditions, under which the epithermal ore deposits form, are huge thick basement of Proterozoic, long-time and wide-scope developed capping bed and weak magmatic activity. The basement of Proterozoic that enriches volcanic matters and carbon and the carbonaceous-bearing and paleo-pool-bearing capping bed provides main ore source. The large and deep faults and paleopool accordance with gravity anomaly gradient control the distribution of epithermal ore deposits. The lithologic assembles of microclastic rocks and carbonate rocks in the capping bed provide spaces of ore precipitation and create conditions of ore precipitation. The coincidence of many geological factors above forms the epithermal ore concentrated area.

  3. Ore body shapes versus regional deformation patterns as a base for 3D prospectivity mapping in the Skellefte Mining District, Sweden

    Science.gov (United States)

    Bauer, T.; Skyttä, P.; Hermansson, T.; Weihed, P.

    2012-04-01

    The current work in progress is based on detailed structural analysis carried out during the last years, which unravels the crustal evolution of the ore bearing Palaeoproterozoic Skellefte District in northern Sweden. The shape and orientation of the volcanic-hosted massive sulfide (VMS) ore bodies through the district is modeled in three dimensions and reflected against the regional deformation patterns. By doing this we aim to understand the coupling between the transposition of the ore bodies and the deformation structures in the host rocks, honoring both local deformation features and regional structural transitions. The VMS ore bodies are modeled in gOcad (Paradigm) visualizing both the strike and dip of the ore lenses as well as their dimensions. 25 deposits are currently available in 3D and modelling of the remaining 55 deposits is planned or partly in progress. The ore deposits and mineralizations are classified according to their shape and size. The complexly deformed ore bodies are described each independently. Subsequently, the VMS deposits are plotted on the structural map of the Skellefte district displaying their size and strike, dip and plunge values in order to show their spatial distribution and their relationship with shear zones. The preliminary results show a good correlation between the shape and orientation of the ore bodies and the related structures. Plotting the VMS deposits on a structural map clearly demonstrates the close spatial relation of the ore deposits and regional scale shear zones. Furthermore, the deformation style within the ore deposits generally mimics the deformation style of the shear zones, e.g. the plunge of elongate ore bodies parallels the mineral lineation of the related shear zone. Based on these results, the location and shape of ore deposits may be estimated, which is an important tool for prospectivity mapping and near mine exploration of ore districts.

  4. 铀矿大型矿集区与成矿作用%Large ore-concentrated area of uranium deposits and uranium metellogeny

    Institute of Scientific and Technical Information of China (English)

    仉宝聚

    2001-01-01

    The formation of large ore-concentated are results from the anomalous concentration of multi-mineral resources and large amount of ore materials during the process of geologic evolution history. Different ore-concentrated areas are characterized by different typical mineral resources and typical ore deposits. This paper, taking uranium deposit as on example, recognizes 14 large ore-concentrated areas of uranium deposit in the world, and studies the time-space constraints of large ore-concentrated areas of uranium deposits and their relation with geodynamic evolution, and on the above basis, discusses the unusual concentration of ore elements in large ore-concentrated areas of uranium deposits, as well as proposes the characteristics of “unusual concentration in certain points and areas” and “explosion metallogeny in a short period of time” of multiple mineral resources. According to the three basic “links”, i.e. “source, transportation and precipitation”, this paper proposes the metallogeny of large ore-concentrated areas of uranium deposits. Of them, the study on the deep-source metallogeny, water-rock intereaction of special alkaline fluid and precipitation environment has made a fundation for the establishment of prospecting model of large uranium ore-concentration arcas.%大型矿集区的形成,是在地质历史演化进程中,多矿种大矿量超常聚集的结果。不同的矿集区有不同的典型矿种和典型矿床。本文仅以铀矿为例,在世界范围内厘定出14个铀矿大型矿集区。本文研究铀矿大型矿集区时空分布规律与地球动力学演化的关系,在此基础上探讨了铀矿大型矿集区元素超常聚集规律,提出多矿种“点区超常聚集”和“短时限爆发成矿”特征。本文按照“源、运、积”3个环节,探讨铀矿大型矿集区的成矿作用,其中有关深源成矿、特殊碱质流体的水岩反应以及元素淀积环境的研究,为建立铀

  5. The sources of our iron ores. II

    Science.gov (United States)

    Burchard, E.F.

    1933-01-01

    In this instalment** the iron ore deposits of the Lake Superior States, which normally furnish about 80 per cent, of the annual output of the United States, are described together with historical notes on discovery and transportation of ore. Deposits in the Mississippi Valley and Western States are likewise outlined and the sources of imported ore are given. Reviewing the whole field, it is indicated that the great producing deposits of the Lake Superior and southern Appalachian regions are of hematite in basin areas of sedimentary rocks, that hydrated iron oxides and iron carbonates are generally found in undisturbed comparatively recent sediments, and that magnetite occurs in metamorphic and igneous rocks; also that numerical abundance of deposits is not a criterion as to their real importance as a source of supply. Statistics of production of iron ore and estimates of reserves of present grade conclude the paper.

  6. Understanding Lateritic Ore Agglomeration Behaviour as a ...

    African Journals Online (AJOL)

    user

    istics, low grade lateritic ores require more aggressive but costly chemical and hydrometallurgical techniques (e.g., leaching in ... Isothermal, batch agglomeration tests involving 30 and 44 % w/w sulphuric acid ... *Loss of ignition. Table 2: ...

  7. Research of Geochemical Associations of Nephelin Ores

    Science.gov (United States)

    Vulf, M.; Simonov, K.; Sazonov, A.

    The instant paper concerns research of distribution petrogenic chemical members in urtit ore body of Kia-Shaltyrsk deposit. Rocks of the deposit are ore for producing alum earth. Actuality of the subject based on outlooks of detection noble metal ore-bearing (Au, Pt, Pd, Rh, Ru) in alkaline rocks of Siberia, including rocks of Kia-Shaltyrsk deposit (Kuznetsk Alatau). The main purpose of analysis of distribution of members is directed to detection of a non-uniformity of distribution of substance and segments enriched with alum earth and noble members. The basic solved problems are following: o Creation regression models of ore body; o Definition of cumulative distribution functions of members in a contour of ore body; o The analysis of the obtained outcomes in geologic terms. For construction regression models the full-scale data was used, which was presented by the results of the spectral and silicate analyses of gold and petrogenic members containing 130 assays arranged in ore body. A non-linear multiparameter model of the ore body based on components of nephelin ore using neural net approach was constructed. For each member the corresponding distribution function is produced. The model is constructed on the following members: Au, Al2O3, SiO2, Fe2O3, CaO, MgO, SO3, R2O ((Na2O+K2O) -1) and losses of burning. The error of model forecasting membersS concentrations was from 0.02 up to 20%. Large errors basically connected with assays located near contact of ore body and ad- jacent strata or with very high concentrations of members; also they can be connected with different genesis of rocks or superposition of other processes. The analysis of concentrations of members and normalised absolute errors of the fore- cast has shown, that all members can be sectioned into two groups: first: Al2O3, SiO2, R2O, Fe2O3 and second: Au, losses of burning, CaO, MgO, SO3. The distribution of 1 gold is tightly connected with calcium and losses of burning and spatially linked with zones

  8. Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

    Science.gov (United States)

    Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

    1999-01-01

    The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep

  9. Assessment of soda ash calcination treatment of Turkish trona ore

    Directory of Open Access Journals (Sweden)

    Gezer Sibel

    2016-01-01

    Full Text Available Trona is relatively rare, non-metallic mineral, Na2CO3 · NaHCO3 · 2H2O. The pure material contains 70.3% sodium carbonate and by calcination the excess CO2 and water can be driven off, yielding natural soda ash. The terms soda ash and sodium carbonate are used interchangeably. Trona calcining is a key process step in production of soda ash (sodium carbonate anhydrate from the relatively cheap trona ore. The calcination reaction may proceeds in a sequence of steps. Depending on the conditions, it may result in formation of either sodium carbonate monohydrate (Na2CO3 · H2O, sodium sesquicarbonate or weigschederite (Na2CO3 · 3NaHCO3. The Beypazarı Turkish trona deposit is the second largest deposit in the world with the content of 84% trona. The decomposition of trona appeared to be a single stage process across the temperature range studied (150-200 °C with the representative samples of different size fractions in the draught up metallurgical furnace. The optimum particle size and calcination time were −6.35 mm and 30 minutes, respectively, at calcination temperature of 175 °C in a metallurgical furnace. Microwave-induced dry calcination of trona was possible and 5 minutes of calcination time at a power level of 900 was sufficient for complete calcination of −6.35 mm feed. This includes short time calcinations with the goal of improving economics and simplifying the thermal process.

  10. Clues on galaxy and cluster formation from their scaling relations

    CERN Document Server

    Lanzoni, B; Cappi, A; Tormen, G; Zamorani, G

    2003-01-01

    By means of high-resolution N-body simulations in a LambdaCDM cosmology, we verify that scaling relations similar to those observed for nearby galaxy clusters are also defined by their dark matter hosts; the slopes, however, are not the same. We then show that the scaling relations of galaxy clusters can be explained as the result of the cosmological collapse of density fluctuations at the appropriate scales, plus a systematic trend of the M/L ratio with cluster mass. The empirical fact that the exponent of the Faber-Jackson relation of elliptical galaxies is significantly different (higher) than that of clusters, force us to conclude that the galaxy scaling laws might derive from the cosmological collapse of density fluctuations at the epoch when galactic scales became non-linear, plus modifications afterward due to early-time dissipative merging.

  11. Flotation studies on low grade graphite ore from eastern India

    Institute of Scientific and Technical Information of China (English)

    Vasumathi N.; Vijaya Kumar T.V.; Ratchambigai S.; Subba Rao S.; Bhaskar Raju G

    2015-01-01

    A low grade graphite ore from eastern India was beneficiated by flotation to improve its quality. The ore was composed of 87.80%ash and 8.59%fixed carbon. Primary coarse wet grinding (d80:186 lm) followed by rougher flotation in Denver flotation cell using diesel as collector and pine oil as frother yielded a rougher concentrate. Regrinding (d80:144 lm) of this rougher concentrate was opted for further libera-tion of graphite. It was followed by cleaning in laboratory flotation column. This combined process of relatively coarse primary grinding followed by regrinding and cleaning in flotation column resulted in final concentrate of 7.44% yield with 89.65% fixed carbon and 6.00% ash. This approach of two-stage grinding to recover the flake graphite at the coarsest possible grind can help to minimize grinding energy costs. A conceptual flow sheet which is cost effective was developed based on this methodology.

  12. Uranium-bearing lignite and its relation to the White River and Arikaree formations in northwestern South Dakota and adjacent states

    Science.gov (United States)

    Denson, N.M.; Bachman, G.O.; Zeller, H.D.

    1954-01-01

    In northwestern South Dakota and adjacent areas uranium-bearing lignite beds occur at many horizons in the Hell Creek formation of late Cretaceous age and the overlying Ludlow, Tongue River, and Sentinel Butte members of the Fort Union formation of Paleocene age. Uranium analyses of 275 surface and auger samples and about 1,000 core samples show that many of the lignite beds contain 0. 005 to 0. 02 percent uranium with concentrations of 0. 05 to 0.10 percent uranium in the lignite ash. Analytical data indicate that the region contains an aggregate of at least 47,500, 000 tons of lignite with an average grade of slightly more than .0. 008 percent containing 3, 900 tons of uranium. Almost a fifth of the estimated reserves are adapted to strip mining and are in beds averaging about 4 feet in thickness. Uranium concentrations of this magnitude in lignite indicate that these deposits upon the development of proper utilization techniques and processes may be an important future source of uranium. Recent discoveries of ore-grade deposits of autunite-bearing lignite and secondary uranium minerals in carbonaceous sandstone at Cave Hills and Slim Buttes indicate that northwestern South Dakota and adjacent areas may containimportant reserves of uranium-ore. The stratigraphic units containing the uraniferous lignite beds have a combined thickness of about 1, 500 feet and are unconformably overlapped by 300 feet or more of tuffaceous sandstone and bentonitic claystone of the White River and Arikaree formations of Oligocene and Miocene age. The stratigraphically highest lignite beds in the local sequence have the greatest concentration of uranium,, and the uranium content is greatest at the top of thick lignite beds, diminishing progressively downward to a vanishing point in their lower parts. Variations in permeability of the rock overlying the mineralized lignite beds seem to be reflected in the intensity of uranium mineralization. Most of the known uranium-bearing lignite

  13. Biomining: metal recovery from ores with microorganisms.

    Science.gov (United States)

    Schippers, Axel; Hedrich, Sabrina; Vasters, Jürgen; Drobe, Malte; Sand, Wolfgang; Willscher, Sabine

    2014-01-01

    Biomining is an increasingly applied biotechnological procedure for processing of ores in the mining industry (biohydrometallurgy). Nowadays the production of copper from low-grade ores is the most important industrial application and a significant part of world copper production already originates from heap or dump/stockpile bioleaching. Conceptual differences exist between the industrial processes of bioleaching and biooxidation. Bioleaching is a conversion of an insoluble valuable metal into a soluble form by means of microorganisms. In biooxidation, on the other hand, gold is predominantly unlocked from refractory ores in large-scale stirred-tank biooxidation arrangements for further processing steps. In addition to copper and gold production, biomining is also used to produce cobalt, nickel, zinc, and uranium. Up to now, biomining has merely been used as a procedure in the processing of sulfide ores and uranium ore, but laboratory and pilot procedures already exist for the processing of silicate and oxide ores (e.g., laterites), for leaching of processing residues or mine waste dumps (mine tailings), as well as for the extraction of metals from industrial residues and waste (recycling). This chapter estimates the world production of copper, gold, and other metals by means of biomining and chemical leaching (bio-/hydrometallurgy) compared with metal production by pyrometallurgical procedures, and describes new developments in biomining. In addition, an overview is given about metal sulfide oxidizing microorganisms, fundamentals of biomining including bioleaching mechanisms and interface processes, as well as anaerobic bioleaching and bioleaching with heterotrophic microorganisms.

  14. How Many Ore-Bearing Asteroids?

    CERN Document Server

    Elvis, Martin

    2013-01-01

    A simple formalism is presented to assess how many asteroids contain ore, i.e. commercially profitable material, and not merely a high concentration of a resource. I apply this formalism to two resource cases: platinum group metals (PGMs) and water. Assuming for now that only Ni-Fe asteroids are of interest for PGMs, then 1% of NEOs are rich in PGMs. The dearth of ultra-low delta-v (= US$1 B and the population of near-Earth objects (NEOs) larger than 100 m diameter is ~20,000 (Mainzer et al. 2011) the total population of PGM ore-bearing NEOs is roughly 10. I stress that this is a conservative and highly uncertain value. For example, an order of magnitude increase in PGM ore-bearing NEOs occurs if delta-v can as large as 5.7 km s-1. Water ore for utilization in space is likely to be found in ~1/1100 NEOs. NEOs as small as 18 m diameter can be water-ore-bodies because of the high richness of water (~20%) expected in ~25% of carbonaceous asteroids, bringing the number of water-ore-bearing NEOs to ~9000 out of th...

  15. Some features of mineralization and magnetism of the Kara ore field according to Pb-isotopic data

    Energy Technology Data Exchange (ETDEWEB)

    Spiridonov, A.M.; Fefelov, N.N.; Petrovskaya, S.G.; Gnilusha, V.A.; Solodyankina, V.N.

    1986-01-01

    The genetic nature of the Kara are field, being a part of the gol - molybdenum zone of the East Transbaikal region, is considered. The lead isotopic composition of mineralization represented by veins, ore and metasomatic zones with vein-impregnate mineralization of gold-sulphide-quartz formation is measured. Investigations of the lead isotopic composition permit to connect the mineralization of the Kara ore field with magmatites of the shoshonitelatite series.

  16. 湖南省常宁市狮形岭锡矿区地质特征及控矿因素分析%Analysis on the ore controlling factors and geological features of Shixingling tin mining area in Changning city,Hunan province

    Institute of Scientific and Technical Information of China (English)

    宁勇云

    2014-01-01

    狮形岭锡矿赋存于大义山复式花岗岩体内,矿化类型以云英岩脉型为主。通过矿区地质特征的研究,在构造、岩浆岩、蚀变等方面分析矿脉控矿因素。郴州-邵阳 NW向深断裂带及“大义山式断裂构造带”形成的次级断裂构成了深断裂控矿-区域性断裂导矿-次级断裂容矿的构造成矿配套体系;岩浆岩,特别是晚期介头单元为矿区成矿母岩,与锡矿形成密切相关,为矿体形成提供成矿物质及热源。%The Shixingling tin deposit,a greisen mineralization type,is located in the Dayishan granite body. The study is focus on the geological characteristics,ore controlling factors with the analysis of vein struc-ture,magmatite,alteration,etc.Chenzhou-Shaoyang deep fracture zone in NW and"secondary fracture fault of Dayishan trend tectonic belt"formed a metallogenic system of which deep fault as ore controll region-al faults as lead ore structure,and the secondary faults as ore bearing structure.The magmatite,especially the advanced medium head unit of the ore-forming mother rock,is closely related to the formation of ore bodies.It provided ore-forming material and heat source as well.

  17. Genesis of ion-adsorption type REE ores in Thailand

    Science.gov (United States)

    Sanematsu, K.; Yoshiaki, K.; Watanabe, Y.

    2012-04-01

    Ion-adsorption type REE deposits, which have been economically mined only in southern China, are predominant supply sources for HREE in the world. The ore bodies consist of weathered granites called ion-adsorption ores. The majority of REE (>50 %) are electrostatically adsorbed onto weathering products in the ores and they can be extracted by ion exchange using an electrolyte solution (e.g., ammonium sulfate solution). Recently the occurrences of ion-adsorption ores have been reported in Indochina, SE Asia. In this study, we discuss geochemical and mineralogical characteristics of parent granites and weathered granites in Thailand in order to reveal the genesis of ion-adsorption ores. Permo-Triassic and Cretaceous-Paleogene granite plutons are distributed from northern Thailand to western Indonesia through eastern Myanmar and Peninsular Malaysia. They are mostly ilmenite-series calcalkaline biotite or hornblende-biotite granites. REE contents of the granites range from 60 to 600 ppm and they are relatively high in Peninsula Thailand. REE-bearing minerals consist mainly of apatite, zircon, allanite, titanite, monazite and xenotime. Some I-type granites contain REE fluorocarbonate (probably synchysite-(Ce)) in cavities and cracks in feldspars and it is the dominant source of REE for ion-adsorption ores because the fluorocarbonate is easily soluble during weathering. In contrast, insoluble monazite and xenotime are not preferable for ion-adsorption ores although they are common ore minerals of placer REE deposits. Weathered granites show REE contents ranging from 60 to 1100 ppm in Thailand because REE are relatively immobile compared with mobile elements (e.g., Na, K, Ca). In the weathered granites, REE are contained in residual minerals and secondary minerals and are adsorbed onto the surface of weathering products. A weathering profile of granite with ion-adsorption type mineralization can be divided into upper and lower parts based on REE enrichment and Ce

  18. PREDICTION OF LOCATION OF HIDDEN ORE DEPOSITS IN THE AGED ORE FIELDS:AN EXAMPLE FROM FENGHUANGSHAN ORE FIELD,TONGLING,CHINA

    Institute of Scientific and Technical Information of China (English)

    LIU; Liang-ming; PENG; Sheng-lin; YIANG; Qun-zhou; SHAO; Yong-jun; WANG; Zhi-qiang

    2001-01-01

    This paper discusses the strategy for successfully predicting the location of potential hidden ore bodies in aged ore field,and presents the result of location prediction of hidden ore bodies in Fenghuangshan ore field,Tongling.Innovative conceptual targeting procedures based on a genetic understanding of mineralization systems,carefully geological investigation and correct deduction,together with new geochemical and geophysical technology and integrating of comprehensive information are all very important for the successful prediction.In the aged Fenghuangshan ore field,through researching by application of the metallogenic theory of polygenetic compound ore deposits and triple-frequency induced polarization method and exploration tectono-geochemical method,we predicted location and quality of hidden ore bodies.According to the prediction,hidden high quality Cu-Au ore bodies of skarn type and porphyry type have been discovered.

  19. Main types of gold ore forming systems and their relationship with the paleogeodynamic settings on the Taimyr Peninsula and the Severnaya Zemlya Archipelago

    Science.gov (United States)

    Proskurnin, Vasiliy; Anatoly, Gavrish; Aleksandra, Bagaeva; Petrushkov, Boris; Shneider, Alexey; Saltanov, Vasily; Stepunina, Maria; Proskurnina, Alina

    2014-05-01

    Within the Taimyr - Severnaya Zemlya mineragenic province, the Late Paleozoic - Early Mesozoic Kara rare-metal - gold and Byrrangsky coal-bearing - polymetallic mineragenic areas are distinguished. Main geological commercial types of the Kara mineragenic area include manifestations of gold-quartz, gold sulphide-quartz (proper gold ore), and gold-rare metal, gold-bearing copper-molybdenum-porphyry formations. The Riphean - Vendian subduction - collisional and Late Paleozoic - Early Mesozoic repeated collisional (deuterogenic) ore-forming systems play a leading role in their formation. Regardless of the age and formation features, manifestations of proper gold ore formations are controlled by a common factor, the degree of metamorphism of host rocks - not above the sericite-biotite subfacies of the greenschist facies, and belong to the group of hydrothermal-metasomatic ore forming systems conditioned by alkali-acid differentiation of matter in temperature gradient field with ore concentration in mesozone. Depending on the host Precambrian formations, Kara Late Paleozoic - Early Mesozoic mineragenic area is subdivided into Mininsky-Bolshevistsky flysch-terrigenous carbonaceous zone with manifestation of zonal regional metamorphism of the andalusite-sillimanite type (Arctida passive margin) and Shrenk-Faddey volcanogenic-carbonate-terrigenous carbonaceous zone with ophiolites (accretion prism of Siberia). For the Riphean - Early Vendian endogenous manifestations, the following main types of gold ore forming systems are distinguished: in the passive marginal Mininsky-Bolshevistsky zone - early collisional metamorphic-hydrothermal in terrigenous carbonaceous complexes (Valterovsky, Voskresensky, Litkensky ore zones) and late collisional plutonic-hydrothermal in allochthonous granitoids of S-type (Martovsky-Nikitinsky ore cluster); in the accretionary Shrenck-Faddey zone - subduction-collisional plutonic-metamorphic-hydrothermal (Zhilninsky, Leningradsky ore zones) in

  20. Pelletized vs. natural iron ore technology: energy, labor, and capital changes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kakela, P.

    1978-09-01

    Total energy requirements per ton of iron-in-ore for natural and pelletized ore were calculated by a hybrid energy analysis. Energy requirements for ore preparation were subsequently considered as one energy input (embodied) to blast furnaces. Total energy requirements per ton molten iron were calculated for each year from 1955 through 1975 to identify changes attributable to the shift in iron ore preparation. Four results were found. (1) In practice, the lean ores are energetically superior. Pelletized ore requires more energy at the mine than natural ore, but pellets produce offsetting energy savings in the blast furnace. (2) Labor changes followed a similar pattern: man-hours per ton of molten iron increased at the mine with pelletization, but decreased at the blast furnance. Net labor required per ton of molten iron has decreased with pelletization. (3) Capital investments per ton of molten iron have increased greatly at iron ore mines with pelletization and decreased moderately at blast furnaces. New capital investment per ton of molten iron has increased with pelletization. (4) In the iron and steel industry, relatively low-priced energy held a substantial advantage over high-priced labor between 1950 and 1969. The industry, however, discovered that capital investments in pellet plants could save both labor and energy up to 1963; after 1963 capital and energy weresubstituted for labor. A sharp reversal of substitutional advantage occurred in 1970; energy jumped to the most costly factor. Thus capital presently shows a strong substitutional advantage over high-priced energy and intermediately-priced labor.

  1. Correlations among factors of sulfide ores in oxidation process at ambient temperature

    Institute of Scientific and Technical Information of China (English)

    吴超; 李孜军; 周勃

    2004-01-01

    Spontaneous combustion is one of the serious problems in the mining of sulfide ore deposits. The relevant factors, e. G. Oxygen absorption quantity, mass increase, contents of water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process were investigated both in theory and experiment. The results from the investigation show that there is no general interpretation relation among the oxygen absorption quantity, the contents of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature.However, there is a linear relationship between the mass increase of the sulfide ore samples in the oxidation process at ambient temperature and the quantity of oxygen absorption. Therefore, the simple and cheap mass scaling method is suitable for predicting the oxygen absorption performance of sulfide ores at ambient temperature in place of the expensive and complicated chemical method used hitherto. Furthermore, combined with other items of breeding-fire test, the mass increase potential can also be used to predict the spontaneous combustion tendency of sulfide ores.

  2. REE Mineralization in Kiruna-type Magnetite-Apatite Ore Deposits: Magmatism and Metasomatism

    Science.gov (United States)

    Harlov, D. E.

    2015-12-01

    Magnetite-apatite ore bodies of the Kiruna type occur worldwide and are generally associated with volcanic rocks or volcanism. They also show strong evidence of extensive metasomatism over a wide P-T range. Notable examples include the Kiirunavaara ore body, northern Sweden (Harlov et al., 2002, Chem. Geol., 191, 47-72); the Grängesberg ore body, central Sweden (Jonsson et al., 2010, NGF abstracts, vol 1, 88-89); the Mineville ore body, Adirondacks, New York, USA (McKeown and Klemc, 1956, U.S. Geol Sur Bull (1956), pp. 9-23); the Pea Ridge ore body, SE Missouri, USA (Kerr, 1998, MS Thesis, Univ. Windsor, Windsor, Ontario, Canada 113 pp); the Jurassic Marcona ore body in south-central Peru (Chen et al., 2010, Econ Geol, 105, 1441-1456); and a collection of ore bodies from the Bafq Region, central Iran (Daliran et al., 2010, Geol. Assoc. Canada, Short Course Notes, v. 20, p.147-159). In these ore bodies, low Th and U monazite, xenotime, allanite, REE carbonates, and/or REE fluorides are commonly associated with the apatite as inclusions, rim grains, or as independent grains in the surrounding mineral matrix. High contrast BSE imaging, coupled with EMPA and LA-ICPMS, indicates that the apatite has experienced fluid-induced alteration in the form of (Y+REE) + Na + Si + Cl depletion implying that it served as the source for the (Y+REE) (e.g. Kiirunavaara, northern Sweden; Harlov et al., 2002). Formation of monazite and xenotime associated with fluorapatite, as inclusions or rim grains, has experimentally been demonstrated to originate from the fluorapatite as the result of fluid-aided, coupled dissolution-reprecipitation processes (Harlov et al., 2005, Contrib. Mineral. Petrol. 150, 268-286). This is explains the low Th and U content of the monazite and xenotime. Fluid sources could range from 700-900 °C, residual, acidic (HCl, H2HSO4) grain boundary fluids, remaining after the last stages of ore body crystallization, to later stage, cooler (< 600 °C) (H2O-CO2-(Na

  3. SEVENTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W.

    2012-08-30

    surveillance (24% average). For GLT O-rings, separate service life estimates have been made based on the O-ring fixture leak test data and based on compression stress relaxation (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350 – 400 ºF). However, at 300 ºF, the room temperature leak test failures to date experienced longer aging times than predicted by the CSRbased model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 ºF will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining PCV O-ring fixtures.

  4. Cosmological nonlinear structure formation in full general relativity

    CERN Document Server

    Torres, Jose M; Diez-Tejedor, Alberto; Nunez, Dario

    2014-01-01

    We perform numerical evolutions of cosmological scenarios using a standard general relativistic code in spherical symmetry. We concentrate on two different situations: initial matter distributions that are homogeneous and isotropic, and perturbations to those that respect the spherical symmetry. As matter models we consider the case of a pressureless perfect fluid, i.e. dust, and the case of a real massive scalar field oscillating around the minimum of the potential. Both types of matter have been considered as possible dark matter candidates in the cosmology literature, dust being closely related to the standard cold dark matter paradigm. We confirm that in the linear regime the perturbations associated with these types of matter grow in essentially the same way, the main difference being that in the case of a scalar field the dynamics introduce a cut-off in the power spectrum of the density perturbations at scales comparable with the Compton wavelength of the field. We also follow the evolutions well beyond...

  5. Petrography and geochemistry of the primary ore zone of the Kenticha rare metal granite-pegmatite field, Adola Belt, Southern Ethiopia: Implications for ore genesis and tectonic setting

    Science.gov (United States)

    Mohammedyasin, Mohammed Seid; Desta, Zerihun; Getaneh, Worash

    2017-10-01

    The aim of this work is to evaluate the genesis and tectonic setting of the Kenticha rare metal granite-pegmatite deposit using petrography and whole-rock geochemical analysis. The samples were analysed for major elements, and trace and rare earth elements by ICP-AES and ICP-MS, respectively. The Kenticha rare metal granite-pegmatite deposit is controlled by the N-S deep-seated normal fault that allow the emplacement of the granite-pegmatite in the study area. Six main mineral assemblages have been identified: (a) alaskitic granite (quartz + microcline + albite with subordinate muscovite), (b) aplitic layer (quartz + albite), (c) muscovite-quartz-microcline-albite pegmatite, (d) spodumene-microcline-albite pegmatite, partly albitized or greisenized, (e) microcline-albite-green and pink spodumene pegmatite with quartz-microcline block, which is partly albitized and greisenized, and (f) quartz core. This mineralogical zonation is also accompanied by variation in Ta ore concentration and trace and rare earth elements content. The Kenticha granite-pegmatite is strongly differentiated with high SiO2 (72-84 wt %) and enriched with Rb (∼689 ppm), Be (∼196 ppm), Nb (∼129 ppm), Ta (∼92 ppm) and Cs (∼150 ppm) and depleted in Ba and Sr. The rare earth element (REE) patterns of the primary ore zone (below 60 m depth) shows moderate enrichment in light REE ((La/Yb)N = ∼8, and LREE/HREE = ∼9.96) and negative Eu-anomaly (Eu/Eu* = ∼0.4). The whole-rock geochemical data display the Within Plate Granite (WPG) and syn-Collisional Granite (syn-COLG) suites and interpret as its formation is crustal related melting. The mineralogical assemblage, tectonic setting and geochemical signatures implies that the Kenticha rare metal bearing granite pegmatite is formed by partial melting of metasedimentary rocks during post-Gondwana assembly and further tantalite enrichment through later hydrothermal-metasomatic processes.

  6. Re-Os (ICP-MS) dating of the massive sulfide ores from the Jinchuan Ni-Cu-PGE deposit

    Institute of Scientific and Technical Information of China (English)

    YANG Gang; DU Andao; LU Jiren; QU Wenjun; CHEN Jiangfeng

    2005-01-01

    Massive sulfide ore from the Jinchuan Ni-Cu-PGE deposit was dated by Re-Os technique using Carius Tube digestion, Os distillation, Re extraction by acetone and ICP-MS measurement. An isochron giving an age of 833 ± 35 Ma, initial 187Os/188Os ratio of 0.279 ± 0.018 (MSWD = 1.7) and γOs = 130 ± 15 is obtained. The Re-Os age obtained agrees, within analytical uncertainties, with previous SHRIMP zircon U-Pb age of 827 ± 8 Ma (n=5, MSWD = 4.3). The result suggests that the deposit was formed at Neoproterozoic and that the formation of the Jinchuan Ni-Cu-PGE sulfide deposit may be closely related to the plume activity, which were attributed to the breakup of the Rodinia supercontinent. The high γOs of the massive ores suggests that crustal material was involved in the formation of the Jinchuan deposit, however, the quantity of the added crustal material is less than 10%.

  7. Mobility factors of cracked ore in vibrating-ore draw shafts

    Institute of Scientific and Technical Information of China (English)

    WU Ai-xiang; JIANG Li-chun; CHEN Jia-sheng

    2005-01-01

    The mobile factors of cracked ore in vibrating-ore draw shafts were analyzed. The results show that the mobile coefficient of cracked ores will be mainly influenced by the combination of ore physical factors if the structure dimension and parameters of vibrating ore-draw shafts are sure. It decreases with increasing the cohesion, lump content, lump size and powder content and increases with increasing the porosity. The coefficient decreases with increasing the moisture content, but increases after the moisture content reaches a certain value. Uniform grain leads to better mobility, non-uniform grain leads to worse mobility. The value of the mobile coefficient should be in a range of 0.31.1 when designing the vibrating ore-draw shafts. According to correlation degree of grey system theory, the effects of factors on the mobility of cracked ore are given in the weight decreasing consequence as follows: moisture content, lump content, distribution of grain size, lump size, porosity, cohesion and powder ore content. It is unreasonable to neglect any one because the values of their weights are not obvious.

  8. On the problems of the Litija ore field

    Directory of Open Access Journals (Sweden)

    Ivan Mlakar

    1994-12-01

    Full Text Available All available information on the now inaccessible Pb-Zb-Ba deposits Litija, Zavrstnik, Zagorica, Maljek, Hrastarija and Štriglovec was critically evaluated. Data were completed and numerous earlier unsolved questions were answered.In the studied area the existence of a Middle Triassic tectonic-erosional phase was proved, the Old Tertiary overthrust structure analyzed and the relative ages of various neotectonic fault systems established.Special attention was attributed to the Litija, or Sitarjevec, deposit. On the ground of data on position of thick shale intercalations within Carboniferous sandstone the geological structure of the deposit was reconstructed, proofs on the conforming or unconforming position of orebodies collected, and certain relati¬onships between the pre-ore and post-ore tectonics clarified. With geochemical investigations the presence of an extensive dispersion halo was proved, in which the anomalies produced by Pb, Hg and Ba are the best expressed.Also the position of other deposits in space and in stratigraphic column was defined. At the end also the author's views on genesis and age of mineralization are presented. Orebodies are hydrothermal. subvertical, epignetic and predominantly discordant, with poorly expressed vertical zoning.The work is a synthesis of understanding of geological structure and mineralization in the Litija ore field.

  9. Structure-geochemical zoning of Topolninsk gold-ore field (Gorny Altai)

    Science.gov (United States)

    Timkin, T. V.; Lavrov, D. S.; Askanakova, O. Y.; Korotchenko, T. V.

    2014-08-01

    Geochemical zoning of prospective mineable gold-bearing skarns was carried out. The geochemical field abnormal structures of different hierarchy levels associated with gold- skarn formations were revealed. The interrelation between the structure of ore-geochemical fields and associated ring structures was studied. Complex structure-geochemical criteria for gold mineralization prospecting and evaluation were proposed.

  10. Formation of algae growth constitutive relations for improved algae modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Gharagozloo, Patricia E.; Drewry, Jessica Louise.

    2013-01-01

    This SAND report summarizes research conducted as a part of a two year Laboratory Directed Research and Development (LDRD) project to improve our abilities to model algal cultivation. Algae-based biofuels have generated much excitement due to their potentially large oil yield from relatively small land use and without interfering with the food or water supply. Algae mitigate atmospheric CO2 through metabolism. Efficient production of algal biofuels could reduce dependence on foreign oil by providing a domestic renewable energy source. Important factors controlling algal productivity include temperature, nutrient concentrations, salinity, pH, and the light-to-biomass conversion rate. Computational models allow for inexpensive predictions of algae growth kinetics in these non-ideal conditions for various bioreactor sizes and geometries without the need for multiple expensive measurement setups. However, these models need to be calibrated for each algal strain. In this work, we conduct a parametric study of key marine algae strains and apply the findings to a computational model.

  11. The $L - \\sigma$ relation for massive bursts of star formation

    CERN Document Server

    Chávez, Ricardo; Terlevich, Elena; Bresolin, Fabio; Melnick, Jorge; Plionis, Manolis; Basilakos, Spyros

    2014-01-01

    The validity of the emission line luminosity vs. ionised gas velocity dispersion ($L - \\sigma$) correlation for HII galaxies (HIIGx), and its potential as an accurate distance estimator are assessed. For a sample of 128 local ($0.02\\lesssim z\\lesssim 0.2$) compact HIIGx with high equivalent widths of their Balmer emission lines we obtained ionised gas velocity dispersion from high S/N high-dispersion spectroscopy (Subaru-HDS and ESO VLT-UVES) and integrated H$\\beta$ fluxes from low dispersion wide aperture spectrophotometry. We find that the $L - \\sigma$ relation is strong and stable against restrictions in the sample (mostly based on the emission line profiles). The `gaussianity' of the profile is important for reducing the rms uncertainty of the distance indicator, but at the expense of substantially reducing the sample. By fitting other physical parameters into the correlation we are able to significantly decrease the scatter without reducing the sample. The size of the starforming region is an important s...

  12. Study on rich iron ore for martin steel and the by-products of Cu and Co in Zhangjiawa iron deposit of Shandong province%山东莱芜张家洼铁矿平炉富矿和伴生的铜、钴组分研究

    Institute of Scientific and Technical Information of China (English)

    宗信德; 李卫; 王建; 乔伟; 张俊峰; 刘纪涛

    2012-01-01

    Zhangjiawa iron deposit is located at the plunge of Kuangshan arc anticline with proven rich I-ron ore resources of 7 060 X 104 t for martin steel making and by-product Cu 217 256. 1 t and Co 48 548. 3 t. According to the general occurrence of the rich iron ore and the by-products at the disconformity and structural superimpositions and tremendous high iron (copper) and sulfur contents of ore deposits (bodies) occrring in Benxi formation we consider that the ore materials are related to the high background values of Fe,Cu,Co of Shanxi style iron ore and Fe-Al shale of Benxi formation in Yuemengou group. Shanxi style iron ore and Fe-Al shale were in situ reworked and superimposed by hydrothermal fluid to form composite ore bodies at or near the disconformity and local rich iron ore for martin steel making and the by-product resources, or strutures channeled the hydrothermal fluid and transport the ore materials into contact zones and the wall rocks leading to bi-replacement filtration and formation of composite ore bodies at contact zone or nearby and small volume of rich iron ore for martin steel making and the by-products resources. Therefore, Shanxi style iron ore and Fe-Al shale are the main source for the rich iron ore for martin steel making and the by-products of Cu, Co.%山东莱芜张家洼铁矿赋存于矿山弧形背斜倾没端,已查明平炉富矿资源储量7 060×104t,伴生组分铜金属资源储量217 256.1 t,钴金属资源储量48 548.3 t.根据平炉富矿、伴生组分铜钴主要分布在假整合面及其复合部位,以及赋存在本溪组中的矿床(体)铁(铜)硫特高的特点,认为矿质与月门沟群本溪组中的山西式铁矿以及铁铝页岩层位中Fe,Cu,Co元素的高背景值有关.山西式铁矿和铁铝页岩层位或因热液作用就地改造叠加,在假整合面及附近形成复合矿体,并局部构成平炉富矿和伴生的铜、钻资源;或因构造沟通,被活化迁移至接触带与围岩中,产生

  13. Mineralogy and ore fluid chemistry of the Roc Blanc Ag deposit, Jebilet Hercynian massif, Morocco

    Science.gov (United States)

    Essarraj, Samira; Boiron, Marie-Christine; Cathelineau, Michel; Tarantola, Alexandre; Leisen, Mathieu; Hibti, Mohamed

    2017-03-01

    forming model proposed for the Roc Blanc deposit is: (i) the penetration of sedimentary brines coming from the adjacent basins into the basement (i.e. Hercynian formations), where they extracted Ag probably from abundant mafic rocks; ii) the ore deposition in structural traps below the post Hercynian unconformity thanks to brine mixing with low salinity fluids. The fluid circulation probably is related to the Atlasic rifting coeval with the Atlantic Triassic opening. Such a model contrasts with the previous one relating the Roc Blanc to the Hercynian granitic intrusions in the Jebilet. Ag deposition occurred during reworking of the early structures associated with the Hercynian orogenic events and metamorphic fluid circulation which led to the early Fe-As uneconomic stages forming the main N-S quartz veins. Similarities between The Roc Blanc Ag deposit and the major Ag deposits from Anti-Atlas south of Morocco strongly suggest that they resulted from a unique and large fluid circulation event and a major period of metal deposition.

  14. A study on the genetic relations between Permian Longtan Formation coal series strata and Carlin-type gold deposits, southwestern Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    NIE Aiguo; MEI Shiquan; GUAN Daiyun; WU Pan; ZHANG Zhuru

    2008-01-01

    A large number of the Carlin-type gold deposits occur in the Longtan Formation in southwestern Guizhou Province. The Longtan Formation contains abundant basalt, tuff and siliceous rocks. All rocks of the Longtan Formation are enriched in gold, which were deposited in a limited platform environment in the transition zone from marine to continental. The process of sedimentation was accompanied by the eruption of Emeishan basalt and hydrothermal deposition controlled by co-sedimentary submarine deep faults in the west, which led to the formation of a peculiar gold-bearing formation with coal series strata. This formation controlled the occurrence of the Carlin-type gold deposits in southwestern Guizhou Province. In response to the remobilization of the Emei mantle plume during the Yanshanian period, As, Au and other ore-forming materials were continuously extracted by deeply circulating waters from the Emeishan basalt and coal seams, thereafter forming ore-forming hydrothermal solutions.When these elements were transported in the coal seams, large amounts of As, Au and other elements were enriched in pyrite within the coal seams, thus forming high-As coal and Carlin-type gold deposits in the Longtan Formation coal series strata.

  15. Geochemical Behaviors of REE and Other Trace Elements during the Formation of Strata-bound Skarns and Related Deposits:A Case Study of the Dongguashan Cu(Au) Deposit,Anhui Province,China

    Institute of Scientific and Technical Information of China (English)

    LING Qicong; LIU Congqiang

    2003-01-01

    REE and other trace elements in the altered marbles, massive skarns and ores, as well as garnet and quartz were determined in order to examine the behaviors of trace elements during hydrothermal alteration. It is demonstrated that the high-field-strength (HFS) elements Zr, Hf, Th and Nb were immobile while other trace elements were mobile during the formation of skarns and related deposits. REE and ore-forming elements such as Cu and Ag in hydrothermally-altered marbles and skarns were provided primarily by hydrothermal fluids. In the direction transverse of the strata, the more deeply the marbles were altered, the higher the total REE abundance and the larger the negative Eu anomalies would be. The chondrite-normalized REE patterns of skarns are similar to those of the marbles, but the former are distinguished by much higher REE contents and more remarkable negative Eu anomalies. Those patterns were apparently not inherited from the marble protolith, but were controlled by garnets, which were determined by the hydrothermal solutions involved in the infiltration metasomatism. The hydrothermal fluids are characterized by having slightly right-hand dipping REE patterns, being enriched in LREE and having strongly negative Eu anomalies. The uptake of REE from hydrothermal fluids during the growth of garnet crystals resulted in the garnets having similar REE patterns to the hydrothermal fluids. Based on the spatial variation of REE in skarns and the structures of the hosting strata, we can get a better understanding of the transport path and pattern of the fluids involved in the formation of skarns and their related deposits. REE geochemistry investigation can help elucidate the genesis of skarns and skarn-related deposits.

  16. Selective Flocculation of Dilband Iron Ore, Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad Ishaque Abro

    2011-04-01

    Full Text Available Selective flocculation for long is known as one of the beneficiation techniques applicable to the concentration of finely disseminated ores. The success of this technique is based on the selective adsorption of an organic polymer on the mineral particles to be flocculated. In present study beneficiation of finely disseminated Dilband iron ore using selective flocculation has been attempted. The effect of pH, sodium silicate (Na2SiO3, sodium hexametaphosphate (Na2OP2O5, sodium trypolyphosphate (Na5P3O10, ethylediaminetretracetae (NaCH2-CH2N, flocculant doses, and flocculant mixing method on the selective adsorption of corn starch on hematite, the chief iron mineral, was studied comprehensively. Improvement in grade was assessed by XRF analysis of the flocculation products. The selective flocculation upgraded the ore from 52% hematite (i.e. 39% Fe to 60% hematite (i.e. 45% Fe with an average hematite recovery of 15%. Appreciable increase in ore grade with sufficiently poor recovery suggested that selective flocculation process is not adequate beneficiating technique to upgrade the Dilband iron ore due to heavily intergrowth of impurities.

  17. Geology and ore deposits of the Pioche district, Nevada

    Science.gov (United States)

    Westgate, L.G.; Knopf, Adolph

    1932-01-01

    LOCATION AND SURFACE FEATURES The Bristol Range, Highland, and Ely Range quadrangles make up the larger part of a. rectangular area 35 miles north and south by 24 miles east and west, which lies 19 miles west of the Nevada-Utah line and about 250 miles southwest of Salt Lake City. The district lies within the Great Basin, a semiarid region of alternating mountain ranges and intermontane plains floored largely by outwash from the mountains. The plain, which slopes away from the ranges, stands between 4,700 and 6,000 feet above the sea. The Bristol and Highland Ranges, which are separated only by a low gap, form an almost continuous north-south range that rises about 2,500 feet above the highest part of the surrounding plain, to general altitudes of 8,000 to 9,000 feet, though the highest point, Highland Peak, reaches 9,395 feet. A lower range, the Ely Range, with a northwesterly trend, lies farther east and nearly in touch with the Bristol-Highland Range. The town of Pioche lies midway on the. eastern foot of the Ely Range. ROOKS OF THE PIOOHB REGION The rocks of the ranges are Paleozoic sediments, Tertiary (?) lavas and intrusive rocks, and Pliocene (?) tuffs. The Paleozoic sediments have a total thickness of nearly 18,000 feet. Over 8,000 feet of the Cambrian has been measured without reaching its base. The lowest Cambrian formation is a quartzite, of which only the upper 1,500 feet is exposed, and this is followed by 1,200 feet of shale, 400 feet of limestone, aoid 150 feet of shale. Above this second shale the upper three-fourths of the Cambrian consists of limestone and dolomitic limestone. It is in the quartzite and in the limestone interbedded in and bounding the shales that the main ore bodies of the district have been found. Above the Cambrian comes 1,795 feet of Ordovician limestone, with some interbedded dolomite and with a 50-foot quartzite a, third of the way down from the top; 75 feet of Silurian dolomite; 3,000 feet of Middle Devonian dolomite with

  18. How Is Formative Assessment Related to Students' Reading Achievement? Findings from PISA 2009

    Science.gov (United States)

    Li, Hongli

    2016-01-01

    Drawing on the programme for international student assessment 2009 US data-set, this study examines the relationship between formative assessment and students' reading achievement using a structural equation modelling approach. We find that formative assessment is positively related to students' reading achievement directly and indirectly (through…

  19. The Radio Continuum-Star Formation Rate Relation in WSRT SINGS Galaxies

    NARCIS (Netherlands)

    Heesen, Volker; Brinks, Elias; Leroy, Adam K.; Heald, George; Braun, Robert; Bigiel, Frank; Beck, Rainer

    We present a study of the spatially resolved radio continuum-star formation rate (RC-SFR) relation using state-of-the-art star formation tracers in a sample of 17 THINGS galaxies. We use SFR surface density (ΣSFR) maps created by a linear combination of GALEX far-UV (FUV) and Spitzer 24 μm maps. We

  20. The Radio Continuum-Star Formation Rate Relation in WSRT SINGS Galaxies

    NARCIS (Netherlands)

    Heesen, Volker; Brinks, Elias; Leroy, Adam K.; Heald, George; Braun, Robert; Bigiel, Frank; Beck, Rainer

    2014-01-01

    We present a study of the spatially resolved radio continuum-star formation rate (RC-SFR) relation using state-of-the-art star formation tracers in a sample of 17 THINGS galaxies. We use SFR surface density (ΣSFR) maps created by a linear combination of GALEX far-UV (FUV) and Spitzer 24 μm maps. We

  1. Rare Earth Element Geochemistry on Magmatic Rocks and Gold Deposits in Shizishan Ore-Field of Tongling, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    REE geochemical characteristics of the magmatic rocks and gold deposits in Shizishan ore-field of Tongling were studied. Three types of the magmatic rocks have almost the same chondrite-normalized REE patterns, Eu and Ce anomalous values, and ΣREE, ΣLREE/ΣHREE regular changes, which indicates that their magmas come from the same source and their digenetic mechanism is fractional crystallization. In three gold deposits, the mineral ores and related altered rocks have similar chondrite-normalized REE patterns and sharp Eu positive anomalous values. The REE contents reduced from the magmatic rocks to skarnization or alteration magmatic rocks, skarn type ores, sulphide type ores, wall-rocks limestone or marble. The REE geochemical characteristics of the ores and related rocks show that primary fluids originated from magmatic differentiation in lower pressure of shallow crust, ore-forming hydrothermal solutions gained REE and mineralization elements further from leaching the magmatic rocks, then superimposed and reformed the limestones or marbles and deposited ore-forming material.

  2. Biofilm Formation in Staphylococcus Aureus and its Relation to Phenotypic and Genotypic Criteria

    Directory of Open Access Journals (Sweden)

    Hasannejad Bibalan, M. (MSc

    2014-09-01

    Full Text Available Background and Objective: Biofilm is a complex microbial community embedded in a self-produced extracellular polymeric matrix. We aimed to study the extent of biofilm formation by S. Areas isolates and its relation to some phenotypic and genotypic criteria. Material and Methods: One hundred-fifty strains of Staphylococcus aureus isolated from Gorgan were studied. Microtiter plate assay method was used for investigation of biofilm formation.The biofilm formation of strains were recorded and its relation to accessory gene regulator (agr and antibiotic resistance were assessed by X2 test. Results: Eighty-four isolates (56% were able to form biofilm. The strength of biofilm formation in agr group I was more than that of other groups. The biofilm formation among S. Areas isolated from the wound and urine (both with 75 % had the highest capability. Methicillin-resistant isolates had a greater ability to biofilm formation. Conclusion: Methicillin resistant isolates had a greater ability to biofilm formation. Given the importance and treatment related problems of Methicillin-Resistant Staphylococcus Aureus (MRSA especially Community Acquired-Methicillin-Resistant Staphylococcus Aureus (CA-MRSA, it is a necessity to control or remove the biofilm formation alongside antibiotic treatment.

  3. Studies on formation, control and application of biofilm formed by food related microorganisms.

    Science.gov (United States)

    Furukawa, Soichi

    2015-01-01

    Biofilms are sessile microbial aggregates on the interfaces, and they were usually considered as microbial contamination sources in medical care and various industries. We studied the control and application of biofilms formed by food-related microorganisms, and mechanism of the biofilm formation was also investigated. We studied the biofilm formation in mixed cultures using various combinations of two strains of food-related microorganisms. There were various microorganisms that showed decreased or increased biofilm formation in the mixed culture in comparison with that in a single culture. Biofilm formed by lactic acid bacteria and yeast isolated from traditional fermented food, Fukuyama pot vinegar, exhibited unique feature in that structure and formation mechanism, and expected to be used as an immobilized microorganism in fermentation production. Here our studies on the control and application of biofilms and the mechanisms of its formation were described.

  4. Ultrafine particles derived from mineral processing: A case study of the Pb-Zn sulfide ore with emphasis on lead-bearing colloids.

    Science.gov (United States)

    Mikhlin, Yuri; Vorobyev, Sergey; Romanchenko, Alexander; Karasev, Sergey; Karacharov, Anton; Zharkov, Sergey

    2016-03-01

    Although mining and mineral processing industry is a vast source of heavy metal pollutants, the formation and behavior of micrometer- and nanometer-sized particles and their aqueous colloids entered the environment from the technological media has received insufficient attention to date. Here, the yield and characteristics of ultrafine mineral entities produced by routine grinding of the Pb-Zn sulfide ore (Gorevskoe ore deposit, Russia) were studied using laser diffraction analysis (LDA), dynamic light scattering (DLS) and zeta potential measurement, microscopy, X-ray photoelectron spectroscopy, with most attention given to toxic lead species. It was revealed, in particular, that the fraction of particles less that 1 μm in the ground ore typical reaches 0.4 vol. %. The aquatic particles in supernatants were micrometer size aggregates with increased content of zinc, sulfur, calcium as compared with the bulk ore concentrations. The hydrodynamic diameter of the colloidal species decreased with time, with their zeta potentials remaining about -12 mV. The colloids produced from galena were composed of 20-50 nm PbS nanoparticles associated with lead sulfate and thiosulfate, while the surface oxidation products at precipitated galena were largely lead oxyhydroxides. The size and zeta potential of the lead-bearing colloids decreased with time down to about 100 nm and from -15 mV to -30 mV, respectively. And, conversely, lead sulfide nanoparticles were mobilized before the aggregates during redispersion of the precipitates in fresh portions of water. The potential environmental impact of the metal-bearing colloids, which is due to the large-scale production and relative stability, is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Minerogenic System of Magnesian Nonmetallic Deposits in Early Proterozoic Mg-rich Carbonate Formations in Eastern Liaoning Province

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the early Proterozoic the Liryu Formation and Dashiqiao Formation of eastern Liaoning province, China, there are distributed Mg-rich carbonate rock formations, in which large to superlarge deposits of boron, magnesite, talc, Xiuyan jade etc. occur. The formation of these magnesian nonmetallic deposits was related to early Proterozoic evaporates; then these deposits underwent reworking of regional metamorphism and hydrothermal metasomatism during the Lüliang orogeny and tectono-magmatism during the Indosinian-Yanshanian. Among other things, the Mg-rich carbonates formations, minerogenetic structures and ore-forming fluids played a controlling role in the formation of the mineral deposits. The refore, it can be concluded that the mineral deposits are products of combined processes of the coupling of ore source field, fluid field, thermal field (energy field) and stress field under certain time-space conditions in the early Proterozoic and the late-stage superimposed reworking of tectono-magmatism.

  6. A new radiation shielding material: Amethyst ore

    Energy Technology Data Exchange (ETDEWEB)

    Korkut, Turgay, E-mail: turgaykorkut@hotmail.co [Faculty of Science and Art, Department of Physics, Ibrahim Cecen University, Agri (Turkey); Korkut, Hatun [Faculty of Science and Art, Department of Physics, Ibrahim Cecen University, Agri (Turkey); Karabulut, Abdulhalik; Budak, Goekhan [Faculty of Science, Department of Physics, Atatuerk University, Erzurum (Turkey)

    2011-01-15

    This paper describes a new radiation shielding material, amethyst ore. We have determined the elemental composition of amethyst using WDXRF spectroscopy technique. To see the shielding capability of amethyst for several photon energies, these results have been used in simulation process by FLUKA Monte Carlo radiation transport code. Linear attenuation coefficients have been calculated according to the simulation results. Then, these values have been compared to a fine shielding concrete material. The results show that amethyst shields more gamma beams than concrete. This investigation is the first study about the radiation shielding properties of amethyst ore.

  7. METALLOGENIC SYSTEM OF DACHANG TINPOLYMETALLIC ORE FIELD

    Institute of Scientific and Technical Information of China (English)

    WU Xiang-bin; DAI Ta-gen; WANG Zhi-bin; FANG Sheng-kui

    2001-01-01

    The Dachang tin-polymetallic ore field in northern Guangxi,China,lies in a mid-late Paleozoic rift that borders up the southern boundary of the Jiangnan-Xuefeng Massif.As a giant ore deposit,it deposited in middle of the Nandang-Hechi metallogenic zone.The orehosting strata are of the Devonion,which shows the evident characteristics of polymetallic elements,i.e: ,Sn,Zn,Pb,Sb,As,Cu,Ag,In,Ge,Cd,et al.,and over 1 000 000 t tin reserves.

  8. Partitioning properties of rare earth ores in China

    Institute of Scientific and Technical Information of China (English)

    CHI Ru'an; LI Zhongjun; PENG Cui; ZHU Guocai; XU Shengming

    2005-01-01

    The properties of rare earth partitioning in Chinese industrial rare earth ores were analyzed. Rare earth ores can be divided into the single-mineral type ore with bastnaesite, the multi-mineral type ore with bastnaesite and monazite, and the weathering crust type. Both the Bayan Obo rare earth ore and the Zhushan rare earth ore are a kind of mixed ore, consisting of bastnaesite and monazite. Their rare earth partitionings are strongly enriched in light rare earths, where CeO2 is 50% and the light rare earth partitioning is totally over 95%. The Mianning rare earth ore as well as the Weishan rare earth is a kind of rare earth ore only having bastnaesite. Their rare earth partitionings are also strongly enriched in light rare earths,in which CeO2 is 47% and the light rare earth partitioning is totally over 94%. For the weathering crust type rare earth ore,there are the Longnan rare earth ore, the Xunwu rare earth ore, and the middle yttrium and rich europium ore. In the Longnan rare earth ore, which is strongly enriched in heavy rare earths, Y2O3 is 64.83%, and the heavy and light rare earth partitionings are 89.40% and 10.53%, respectively. In the Xunwu rare earth ore, which is strongly enriched in light rare earths, CeO2 is 47.16%, and the light rare earth partitioning is totally 93.25%. Y and Eu are enriched in the middle yttrium and rich europium ore. Its middle rare earth partitioning is totally over 10%, and Eu2O3 and Y2O3 are over 0.5% and 20%,respectively, which are mainly industrial resources of the middle and the heavy rare earths.

  9. Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland

    Science.gov (United States)

    Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.

    1996-01-01

    as indicated by the geologic evidence, the source rocks probably contained elevated concentrations of Zn and Pb (75-100 ppm), and relatively low concentrations of U and Th (2 and 8 ppm or less, respectively). The Carboniferous coal-bearing molasse rocks of the Upper Silesian Coal Basin are a prime candidate for such a source region. The presence of ammonia and acetate in the fluid inclusions (Viets et al., 1996a) also indicate that the Carboniferous coal-bearing molasse sequence in the Upper Silesian Coal Basin may have been a suitable pathway for the MVT ore fluids. The lead-isotopic homogeneity, when coupled with the sulfur-isotopic heterogeneity of the ores suggests that mixing of a single metal-bearing fluid with waters from separate aquifers containing variable sulfur-isotopic compositions in karsts in the Muschelkalk Formation of Middle Triassic age may have been responsible for the precipitation of the ores of the Silesian-Cracow district.

  10. Research on the Characteristics of Wall Rock Alteration and Ore Fabric of Shizishan Copper Deposit, Yimeng, Yunnan%云南易门狮子山铜矿床围岩蚀变岩相与矿石组构特征研究

    Institute of Scientific and Technical Information of China (English)

    吴雪山

    2013-01-01

    云南省易门狮子山铜矿床为昆阳裂谷典型的沉积-改造型铜矿床之一.矿床深部铜矿化与围岩蚀变有关,碳酸岩化与铜矿化关系密切.硅质白云岩类型铜矿体,矿石构造以脉状构造、浸染状构造为主;飘带矿矿石构造以层状构造为主.白云岩型铜矿中金属颗粒较细,为斑铜矿和黄铜矿;板岩型铜矿中金属颗粒较粗,为黄铜矿和黄铁矿.矿石化学成分具有高Si、Ca、Mg的特点,落雪组与鹅头厂组接触部位是重要的找矿地段.%Shizishan copper deposit,Yimeng,Yunnan is one of the typical sedimentary-reformed copper deposit in Kunyang rift valley.The Cu mineralization at the deep part of the deposit is relative to wall rock alteration,the carbonation has close relations with Cu mineralization.The ores in siliceous dolomite type copper ore body are mainly of vein structure,disseminated structure; the ribbon ore is mainly of layer structure.The mineral particle in dolomite type copper ore is finer,which is bornite and copper pyrites; the mineral particle in slate type copper ore is coarser,which is copper pyrites and pyrite.The chemical composition of ore has the features of high Si,Ca and Mg,the important prospecting area is the contact zone of Luoxue and Etouchang formations.

  11. Sintering Properties and Optimal Blending Schemes of Iron Ores

    Institute of Scientific and Technical Information of China (English)

    Dauter0liveira; WUSheng—li; DAIYu—ming; XUJian; CHEN Hong

    2012-01-01

    In order to obtain good sintering performance, it is important to understand sintering properties of iron ores. Sintering properties including chemical composition, granulation and high-temperature behaviors of ores from China, Brazil and Australia. Furthermore, several indices were defined to evaluate sintering properties of iron ores. The results show that: for chemical composition, Brazilian ores present high TFe, low SiOz, and low Alz03 con- tent. For granulation, particle diameter ratio of Brazilian ores are high; particle intermediate fraction of Chinese con- centrates are low; and average particle size and clay type index of Australian ores are high. For high-temperature properties, ores from China, Brazil and Australia present different characteristics. Ores from different origins should be mixed together to obtain good high-temperature properties. According to the analysis of each ore's sintering prop- erties, an ore blending scheme (Chinese concentrates 20 ~-1- Brazilian ores 400//oo -k Australian ores 40 ~) was sugges- ted. Moreover, sinter pot test using blending mix was performed, and the results indicated that the ore blending scheme led to good sintering performance and sinter quality.

  12. Assessment of the reduced ore cooling process at the Ernesto Che Guevara Plant

    Directory of Open Access Journals (Sweden)

    Ever Góngora-Leyva

    2012-10-01

    Full Text Available The analysis of the investigations related to evaluations on the process of reduced ore cooling in rotating horizontal cylinders on an industrial scale indicated that there are only water temperature measurements on one end of pit and showed no experiments where the variables of water and ore flowrates were evaluated nor the relation with the temperature of the ore at the cooler outlet. Based on this precedent, six thermocouples were installed to calculate the cooling water temperature in three locations on both sides of the pit connected to the data input system in place in the enterprise. The design of the experiment was developed from analyzing a population of data from a 6/month period. The results showed that the variable of greater impact on the ore temperature at the cot oler outlet is the water flowrate. For lower water flowrates (15m3/h heat transfer by water evaporation to the air is predominant and for higher water flowrates (25m3/h heat transfer by convection is predominant. Also, it was possible to know that the cooler heat output reaches the highest values (86% with the lowest ore and water flowrates (15m3/h and 29t/h, respectively.

  13. Novel applications of microwaves in the metallurgical processing of a nickel-ferrous laterite ore and an aluminum industry waste

    Science.gov (United States)

    Samouhos, M.; Taxiarchou, M.; Kouvelos, E.

    2016-04-01

    Microwave radiation is a relatively new source of energy in the pyrometallurgical process. In this study, the application of microwaves in the carbothermic reductive roasting of a nickeliferous hematitic laterite ore and a red mud are investigated. The effective microwave heating (at temperatures above 900°C) of the aforementioned materials is attainable due to the relatively high values of their imaginary permittivity (ε")- In both two cases, the reduction of the included hematite was attempted, and the reduction degree was calculated as a function of: (a) the heating time and (b) the supplied microwave power. The mechanism of Fe+3 to Fe0 conversion was investigated using Mössbaurer spectroscopy revealing the formation of magnetite, fayalite and nano-structured metallic iron. Finally, it should be noted that that the gaseous products of the microwave pyrometallurgical process were analyzed using a mass spectroscopic technique, which is an important novelty.

  14. SIXTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W.

    2011-08-31

    (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350-400 F). However, at 300 F, the room temperature leak test failures to date experienced longer aging times than predicted by the CSR-based model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 F will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining fixtures.

  15. Sandbox experiments on Uraninite Ore: ERT and SP measurments.

    Science.gov (United States)

    Singh, R. K.

    2015-12-01

    Nuclear energy, considering its own intrinsic merits, would be a leading source for meeting the energy requirement in present and future scenario. Concealed Uranium deposits under sedimentary cover, with poor surface indications calls for reorientation of survey with large inputs involving integrated geophysical approach. Sand Box experiments have been carried out over Uraninite ore. The tank is a glass fish tank (height 39 cm, length 75 cm, width 30 cm). It was filled with sand up to 35 cm high. The sand was saturated from below to minimize the entrapment of the gas bubbles. The average size for sand grains is ~ 0.295mm. The formation factor of the sand is 3.5, with a negligible surface conductivity because of the coarse nature of the sand grains. The dimension of considered Uraninite ore sample is 4cm x 4cm x 4cm. The depth of top of the ore sample is kept at 3cm. In this paper both resistivity and self-potential measurements were carried out for possible detection of Uraninite. The resistivity measurements were made with 64 non-polarizable electrodes using Electrical Resistivity Tomography (ERT) equipment of FlashRes Universal developed by ZZ Resistivity Imaging Pty. Ltd. We have used screws of length 3cm as electrodes. The separation between these electrodes are ~ 1cm. The resistivity tomography results clearly outlines the target Uraninite body. The resistivity tomography results also detects small heterogeneities associated with air bubbles possibly due to unsaturated pore spaces. SP measurements were made using two non-polarizing Pb/PbCl2 electrodes and a Fluke 289 voltmeter (sensitivity 0.001 mV, internal impedance 100 MOhm). The reference electrode was located on the corner of the sandbox. The other electrode was used to scan the electrical potential at the surface of the sand. SP measurements were made with a spacing of 3 cm over the same ERT profile. The SP results also shows a dip (or a low SP anomaly) over the target ore body sample. Thus, both SP and

  16. The Star Formation and AGN luminosity relation: Predictions from a semi-analytical model

    CERN Document Server

    Gutcke, Thales A; Maccio`, Andrea V; Lacey, Cedric

    2015-01-01

    In a Universe where AGN feedback regulates star formation in massive galaxies, a strong correlation between these two quantities is expected. If the gas causing star formation is also responsible for feeding the central black hole, then a positive correlation is expected. If powerful AGNs are responsible for the star formation quenching, then a negative correlation is expected. Observations so far have mainly found a mild correlation or no correlation at all (i.e. a flat relation between star formation rate (SFR) and AGN luminosity), raising questions about the whole paradigm of "AGN feedback". In this paper, we report the predictions of the GALFORM semi-analytical model, which has a very strong coupling between AGN activity and quenching of star formation. The predicted SFR-AGN luminosity correlation appears negative in the low AGN luminosity regime, where AGN feedback acts, but becomes strongly positive in the regime of the brightest AGN. Our predictions reproduce reasonably well recent observations by Rosa...

  17. Clay mineralogy of the Greenvale Ore Body, Queensland, Australia: Implications for the interpretation of paleoclimate

    Energy Technology Data Exchange (ETDEWEB)

    Lev, S.; Anderson, K.; Ramirez, B.; Sun, H.; Swank, R.; Yost, D.; Huff, W.; Maynard, J.B. (Univ. of Cincinnati, OH (United States). Dept. of Geology)

    1994-03-01

    A 3--5% nickel enriched laterite in the Greenvale Ore Body of Queensland, Australia, is the result of weathering a serpentinized ultramafic intrusion. Variations in solubilities and drainage, typical of laterite deposits, resulted in the formation of three primary zones: (1) the Saprolite zone, (2) the Intermediate zone, and (3) the Limonite zone. Within these zones, clay mineral species with distinct chemistries and/or mineralogies have been identified, including: Ni-rich Smectite, Halloysite, and Palygorskite. Clay minerals were analyzed using powder X-ray diffraction and SEM. Bulk chemistry was determined by X-ray fluorescence in an attempt to better constrain the chemical conditions at the time of formation of the clay minerals. Results indicate a complex drainage system and history for the Greenvale Ore Body. Based on the distribution of ore grade material, it is apparent that the deposit was initially characterized by fracture controlled drainage. Owing to precipitation of Ni-rich smectite, halloysite, and palygorskite, subsequent alteration of the ore body drainage network and/or local climate can be inferred.

  18. Geochemical Characteristics and Source of Ore-Forming Fluid of Duolanasayi Gold Deposit, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    肖惠良; 周济元; 王鹤年; 董永观; 季俊峰; 赵宇

    2003-01-01

    The Duolanasayi gold deposit, 60 km NW of Habahe County in Xinjiang, is a medi-um-large scale gold deposit controlled by the coupled ore-forming processes involving brittle-duc-tile shearing, albitite veins, and post-stage magma solution. Fluid inclusion studies indicate thatthe homogenization temperatures range from 160℃ to 315℃ with the peak values of 220 -300℃. Mineralization pressures are from 21.0 MPa to 64.5 MPa. Ore fluid inclusions containCa2+, K+, Na+, Mg2+; HCO3-, SO242-, HS-, F-, Cl- and Au+( maximum: 5.3 × 10-6),and the mineralizing fluid is a H2O-CO2 system. Sulfur, hydrogen, oxygen and strontium isotop-ic compositions ( δS = - 2.46‰ - - 7.02‰, δ 18 OH2O = 1.65‰ - 12.4‰, δD = - 132.2‰- -51.8‰, (Sr/Sr)i =0.7043 -0.7073) suggest that the ore-forming fluid is the mixture ofmagmatic water, meteoric water, metamorphic water and formation water sealed in rocks andstrata. It is mainly magmatic water in the early stage, and mixing fluid of water, meteoric water,metamorphic water and formation water that occurred in rocks and strata in the major mineraliza-tion stage. The ore-forming materials were derived from the upper mantle or lower crust.

  19. Analyzing the international exergy flow network of ferrous metal ores.

    Science.gov (United States)

    Qi, Hai; An, Haizhong; Hao, Xiaoqing; Zhong, Weiqiong; Zhang, Yanbing

    2014-01-01

    This paper employs an un-weighted and weighted exergy network to study the properties of ferrous metal ores in countries worldwide and their evolution from 2002 to 2012. We find that there are few countries controlling most of the ferrous metal ore exports in terms of exergy and that the entire exergy flow network is becoming more heterogeneous though the addition of new nodes. The increasing of the average clustering coefficient indicates that the formation of an international exergy flow system and regional integration is improving. When we contrast the average out strength of exergy and the average out strength of currency, we find both similarities and differences. Prices are affected largely by human factors; thus, the growth rate of the average out strength of currency has fluctuated acutely in the eleven years from 2002 to 2012. Exergy is defined as the maximum work that can be extracted from a system and can reflect the true cost in the world, and this parameter fluctuates much less. Performing an analysis based on the two aspects of exergy and currency, we find that the network is becoming uneven.

  20. Analyzing the International Exergy Flow Network of Ferrous Metal Ores

    Science.gov (United States)

    Qi, Hai; An, Haizhong; Hao, Xiaoqing; Zhong, Weiqiong; Zhang, Yanbing

    2014-01-01

    This paper employs an un-weighted and weighted exergy network to study the properties of ferrous metal ores in countries worldwide and their evolution from 2002 to 2012. We find that there are few countries controlling most of the ferrous metal ore exports in terms of exergy and that the entire exergy flow network is becoming more heterogeneous though the addition of new nodes. The increasing of the average clustering coefficient indicates that the formation of an international exergy flow system and regional integration is improving. When we contrast the average out strength of exergy and the average out strength of currency, we find both similarities and differences. Prices are affected largely by human factors; thus, the growth rate of the average out strength of currency has fluctuated acutely in the eleven years from 2002 to 2012. Exergy is defined as the maximum work that can be extracted from a system and can reflect the true cost in the world, and this parameter fluctuates much less. Performing an analysis based on the two aspects of exergy and currency, we find that the network is becoming uneven. PMID:25188407

  1. Actions of parathyroid hormone related peptide in mouse parietal endoderm formation

    NARCIS (Netherlands)

    Veltmaat, J.M.

    2001-01-01

    Summary Since about a decade, several reports have strongly suggested a role for parathyroid hormone related peptide (PTHrP) in the formation of parietal endoderm (PE) in the mouse embryo. This thesis is aimed first at elucidating the biological significance of parathyroid hormone related peptide

  2. Formats

    Directory of Open Access Journals (Sweden)

    Gehmann, Ulrich

    2012-03-01

    Full Text Available In the following, a new conceptual framework for investigating nowadays’ “technical” phenomena shall be introduced, that of formats. The thesis is that processes of formatting account for our recent conditions of life, and will do so in the very next future. It are processes whose foundations have been laid in modernity and which will further unfold for the time being. These processes are embedded in the format of the value chain, a circumstance making them resilient to change. In addition, they are resilient in themselves since forming interconnected systems of reciprocal causal circuits.Which leads to an overall situation that our entire “Lebenswelt” became formatted to an extent we don’t fully realize, even influencing our very percep-tion of it.

  3. Rare Earth Elements Geochemistry of Laowan Gold Deposit in Henan Province: Trace to Source of Ore-Forming Materials

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The compositions of REE in quartz and pyrite from the main stage of the Laowan gold deposit in Henan Province and that in quartz from Laowan granite were determined by inductively coupled plasma-mass-spectrometry (ICP-MS) to trace the source of ore-forming materials. Meanwhile, the REE compositions of the deposit ore, granite and metamorphic wall rock were also considered for comparative studies in detail. The range of ∑REE of quartz and pyrite from the deposit ores is 4.18×10-6~30.91×10-6, the average of ∑REE is 13.39×10-6, and the average of ∑REE of quartz in the Laowan granite is 6.68×10-6. There is no distinct difference of REE parameters between the deposit ore quartz and granite quartz. The quartz in gold deposit has the same REE particular parameters as quartzes from Laowan granite, such as δEu, δCe, (La/Yb)N and (La/Sm)N, partition degree of LREE to HREE, especially, the chondrite-normalized REE patterns, but no similarity to those from metamorphic wall rock, which shows that ore-forming hydrothermal fluid is mainly the fluid coming from the Laowan granite magma, rather than metamorphic fluid. Meanwhile, comparison studies on REE features between minerals from the deposit ores and related geological bodies in the deposit show that REE characteristics of minerals can serve as an indicator of ore-forming fluid properties and sources, while the REE characteristics of the bulk samples (such as deposit ores, granites and wall rocks) can not trace the source of the ore-forming materials exactly.

  4. Mining and processing of uranium ores at the Streltsovsky ore field

    Energy Technology Data Exchange (ETDEWEB)

    Ovseytchuk, V.A.; Litvinenko, V.G.; Kultishev, V.I. [Joint Stock Company, Priargunsky Industrial Mining and Chemical Union, Krasnokamensk, Chita Region (Russian Federation)

    2000-07-01

    The uranium deposits of Streltsovsky ore fields provide raw materials for Russian nuclear industry. For this region, it is important to achieve continued and increased activities in the recovery of mineral resources of uranium. Similarly, maintaining the mining and processing of uranium ores ensures the supply of raw materials for the nuclear industry. With the current operations, increasing the mining and processing activities would increase the cost of production of uranium oxides due to decreasing grades of ore body. After a review of the existing economic, technological and natural factors, a solution was proposed based on the joint application of underground mining and ore enrichment and processing with the help of hydrometallurgical process, in-situ leaching. Reduction of operation coasts and creation of radiation-safe working conditions could be achieved with the application of these systems involving concrete hardening in the mines and in-situ leaching of ore. With the help of economic-mathematical modeling, methods for rational application of various technologies could be determined and their processing parameters were specified. A reduction of coasts could be obtained and favorable conditions could be established for improvement in the treatment of lower grade ores by heap leaching. Application of purification of mine waters and tailing pond reduces the influence of the radiation and the impact on the natural environment. (author)

  5. Hydrogen Reduction of Hematite Ore Fines to Magnetite Ore Fines at Low Temperatures

    Directory of Open Access Journals (Sweden)

    Wenguang Du

    2017-01-01

    Full Text Available Surplus coke oven gases (COGs and low grade hematite ores are abundant in Shanxi, China. Our group proposes a new process that could simultaneously enrich CH4 from COG and produce separated magnetite from low grade hematite. In this work, low-temperature hydrogen reduction of hematite ore fines was performed in a fixed-bed reactor with a stirring apparatus, and a laboratory Davis magnetic tube was used for the magnetic separation of the resulting magnetite ore fines. The properties of the raw hematite ore, reduced products, and magnetic concentrate were analyzed and characterized by a chemical analysis method, X-ray diffraction, optical microscopy, and scanning electron microscopy. The experimental results indicated that, at temperatures lower than 400°C, the rate of reduction of the hematite ore fines was controlled by the interfacial reaction on the core surface. However, at temperatures higher than 450°C, the reaction was controlled by product layer diffusion. With increasing reduction temperature, the average utilization of hydrogen initially increased and tended to a constant value thereafter. The conversion of Fe2O3 in the hematite ore played an important role in the total iron recovery and grade of the concentrate. The grade of the concentrate decreased, whereas the total iron recovery increased with the increasing Fe2O3 conversion.

  6. Relation between thermal expansion and interstitial formation energy in pure Fe and Cr

    Energy Technology Data Exchange (ETDEWEB)

    Wallenius, Janne [Department of Nuclear and Reactor Physics, KTH, AlbaNova University Centre, Stockholm 10691 (Sweden) and Department of Neutron Research, Uppsala University, Uppsala (Sweden)]. E-mail: janne@neutron.kth.se; Olsson, Paer [Department of Neutron Research, Uppsala University, Uppsala (Sweden); Lagerstedt, Christina [Department of Nuclear and Reactor Physics, KTH, AlbaNova University Centre, Stockholm 10691 (Sweden)

    2005-01-01

    By fitting a potential of modified Finnis-Sinclair type to the thermal expansion of ferromagnetic Fe and paramagnetic Cr, stability of the <1 1 0> self-interstitial atom is obtained. The resulting potentials are relatively hard, yielding high SIA formation energies. Less hard potentials give lower interstitial formation energy, but predict too small thermal expansion. We also show that the formation energy of the <1 1 1> SIA depends on distances in-between the 2nd and 3rd neighbour. By raising the value of the pair potential in this region, the energy difference with respect to the <110> configuration calculated with VASP in the PAW approximation can be reproduced.

  7. Study on Metallized Reduction and Magnetic Separation of Iron from Fine Particles of High Iron Bauxite Ore

    Science.gov (United States)

    Liu, Zheng-Gen; Chu, Man-Sheng; Wang, Zheng; Zhao, Wei; Tang, Jue

    2017-01-01

    High iron bauxite ore is a typical unmanageable polyparagenetic resource and owns high comprehensive utilization value. Separation of iron from fine particles of high iron bauxite ore by the process of metallized reduction and magnetic dressing was researched systemically. The effect of magnetic field intensity, reduction temperature, reduction time, mole ratio of fixed carbon to reducible oxygen (FC/O) and ore particles size on separation indexes was researched. The results show that, with the conditions of reduction temperature of 1,400 °C, reduction time of 180 min, FC/O of 2.0, ore particle size of -2.0 mm and magnetic field intensity of 40 KA/m, about 89.24 % of the iron could be removed from high iron bauxite ore as metallic iron. Meanwhile, 86.09 % of the aluminum is stayed in non-magnetic fraction as alumina. However, the formation of hercynite (FeAl2O4) limits the reduction rate of iron oxides to metallic iron. The lower reduction conditions and higher recovery ratio of iron could be achieved with adopting ore-coal composite agglomerates or adding catalyst.

  8. Application of lead and strontium isotope ratio measurements for the origin assessment of uranium ore concentrates.

    Science.gov (United States)

    Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Keegan, Elizabeth; Millet, Sylvain

    2009-10-15

    Lead and strontium isotope ratios were used for the origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. A simple and low-background sample preparation method was developed for the simultaneous separation of the analytes followed by the measurement of the isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The lead isotopic composition of the ore concentrates suggests applicability for the verification of the source of the nuclear material and by the use of the radiogenic (207)Pb/(206)Pb ratio the age of the raw ore material can be calculated. However, during data interpretation, the relatively high variation of the lead isotopic composition within the mine site and the generally high contribution of natural lead as technological contamination have to be carefully taken into account. The (87)Sr/(86)Sr isotope ratio is less prone to the variation within one mine site and less affected by the production process, thus it was found to be a more purposeful indicator for the origin assessment and source verification than the lead. The lead and strontium isotope ratios measured and the methodology developed provide information on the initial raw uranium ore used, and thus they can be used for source attribution of the uranium ore concentrates.

  9. Contact angle of water on iron ore fines: Measurement and analysis

    Directory of Open Access Journals (Sweden)

    Huang X.B.

    2015-01-01

    Full Text Available The relative contact angle (θRCA for seven iron ore fines was measured by using Washburn Osmotic Pressure method under laboratory conditions. By choosing cyclohexane as the reference that can perfectly wet iron ore particles, the relative contact angles were measured and varied from 57° to 73°. With the volume % of goethite (φG as the variable, a new model for relative contact angle was developed. The expected relative contact angle for pure goethite is about 56°, while that for goethite free samples is about 77°. Physical properties, such as surface morphology (SMI and pore volume (Vpore can influence the relative contact angle. The φG can be expressed as a function of SMI and VPore. Thus, we inferred that the relative contact angle is a function of φG for the iron ores used. The measured relative contact angles were found to be in good agreement (Radj 2 >0.97 with the calculated ones based on the research from Iveson, et al. (2004. Comparing with the model developed by Iveson et al.(2004, the new model for contact angle proposed in this paper is similar, but more detailed with two meaningful physical parameters. The modification of physicochemical properties on iron ores would be another topic in the further study on granulation.

  10. High-rate behaviour of iron ore pellet

    Directory of Open Access Journals (Sweden)

    Gustafsson Gustaf

    2015-01-01

    Full Text Available Iron ore pellets are sintered, centimetre-sized spheres of ore with high iron content. Together with carbonized coal, iron ore pellets are used in the production of steel. In the transportation from the pelletizing plants to the customers, the iron ore pellets are exposed to different loading situations, resulting in degradation of strength and in some cases fragmentation. For future reliable numerical simulations of the handling and transportation of iron ore pellets, knowledge about their mechanical properties is needed. This paper describes the experimental work to investigate the dynamic mechanical properties of blast furnace iron ore pellets. To study the dynamic fracture of iron ore pellets a number of split Hopkinson pressure bar tests are carried out and analysed.

  11. The influence of relational formative discourse on students' positional identities in a middle school science classroom

    Science.gov (United States)

    Trauth-Nare, Amy

    Formative assessment is the process of eliciting students' understanding during instruction in order to make sensitive instructional decisions and provide feedback to enhance students' learning. Research indicates that when used properly, formative assessment can lead to significant learning gains and enhance students' self-efficacy. Drawing on previous research and a framework of relational pedagogy, I studied the positional identities claimed, assigned and negotiated by a middle school science teacher and her students during formative assessment interactions. Critical discourse analysis was used to analyze classroom interactions, teacher debriefings and student interviews. Findings from this study indicated that the teacher normatively positioned herself as authority during formative assessment interactions, yet students were not completely powerless. Through assertions of content knowledge and re-directions of topical focus, students positioned themselves actively and had the capacity to influence the direction and focus of formative assessment. Outside of classroom instruction, the teacher simultaneously positioned herself as both hindered by institutional structures yet actively subverted those structures in both covert and overt ways in the service of meaningful science learning. As indicated from interviews and SPAQ questionnaire responses, many students in this classroom positioned themselves positively in relation to science, the teacher and her methods of assessment, while some felt marginalized. This research has implications for the ways in which formative assessment is used to support teaching and learning in science classrooms. Findings from this study indicate that formative assessment is not simply an instrumental act carried out by teachers, but rather is a relational process that necessarily involves students. As a result, formative assessment should balance authoritative and dialogic discourse as a means for supporting and engaging students as

  12. Bacterial bioleaching of low grade nickel limonite and saprolite ores by mixotrophic bacteria

    Directory of Open Access Journals (Sweden)

    Chaerun Siti Khodijah

    2016-01-01

    Full Text Available Utilization of indigenous bacteria should be considered to establish a successful biohydrometallurgical process. In this study, mixrotrophic iron-oxidizing bacterial consortia consisting of Comamonas testosteroni, Alicyclobacillus ferrooxydans and Pantoea septic which were isolated from Indonesian mineral ores were examined to determine their abilities to recover nickel from limonite and saprolite ores in the bioleaching experiments using stirred tank reactors. The nickel bioleaching experiments inoculated with the bacterial consortia were carried out using coarse limonite ores and weathered saprolite ores with pulp density of 10% w/v. Abiotic controls were also carried out replacing the inocula by the sterile medium. The bioleaching processes were monitored by measuring Ni and Fe contents and pH of the leaching solution as well as the total bacterial enzymatic activity measured as FDA hydrolytic activity. The effect of leaching on the mineralogy of laterite ores was investigated by the scanning electron microscope equipped with energy-dispersive spectroscopy (SEM-EDS and X-ray powder diffraction (XRD. After 28 days of incubation, the FDA hydrolytic activity was observed in both bioleaching experiments containing limonite (17.2 μg fluorescein/mL and saprolite ores (16.9 μg fluorescein/mL. The leached Ni and Fe in the bioleaching experiments containing limonite ores (30% Ni and 5.6% Fe was greater than that in abiotic controls (1% Ni and 0.1% Fe with the pH range of 2.5 to 3.5. However, the bacterial consortia were less capable of bioleaching of Ni (2.5% with the similar leached Fe (6% from the saprolite ores. In abiotic controls, the medium pH remained relatively constant (pH 6. It was concluded that these bacterial isolated as the consortium were capable of nickel bioleaching (precious metal more effectively than iron (gangue metal, thus being applicable to the commercial processing of the difficult-to-process low-grade nickel laterite ores

  13. The Star Formation Relation for Regions in the Galactic Plane: The Effect of Spatial Resolution

    CERN Document Server

    Vutisalchavakul, Nalin; Battersby, Cara

    2014-01-01

    We examined the relations between molecular gas surface density and star formation rate surface density in a 11 square degree region of the Galactic Plane. Dust continuum at 1.1 mm from the Bolocam Galactic Plane Survey and 22 micron emission from the WISE All-sky survey were used as tracers of molecular gas and star formation rate, respectively, across Galactic longitude of 31.5 > l > 20.5 and Galactic latitude of 0.5 > b > -0.5. The relation was studied over a range of resolutions from 33 arcsecond to 20 arcminute by convolving images to larger scales. The pixel-by-pixel correlation between 1.1 mm and 22 micron increases rapidly at small scales and levels off at the scale of 5 - 8 arcminute. We studied the star formation relation based on pixel-by-pixel analysis and 1.1 mm and 22 micron peaks analysis. The star formation relation was found to be nearly linear with no significant changes in the form of the relation across all spatial scales and lie above the extragalactic relation from Kennicutt (1998). The ...

  14. 3-D ore body modeling and structural settings of syn-to late orogenic Variscan hydrothermal mineralization, Siegerland district, Rhenish Massif, NW Germany

    Science.gov (United States)

    Peters, Meike; Hellmann, André; Meyer, Franz Michael

    2013-04-01

    The Siegerland district is located in the fold-and thrust-belt of the Rhenish Massif and hosts diverse syn-to late orogenic mineralization styles. Peak-metamorphism and deformation occurred at 312-316±10 Ma (Ahrendt et al., 1978) at temperature-pressure conditions of 280-320°C and 0.7-1.4 kbar (Hein, 1993). In addition to syn-orogenic siderite-quartz mineralization at least four different syn-to late orogenic mineralization stages are identified comprising Co-Ni-Cu-Au, Pb-Zn-Cu, Sb-Au, and hematite-digenite-bornite ores (Hellmann et al., 2012). The earliest type of syn-orogenic ore mineralization is formed by siderite-quartz veins, trending N-S, E-W and NE-SW. The vein systems are closely related to fold and reverse fault geometries (Hellmann et al., 2012). The most important structural feature is the first-order Siegen main reverse fault showing an offset into three major faults (Peters et al., 2012). The structural control on ore formation is demonstrated by the Co-Ni-Cu-Au mineralization generally hosted by NE-ENE trending reverse faults and associated imbrication zones that have reactivated the older siderite-quartz veins. In this study, we developed a 3-D model of the Alte Buntekuh ore bodies in the Siegerland district, using Datamine Studio3 to investigate the structural setting of Co-Ni-Cu-Au mineralization. The salient structural and spatial data for the 3-D model were taken from old mine level plans as well as from geological and topographical maps. The ore bodies are located immediately in the hanging wall of the southern branch of the Siegen main reverse fault (Peters et al., 2012). From the model it becomes obvious, that the earlier siderite-quartz veins, dipping steeply to the NW, are cross-cut and segmented by oppositely dipping oblique reverse faults. Individual ore body segments are rotated and displaced, showing a plunge direction to the SW. The 3-D model further reveals the presence of hook-like, folded vein arrays, highly enriched in cobalt

  15. Automated microscopic characterization of metallic ores with image analysis: a key to improve ore processing. II: metallogenetic discriminating criteria; Reconocimiento automatizado de menas metalicas mediante analisis digital de imagen: un apoyo al proceso mineralurgico. II: criterios metalogeneticos discriminantes

    Energy Technology Data Exchange (ETDEWEB)

    Castroviejo, R.; Berrezueta, E.

    2009-07-01

    ore microscopy may furnish very important information for geo metallurgists, but todays needs for automation are difficult to meet with the optical microscope unless and adequate methodology is developed. Some limitations of the routine procedure, related to risks of mis identification caused by the spectral similarity of some ores, ask for complementary criteria. Defining ore deposit typologies and the corresponding assemblages guides the choice of species and limits the number. Comparison of the reflectance values of the ores in each mineral association defined shows that their automated identification is possible in most of the common occurrence. The number of species to be actually considered being greatly limited, performance is increased. The system is not intended to substitute for a mineralogist, but to enhance enormously his performance, while offering the industry an economic procedure to procedure a wealth of information which would not be possible with traditional methods, as the point counter. (Author) 33 refs.

  16. Method for the production of mineral wool and iron from serpentine ore

    Science.gov (United States)

    O'Connor, William K.; Rush, Gilbert E.; Soltau, Glen F.

    2011-10-11

    Magnesium silicate mineral wools having a relatively high liquidus temperature of at least about 1400.degree. C. and to methods for the production thereof are provided. The methods of the present invention comprise melting a magnesium silicate feedstock (e.g., comprising a serpentine or olivine ore) having a liquidus temperature of at least about 1400.degree. C. to form a molten magnesium silicate, and subsequently fiberizing the molten magnesium silicate to produce a magnesium silicate mineral wool. In one embodiment, the magnesium silicate feedstock contains iron oxide (e.g., up to about 12% by weight). Preferably, the melting is performed in the presence of a reducing agent to produce an iron alloy, which can be separated from the molten ore. Useful magnesium silicate feedstocks include, without limitation, serpentine and olivine ores. Optionally, silicon dioxide can be added to the feedstock to lower the liquidus temperature thereof.

  17. Galaxy Zoo: the dependence of the star formation-stellar mass relation on spiral disk morphology

    CERN Document Server

    Willett, Kyle W; Simmons, Brooke D; Masters, Karen L; Skibba, Ramin A; Kaviraj, Sugata; Melvin, Thomas; Wong, O Ivy; Nichol, Robert C; Cheung, Edmond; Lintott, Chris J; Fortson, Lucy

    2015-01-01

    We measure the stellar mass-star formation rate relation in star-forming disk galaxies at z1. Of the galaxies lying significantly above the M-SFR relation in the local Universe, more than 50% are mergers. We interpret this as evidence that the spiral arms, which are imperfect reflections of the galaxy's current gravitational potential, are either fully independent of the various quenching mechanisms or are completely overwhelmed by the combination of outflows and feedback. The arrangement of the star formation can be changed, but the system as a whole regulates itself even in the presence of strong dynamical forcing.

  18. Effect of MgO and Al2O3 on liquid phase formation in the sintering process of iron ore powder%MgO 和 Al2O3对铁矿粉烧结液相生成的影响

    Institute of Scientific and Technical Information of China (English)

    邓涛; 曹雪洋; 王建超

    2015-01-01

    为阐述烧结过程熔融机制和成矿机制,明确 MgO、Al2 O3质量分数对烧结液相生成和矿物组成的影响是至关重要的。利用 Factsage 软件计算 Fe2 O3-SiO2-CaO-Al2 O3-MgO 体系的液相生成,计算氧分压在500 Pa 时,不同温度,不同 MgO、Al2 O3质量分数下体系液相生成和液相区分布的影响。通过烧结试验,分析烧结矿的矿相和矿物成分,结合软件计算得出烧结矿中 MgO 质量分数为2.0%、Al2 O3质量分数为3.0%时其液相量、矿相、矿物成分达到最优适合烧结冶炼的标准。%To illustrate the melting mechanism and mineralization mechanism of sintering process.Making clear the influence of MgO and Al2 O3 content on sintering liquid phase formation and mineral composition is of vital impor-tance.Liquid phase formation of Fe2 O3-SiO2-CaO-Al2 O3-MgO system is calculated by Factsage software.As well as the effect of variation MgO and Al2 O3 content on liquid phase formation and distribution under different tempera-tures at oxygen partial pressure of 500 Pa.Through the sintering experiment,mineral phase and mineral composition of sinter ore are analyzed.The optimal sintering smelting standard for mass fraction of liquid phase,miner phase and mineral composition is concluded with the software calculation when the content of MgO and Al2 O3 is 2.0% and 3.0% in sinter respectively.

  19. The Relative Rate of LGRB Formation as a Function of Metallicity

    CERN Document Server

    Graham, J F

    2015-01-01

    There is now strong evidence that Long-duration Gamma-Ray Bursts (LGRBs) are preferentially formed in low-metallicity environments. However, the magnitude of this effect, and its functional dependence on metallicity have not been well characterized. In our previous paper, Graham & Fruchter (2013), we compared the metallicity distribution of LGRB host galaxies to the that of star forming galaxies in the local universe. Here we build upon this work by in effect dividing one distribution by the other, and thus directly determine the relative rate of LGRB formation as a function of metallicity in the low-redshift universe. We find a dramatic cutoff in LGRB formation above a metallicity of log(O/H)}+12 ~ 8.3 in the KK04 scale, with LGRBs forming >25 times more frequently per unit star-formation below this cutoff than above. Furthermore, our data suggests that the rate of LGRB formation per unit star formation continues to fall above this break. We estimate the LGRB formation rate per unit star formation may dr...

  20. The first troglobitic Pseudonannolene from Brazilian iron ore caves (Spirostreptida: Pseudonannolenidae).

    Science.gov (United States)

    Iniesta, Luiz Felipe Moretti; Ferreira, Rodrigo Lopes

    2013-01-01

    Pseudonannolene spelaea n. sp. is the first strictly cave-dwelling species described for the family Pseudonannolenidae. It is found in iron ore caves in the Brazilian Amazon. The family Pseudonannolenidae is exclusively Neotropical and frequently found in caves of Brazil, from which 20 species are known. The new species is compared with its congeners and with related cave-dwelling species. The family Pseudonannolenidae is discussed, and comments are presented on the conservation status of the caves where the species is found, which potentially may be the target of anthropogenic impacts resulting from iron ore extraction.

  1. Variations in the uranium isotopic compositions of uranium ores from different types of uranium deposits

    Science.gov (United States)

    Uvarova, Yulia A.; Kyser, T. Kurt; Geagea, Majdi Lahd; Chipley, Don

    2014-12-01

    Variations in 238U/235U and 234U/238U ratios were measured in uranium minerals from a spectrum of uranium deposit types, as well as diagenetic phosphates in uranium-rich basins and peraluminous rhyolites and associated autunite mineralisation from Macusani Meseta, Peru. Mean δ238U values of uranium minerals relative to NBL CRM 112-A are 0.02‰ for metasomatic deposits, 0.16‰ for intrusive, 0.18‰ for calcrete, 0.18‰ for volcanic, 0.29‰ for quartz-pebble conglomerate, 0.29‰ for sandstone-hosted, 0.44‰ for unconformity-type, and 0.56‰ for vein, with a total range in δ238U values from -0.30‰ to 1.52‰. Uranium mineralisation associated with igneous systems, including low-temperature calcretes that are sourced from U-rich minerals in igneous systems, have low δ238U values of ca. 0.1‰, near those of their igneous sources, whereas uranium minerals in basin-hosted deposits have higher and more variable values. High-grade unconformity-related deposits have δ238U values around 0.2‰, whereas lower grade unconformity-type deposits in the Athabasca, Kombolgie and Otish basins have higher δ238U values. The δ234U values for most samples are around 0‰, in secular equilibrium, but some samples have δ234U values much lower or higher than 0‰ associated with addition or removal of 234U during the past 2.5 Ma. These δ238U and δ234U values suggest that there are at least two different mechanisms responsible for 238U/235U and 234U/238U variations. The 234U/238U disequilibria ratios indicate recent fluid interaction with the uranium minerals and preferential migration of 234U. Fractionation between 235U and 238U is a result of nuclear-field effects with enrichment of 238U in the reduced insoluble species (mostly UO2) and 235U in oxidised mobile species as uranyl ion, UO22+, and its complexes. Therefore, isotopic fractionation effects should be reflected in 238U/235U ratios in uranium ore minerals formed either by reduction of uranium to UO2 or chemical

  2. Ore fluid geochemistry of the Jinlongshan Carlin type gold ore belt in Shaanxi Province, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Jinlongshan gold ore belt in southern Shaanxi Province contains a number of Carlin-type gold deposits in the Qinling collisional orogenic belt. Their fluid inclusions are of the Na+ - Cl- type. From the main metallogenic stage to later stages, the total quantity of anions and cations, temperature and deoxidation parameter (R) for fluid inclusions all gradu ally decreased, suggesting the gradual intensification of fluid oxidation, the reduction of met allogenic depth and the input of meteoric water and organic components. The deposits were formed during crustal uplifting and hence had similar tectonic settings to orogenic gold depos its. The CO2 contents and CO2/H2O values of the ore fluid increased from early to late sta ges, and the wall-rock alteration is represented by decarbonation, which is inconsistent with the characteristics of orogenic gold deposits. It is also discovered that Na + , K + ,SO42-, Cl-and the total amounts of anions and cations in the inclusions in quartz are higher than those in the coexisting calcite. The H, O and C isotope ratios indicate that the ore fluid was sourced from meteoric water and metamorphic devolatilisation of the sedimentary rocks that host the ores. The high background δ18O and δ13C values of wall rocks resulted in high δ18O and δ13 C values of ore fluid and also high δ 18 O and δ 13 C values of hydrothermal minerals such as quartz and carbonate. The carbon in ore fluid stemmed largely from the hosting strata. The δ 18O and δ13C values of Fe-calcite and the δD values of fluid inclusions are lower than those of calcite and quartz. In terms of the theory of coordination chemistry, all these differences can be ascribed to water-rock interaction in the same fluid system, instead, to the multi source of ore fluid.

  3. Analytical fingerprint for tantalum ores from African deposits

    Science.gov (United States)

    Melcher, F.; Graupner, T.; Sitnikova, M.; Oberthür, T.; Henjes-Kunst, F.; Gäbler, E.; Rantitsch, G.

    2009-04-01

    Illegal mining of gold, diamonds, copper, cobalt and, in the last decade, "coltan" has fuelled ongoing armed conflicts and civil war in a number of African countries. Following the United Nations initiative to fingerprint the origin of conflict materials and to develop a traceability system, our working group is investigating "coltan" (i.e. columbite-tantalite) mineralization especially in Africa, also within the wider framework of establishing certified trading chains (CTC). Special attention is directed towards samples from the main Ta-Nb-Sn provinces in Africa: DR Congo, Rwanda, Mozambique, Ethiopia, Egypt and Namibia. The following factors are taken into consideration in a methodological approach capable of distinguishing the origin of tantalum ores and concentrates with the utmost probability: (1) Quality and composition of coltan concentrates vary considerably. (2) Mineralogical and chemical compositions of Ta-Nb ores are extremely complex due to the wide range of the columbite-tantalite solid solution series and its ability to incorporate many additional elements. (3) Coltan concentrates may contain a number of other tantalum-bearing minerals besides columbite-tantalite. In our approach, coltan concentrates are analyzed in a step-by-step mode. State-of-the-art analytical tools employed are automated scanning electron microscopy (Mineral Liberation Analysis; MLA), electron microprobe analysis (major and trace elements), laser ablation-ICP-MS (trace elements, isotopes), and TIMS (U-Pb dating). Mineral assemblages in the ore concentrates, major and trace element concentration patterns, and zoning characteristics in the different pegmatites from Africa distinctly differ from each other. Chondrite-normalized REE distribution patterns vary significantly between columbite, tantalite, and microlite, and also relative to major element compositions of columbites. Some locations are characterized by low REE concentrations, others are highly enriched. Samples with

  4. USEFUL RELATIVE MOTION DESCRIPTION METHOD FOR PERTURBATIONS ANALYSIS IN SATELLITE FORMATION FLYING

    Institute of Scientific and Technical Information of China (English)

    MENG Xin; LI Jun-feng; GAO Yun-feng

    2005-01-01

    A set of parameters called relative orbital elements were defined to describe the relative motion of the satellites in the formation flying. With the help of these parameters, the effect of the perturbations on the relative orbit trajectory and geometric properties of satellite formation can be easily analyzed. First,the relative orbital elements are derived, and pointed out: if the eccentricity of the leading satellite is a small value, the relative orbit trajectory is determined by the intersection between an elliptic cylinder and a plane in the leading satellite orbit frame reference; and the parameters that describe the elliptic cylinder and the plane can be used to obtain the relative orbit trajectory and the relative orbital elements. Second, by analyzing the effects of gravitational perturbations on the relative orbit using the relative orbital elements,it is found that the propagation of a relative orbit consists of two parts: one is the drift of the elliptic cylinder; and the other is the rotation of the plane resulted from the rotation of the normal of the plane. Meanwhile, the analytic formulae for the drift and rotation rates of a relative trajectory under gravitational perturbations are presented. Finally, the relative orbit trajectory and the corresponding changes were analyzed with respect to the J2 perturbation.

  5. REE Geochemistry of Sulfides from the Huize Zn-Pb Ore Field, Yunnan Province: Implication for the Sources of Ore-forming Metals

    Institute of Scientific and Technical Information of China (English)

    LI Wenbo; HUANG Zhilong; QI Liang

    2007-01-01

    REE abundances in sulfides from the Huize Zn-Pb ore field were determined with the ICPMS after preconcentration. The REE abundances in 26 sulfide samples (including pyrite, galena and sphalerite) are very low, with the ΣREE ranging from 1.6×10-9 to 166.8×10-9. Their LREE/HREE ratios range from 7.6 to 98, showing LREE enrichment relatively. The δEu values are below 1, indicating that they were deposited from an Eu-depleted and reducing fluid-system. Similar to the ore-hosting carbonate strata, calcite separates from carbonate veinlets filling in the fractures or faults crosscutting the carbonate strata also show clear Eu-depletion. This indicates that the carbonate veinlets and their parent fluid was possibly sourced from the strata and inherited the REE geochemical features of the strata. Therefore, REE-geochemical characteristics of both the sulfides and calcites, which were deposited from an ore-forming hydrothermal system, are similar to those of carbonate strata, and strongly suggest that the ore metals were mainly sourced from carbonate strata.

  6. Ore-controlling Factors and a Metallogenic Model for the Xianglushan Tungsten-Ore Field in Northern Jiangxi Province%赣北香炉山钨矿田矿床控制因素及成矿模式

    Institute of Scientific and Technical Information of China (English)

    陈波; 周贤旭

    2012-01-01

    The Xianglushan tungsten-ore field is part of the Jiuling-Zhanggongshan W-Sn metallogenic belt in northern Jiangxi Province. Combining the ore field exploration in recent years, this paper researches the ore-controlling factors on the basis of geological background of this ore field. The result shows that the impure limestone combination in the Upper Sinian and Cambrian strata is closely related to mineralization in the area. Folds are the major controlling structures in the ore field. Faults and interlayer fracture zones control the ore body position. The Yanshanian magmatic activities provided ore -forming material sources and played an important role in the process of ore fluid migration and deposition. The main ore bodies, hosted in the pyroxene -biotite metamorphic belt, are related to greisenization alteration. This article establishes a metallogenetic model for the Xainghushan tungsten ore field. It may have important guiding significance for the prediction of ore deposit and resources prospecting and exploitation. It can be also used as a reference in searching for similar deposits in the southern margin of the Yangtze Plate.%香炉山矿田是赣北九岭—鄣公山钨锡成矿带的组成部分。本文结合近年来矿田的勘查找矿成果,在分析矿田地质背景的基础上,研究了矿床的控矿因素。认为该区震旦系上统和寒武系地层中的不纯灰岩类组合与成矿关系密切,控制矿田的主体构造是褶皱;断裂及层间破碎带控制矿体的定位,燕山期岩浆活动不仅提供成矿物质来源;同时在矿液的运移和淀积过程中发挥了重要作用,主要矿体均赋存在透辉石—黑云母变质带并与云英岩化等蚀变有关,在此基础上建立了成矿模式。对矿田下步的矿床预测和勘查开发具有重要的指导意义。同时,对扬子板块南缘相似类别矿床的找矿工作起着一定的借鉴作用。

  7. Isotopic indication to source of ore materials and fluids of the Wangfeng gold deposit in Tianshan: A case study of metallogenesis during collisional orogenesis

    Institute of Scientific and Technical Information of China (English)

    陈华勇; 鲍景新; 张增杰; 刘玉琳; 倪培; 凌洪飞

    2000-01-01

    The Wangfeng gold deposit is one of the five most important gold deposits in the Tian-shan. Studies of its metallogenic time, space, geodynamic background, ore feature and ore fluid have proved that the deposit formed in the late Paleozoic continental collision, and consequently is a suitable delegate to probe mineralizing regularities during collisiona! orogenesis. Isotopic studies including O, D, C, S, Pb and Sr reveal ore materials derived from sedimentary association (including carbonate and sulfate), which further refers to the Hercynian carbonate-silicolite-argillite formation north to Wangfeng camp. At the end of Paleozoic, the southward intracontinental subduction of Hercynian synthem along the Hongwuyueqiao fault down to the Central Tianshan terrane induced large-scale fluidization which extracted and out-transported ore materials from Hercynian synthem upto shallow fair positions, and finally resulted in the formation of the Wangfeng deposit. This study excludes the possibility of other tecton

  8. Future health-related behavioral intention formation: the role of affect and cognition.

    Science.gov (United States)

    Richardson, Jessica G; Trafimow, David; Madson, Laura

    2012-01-01

    This study investigated the differential contribution of affect and cognition to behavioral intention formation during pursuit of future health-related goals. Cognitive evaluations, affective evaluations and behavioral intentions were measured for each of 32 health-related behaviors. The timeframes of the cognitive/affective measures and the behavioral intention measure were varied between current and future timeframes creating four different conditions. Within-participants correlations between affect and intentions and cognition and intentions were calculated to determine the contribution of each factor to behavioral intention formation in the different timeframes. Results did not support the hypothesis that a shift from a reliance on affect to a reliance on cognition would occur as temporal distance increased. Within-participants analyses revealed a decrease in the contribution of cognition to behavioral intention formation when forming attitudes in the future condition.

  9. Dose calculations for intakes of ore dust

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, R.S

    1998-08-01

    This report describes a methodology for calculating the committed effective dose for mixtures of radionuclides, such as those which occur in natural radioactive ores and dusts. The formulae are derived from first principles, with the use of reasonable assumptions concerning the nature and behaviour of the radionuclide mixtures. The calculations are complicated because these `ores` contain a range of particle sizes, have different degrees of solubility in blood and other body fluids, and also have different biokinetic clearance characteristics from the organs and tissues in the body. The naturally occurring radionuclides also tend to occur in series, i.e. one is produced by the radioactive decay of another `parent` radionuclide. The formulae derived here can be used, in conjunction with a model such as LUDEP, for calculating total dose resulting from inhalation and/or ingestion of a mixture of radionuclides, and also for deriving annual limits on intake and derived air concentrations for these mixtures. 15 refs., 14 tabs., 3 figs.

  10. Evolutionary and geological factors controlling endogenic uranium mineralization and the potential for the discovery of new ore districts

    Science.gov (United States)

    Mashkovtsev, G. A.; Miguta, A. K.; Shchetochkin, V. N.

    2015-03-01

    The exhaustion of known surface and near-surface high-grade uranium deposits poses the serious problem of prospecting and exploration of new large endogenic deposits. A comparison of large data sets for endogenic deposits from the world's major uranium districts allowed the authors to develop an evolutionary geological model of large-scale uranium ore genesis, which reflects the succession and nature of preore, ore-forming, and post-ore processes. The study reveals a combination of general (recurrent) factors controlling the formation of ore districts with large-scale uranium mineralization regardless of the genesis and timing of the mineralization. At the same time, these factors depend on the regional setting and can vary considerably among deposits of the same type localized in different tectonic blocks with different characteristics and structural evolution. In connection with this, the exploration of major genetic types of deposits requires the application of specified criteria. Along with the consideration of the evolutionary geological model of ore formation, the study discusses a variety of tectono-magmatic, mineralogical, geochemical, radiogeochemical, and physicochemical factors and indications in three uranium districts (the Streltsovskoe, Elkon, and Central Ukrainian districts), which can form the basis for further uranium prospecting and exploration. Using a combination of favorable prerequisite conditions the study compares the possibilities for the discovery of large endogenic uranium deposits in several regions of Russia.

  11. Relative navigation for satellite formation flight using a continuous-discrete converted measurement Kalman filter

    Institute of Scientific and Technical Information of China (English)

    XUE Dan; CAO Xi-bin

    2008-01-01

    The present paper develops an approach of relative orbit determination for satellite formation flight. Inter-satellite measurements by the onboard devices of the satellite were chosen to perform this relative naviga-tion, and the equations of relative motion expressed in the Earth Centered Inertial frame were used to eliminate the assumption of the circular reference orbit. The relative orbit estimation was achieved through a continuous-discrete converted measurement Kalman filter design, in which the measurements were transformed to the iner-tial frame to avoid the linearization error of the observation equation. In addition, the situation of the coarse measurement period (only microwave radar measurements are available) existing was analyzed. The numerical simulation results verify the validity of the navigation approach, and it has been proved that this approach can be applied to the formation with an elliptical reference orbit.

  12. The Mbh-sigma relation as a constraint on the formation of elliptical galaxies

    CERN Document Server

    Ciotti, L

    2001-01-01

    Most elliptical galaxies contain central black holes, whose masses scale proportionally to the observed central velocity dispersions of the host galaxies according to the so-called Mbh-sigma relation. Here we discuss some consequences that can be derived by combining the Mbh-sigma relation with the scaling relation describing the Fundamental Plane of elliptical galaxies. In particular, the possibility of substantial dissipationless merging in the formation and evolution of elliptical galaxies is discussed. Enforcing the merger end-products to satisfy the two scaling relations mentioned above, a major role of dissipation in galaxy formation is strongly suggested by our analysis. Moreover, we show that existing observational data may shed some light on the complex process of black hole merging.

  13. On the complex formation approach in modeling predator prey relations, mating, and sexual disease transmission

    Directory of Open Access Journals (Sweden)

    Horst R. Thieme

    2000-10-01

    Full Text Available Complex formation is used as a unified approach to derive representations and approximations of the functional response in predator prey relations, mating, and sexual disease transmission. Applications are given to the impact of a generalist predator on a prey population and the spread of a sexually transmitted disease in a multi-group heterosexual population.

  14. Cognitive Association Formation in Episodic Memory: Evidence from Event-Related Potentials

    Science.gov (United States)

    Kim, Alice S. N.; Vallesi, Antonino; Picton, Terence W.; Tulving, Endel

    2009-01-01

    The present study focused on the processes underlying cognitive association formation by investigating subsequent memory effects. Event-related potentials were recorded as participants studied pairs of words, presented one word at a time, for later recall. The findings showed that a frontal-positive late wave (LW), which occurred 1-1.6 s after the…

  15. Relative Humidity as an Indicator for Cloud Formation over Heterogeneous land surfaces

    NARCIS (Netherlands)

    Heerwaarden, van C.C.; Vilà-Guerau de Arellano, J.

    2008-01-01

    The influence of land surface heterogeneity on potential cloud formation is investigated using relative humidity as an indicator. This is done by performing numerical experiments using a large-eddy simulation model (LES). The land surface in the model was divided into two patches that had the same s

  16. Variation in brachial plexus formation, branching pattern and relation with major vessels

    Directory of Open Access Journals (Sweden)

    G. Anwer Khan

    2014-08-01

    Conclusion: The present study carried out on adult human cadavers revealed some rare variations in the formation, branching pattern and relations of the brachial plexus. These variations are of clinical significance for the surgeons, radiologists and the anesthesiologists. [Int J Res Med Sci 2014; 2(4.000: 1591-1594

  17. Analytical solution of perturbed relative motion: an application of satellite formations to geodesy

    Science.gov (United States)

    Wnuk, Edwin

    In the upcoming years, several space missions will be operated using a number of spacecraft flying in formation. Clusters of spacecraft with a carefully designed orbits and optimal formation geometry enable a wide variety of applications ranging from remote sensing to astronomy, geodesy and basic physics. Many of the applications require precise relative navigation and autonomous orbit control of satellites moving in a formation. For many missions a centimeter level of orbit control accuracy is required. The GRACE mission, since its launch in 2002, has been improving the Earth's gravity field model to a very high level of accuracy. This mission is a formation flying one consisting of two satellites moving in coplanar orbits and provides range and range-rate measurements between the satellites in the along-track direction. Future geodetic missions probably will employ alternative architectures using additional satellites and/or performing out-of-plane motion, e.g cartwheel orbits. The paper presents an analytical model of a satellite formation motion that enables propagation of the relative spacecraft motion. The model is based on the analytical theory of satellite relative motion that was presented in the previous our papers (Wnuk and Golebiewska, 2005, 2006). This theory takes into account the influence of the following gravitational perturbation effects: 1) zonal and tesseral harmonic geopotential coefficients up to arbitrary degree and order, 2) Lunar gravity, 3) Sun gravity. Formulas for differential perturbations were derived with any restriction concerning a plane of satellite orbits. They can be applied in both: in plane and out of plane cases. Using this propagator we calculated relative orbits and future relative satellite positions for different types of formations: in plane, out of plane, cartwheel and others. We analyzed the influence of particular parts of perturbation effects and estimated the accuracy of predicted relative spacecrafts positions

  18. Iron ore weathering potentials of ectomycorrhizal plants.

    Science.gov (United States)

    Adeleke, R A; Cloete, T E; Bertrand, A; Khasa, D P

    2012-10-01

    Plants in association with soil microorganisms play an important role in mineral weathering. Studies have shown that plants in symbiosis with ectomycorrhizal (ECM) fungi have the potential to increase the uptake of mineral-derived nutrients. However, it is usually difficult to study many of the different factors that influence ectomycorrhizal weathering in a single experiment. In the present study, we carried out a pot experiment where Pinus patula seedlings were grown with or without ECM fungi in the presence of iron ore minerals. The ECM fungi used included Pisolithus tinctorius, Paxillus involutus, Laccaria bicolor and Suillus tomentosus. After 24 weeks, harvesting of the plants was carried out. The concentration of organic acids released into the soil, as well as potassium and phosphorus released from the iron ore were measured. The results suggest that different roles of ectomycorrhizal fungi in mineral weathering such as nutrient absorption and transfer, improving the health of plants and ensuring nutrient circulation in the ecosystem, are species specific, and both mycorrhizal roots and non-mycorrhizal roots can participate in the weathering process of iron ore minerals.

  19. Vertical mill simulation applied to iron ores

    Directory of Open Access Journals (Sweden)

    Douglas Batista Mazzinghy

    2015-04-01

    Full Text Available The application of vertical mills in regrind circuits is consolidated. This type of mill is now attracting interest in primary grinding applications, due to its higher efficiency when compared to ball mills, which are usually used at this stage. In this study, a coarse sample of iron ore was tested in a pilot scale grinding circuit with a vertical mill. Other three samples of pellet feed had already been tested with the methodology used in this study. The sample of coarse iron ore was characterized in laboratory tests carried out in a small batch ball mill. Selection and breakage function parameters were determined from the laboratory tests. The parameters were then used for simulating the pilot scale tests using Modsim™ software. The model previously implemented in Modsim™ has been successfully applied to represent the vertical mill operated with different ores. The simulations produced particle size distributions that were very close to the actual size distributions, and the predictions were accomplished only by imputing the calibrated parameters from the batch tests, the power draw and the feed size distribution of the pilot tests. The methodology is therefore useful for scale-up and simulation of vertical mills, only requiring laboratory tests that can be carried out in standard laboratory batch ball mills with small amounts of samples.

  20. Reservoir condition special core analyses and relative permeability measurements on Almond formation and Fontainebleu sandstone rocks

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, D.

    1993-11-01

    This report describes the results from special core analyses and relative permeability measurements conducted on Almond formation and Fontainebleu sandstone plugs. Almond formation plug tests were performed to evaluate multiphase, steady-state,reservoir-condition relative permeability measurement techniques and to examine the effect of temperature on relative permeability characteristics. Some conclusions from this project are as follows: An increase in temperature appeared to cause an increase in brine relative permeability results for an Almond formation plug compared to room temperature results. The plug was tested using steady-state oil/brine methods. The oil was a low-viscosity, isoparaffinic refined oil. Fontainebleu sandstone rock and fluid flow characteristics were measured and are reported. Most of the relative permeability versus saturation results could be represented by one of two trends -- either a k{sub rx} versus S{sub x} or k{sub rx} versus Sy trend where x and y are fluid phases (gas, oil, or brine). An oil/surfactant-brine steady-state relative permeability test was performed to examine changes in oil/brine relative permeability characteristics from changes in fluid IFTS. It appeared that, while low interfacial tension increased the aqueous phase relative permeability, it had no effect on the oil relative permeability. The BOAST simulator was modified for coreflood simulation. The simulator was useful for examining effects of variations in relative permeability and capillary pressure functions. Coreflood production monitoring and separator interface level measurement techniques were developed using X-ray absorption, weight methods, and RF admittance technologies. The three types of separators should be useful for routine and specialized core analysis applications.

  1. Formation of radical anions of radiosensitizers and related model compounds via electrospray ionization

    DEFF Research Database (Denmark)

    Feketeová, Linda; Albright, Abigail L; Sørensen, Brita Singers

    2014-01-01

    Radiosensitizers are used in radiotherapy to enhance tumour control of radioresistant hypoxic tumours. While the detailed mechanism of radiosensitization is still unknown, the formation of radical anions is believed to be a key step. Thus understanding the ionization reactions of radiosensitizers......, misonidazole and related compounds using a hybrid linear ion trap – Fourier Transform Ion Cyclotron Resonance mass spectrometer (Finnigan-LTQ-FT). A key finding is that negative electrospray ionization of these radiosensitizers leads to the formation of radical anions, allowing their fragmentation reactions...

  2. General monogamy relation for the entanglement of formation in multiqubit systems.

    Science.gov (United States)

    Bai, Yan-Kui; Xu, Yuan-Fei; Wang, Z D

    2014-09-01

    We prove exactly that the squared entanglement of formation, which quantifies the bipartite entanglement, obeys a general monogamy inequality in an arbitrary multiqubit mixed state. Based on this kind of exotic monogamy relation, we are able to construct two sets of useful entanglement indicators: the first one can detect all genuine multiqubit entangled states even in the case of the two-qubit concurrence and n-tangles being zero, while the second one can be calculated via quantum discord and applied to multipartite entanglement dynamics. Moreover, we give a computable and nontrivial lower bound for multiqubit entanglement of formation.

  3. Oil,Gas and Ore

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The government is weighing the timing of readjusting its tax policy on fossil fuels what if the resource tax on minerals was lifted? "It might dampen the performance of resource-related enterprises, giving rise to more operational problems," said Wu Qiang, a professor at Beijing Technology and Business University.

  4. Galaxy Zoo: the dependence of the star formation-stellar mass relation on spiral disc morphology

    Science.gov (United States)

    Willett, Kyle W.; Schawinski, Kevin; Simmons, Brooke D.; Masters, Karen L.; Skibba, Ramin A.; Kaviraj, Sugata; Melvin, Thomas; Wong, O. Ivy; Nichol, Robert C.; Cheung, Edmond; Lintott, Chris J.; Fortson, Lucy

    2015-05-01

    We measure the stellar mass-star formation rate (SFR) relation in star-forming disc galaxies at z ≤ 0.085, using Galaxy Zoo morphologies to examine different populations of spirals as classified by their kiloparsec-scale structure. We examine the number of spiral arms, their relative pitch angle, and the presence of a galactic bar in the disc, and show that both the slope and dispersion of the M⋆-SFR relation is constant when varying all the above parameters. We also show that mergers (both major and minor), which represent the strongest conditions for increases in star formation at a constant mass, only boost the SFR above the main relation by ˜0.3 dex; this is significantly smaller than the increase seen in merging systems at z > 1. Of the galaxies lying significantly above the M⋆-SFR relation in the local Universe, more than 50 per cent are mergers. We interpret this as evidence that the spiral arms, which are imperfect reflections of the galaxy's current gravitational potential, are either fully independent of the various quenching mechanisms or are completely overwhelmed by the combination of outflows and feedback. The arrangement of the star formation can be changed, but the system as a whole regulates itself even in the presence of strong dynamical forcing.

  5. 40 CFR 440.10 - Applicability; description of the iron ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions of this subpart A are applicable to discharges from (a) mines operated to obtain iron ore, regardless of the type of ore...

  6. EXPLANATORY MODEL OF SPOT PRICE OF IRON ORE

    Directory of Open Access Journals (Sweden)

    Juan Enrique Villalva A.

    2015-11-01

    Full Text Available The objective of this study was to construct an explanatory model of the spot price of iron ore in the international market. For this, the method of multiple linear regressions was used. As a dependent variable, the spot price of iron ore (62% Fe China Tianjin port was taken, between 2010 and 2013. As independents variables were taken seven variables of international iron ore market. The resulting model includes variables: Iron ore inventory in Chinese ports, Baltic Dry Index (BDI, Iron ore exports from Brazil & Australia and Chinese Rebar Steel Price, as explanatory variables of the behavior of the spot price of iron ore in the international market. The model has an adjusted coefficient of determination R2 of 0.90, and was validated by comparing its predictions vs. known values of 2014.

  7. Assessment of (222)Rn emanation from ore body and backfill tailings in low-grade underground uranium mine.

    Science.gov (United States)

    Mishra, Devi Prasad; Sahu, Patitapaban; Panigrahi, Durga Charan; Jha, Vivekanand; Patnaik, R Lokeswara

    2014-02-01

    This paper presents a comparative study of (222)Rn emanation from the ore and backfill tailings in an underground uranium mine located at Jaduguda, India. The effects of surface area, porosity, (226)Ra and moisture contents on (222)Rn emanation rate were examined. The study revealed that the bulk porosity of backfill tailings is more than two orders of magnitude than that of the ore. The geometric mean radon emanation rates from the ore body and backfill tailings were found to be 10.01 × 10(-3) and 1.03 Bq m(-2) s(-1), respectively. Significant positive linear correlations between (222)Rn emanation rate and the (226)Ra content of ore and tailings were observed. For normalised (226)Ra content, the (222)Rn emanation rate from tailings was found to be 283 times higher than the ore due to higher bulk porosity and surface area. The relative radon emanation from the tailings with moisture fraction of 0.14 was found to be 2.4 times higher than the oven-dried tailings. The study suggested that the mill tailings used as a backfill material significantly contributes to radon emanation as compared to the ore body itself and the (226)Ra content and bulk porosity are the dominant factors for radon emanation into the mine atmosphere.

  8. Geological and Technological Characterization of the Manganese ore Deposits of the Córrego do Cocho Mine, Itapira (SP

    Directory of Open Access Journals (Sweden)

    Nelson Angeli

    2011-12-01

    Full Text Available The objects of this study are three manganese ore deposits and one mine derived from lateritic weathering of gondites(spessartine quartzites. These deposits are associated with Mn-rich garnet metasediments of the Itapira Group (Paleoproterozoicand the reserves were estimated at approximately 2.0 x 106 tons with an average grade of 23% MnO2. The ore minerals arecryptomelane, pyrolusite, lithiophorite, spessartine and psilomelane. Several crystal shapes and textural characteristics wereidentifi ed in this study, which are related to the degree of liberation, as confi rmed by heavy media separation method. In thisstudy, we determined the main characteristics of the liberation of manganese, which is concentrated in the fi ne grain-sizefraction and is lost during ore dressing. Therefore, the low average content of MnO2 (28% is due to this loss, whereas at grainsize of minus 0.074 mm, contents near 40% MnO2 were observed. This suggests that the ore can be used for manufacturingmanganese sulphate fertilizers. A comparative study with the ore deposits located at Ouro Fino (MG, mainly with theCaneleiras mine, showed that higher degree of liberation occurs in the coarse grain-size fractions (0.84 to 0.074 mm withMnO2 content of 38%. As a consequence, the ore can be used for manufacturing Fe-Si-Mn alloys.

  9. Source of ore-forming material for the Huangtuliang gold deposit, Hebei Province and ore prospecting in the deep periphery

    Institute of Scientific and Technical Information of China (English)

    NIU Shuyin; SUN Aiqun; WANG Baode; HAN Yuchou; WEI Minghui; ZHANG Hai; ZHANG Ge; SHI Ping; WANG Wenxing

    2008-01-01

    The Huangtuliang gold deposit is characterized by its wide and large ore belt, stable extension and closely spaced orebodies. Unfortunately, no orebody was found by deep drilling. As a result, ore prospecting in this region was once put into dilemma. Detailed analysis of ore-forming and ore-controlling structures in the mining district by the authors has revealed that the ore-forming and ore-controlling structure in this mining district is a steeply dipping (85°-110°/∠70°-85° N-NNE), spade-shaped ductile shear zone, and the ore-controlling structures are a series of nearly erected second-ordered faults which are developed in the upper part of the ductile shear zone, intersecting with the ductile shear zone. Deep cutting of the ductile shear zone made it possible the ascending of ore fluids from the mantle plume at depth and these ore fluids would migrate upwards along the ductile shear zone under certain temperature and pressure conditions. Along their ascending path, the ore fluids would extract ore-forming elements from the country rocks and the extracted ore-forming elements would be deposited as ores in the hanging-wall second-ordered faults. The reason why no orebody was found in early prospecting at depth is that northward-dipping drilling in the southern part of the shear zone extended so deeply as to be beneath the shear zone. Only shallow-level orebodies could be found by southward-dipping drilling practice in the northern part of the shear zone.The location where deep-seated orebodies occurred shifted northwards and the orebodies occurred at greater depth.Therefore, it is natural that no orebody could be found when drill core passed through the shear zone. After the ore-forming and ore-controlling structures were well understood, the focus of ore prospecting was placed on the deep-level, northward-penetrating veins. In this way a number of new blind orebodies of great thickness have been found. On the basis of research development in the mining

  10. The relation between atomic gas and star formation rate densities in faint irregular galaxies

    CERN Document Server

    Roychowdhury, Sambit; Kaisin, Serafim S; Karachentsev, Igor D

    2014-01-01

    We use data for faint (M_B > -14.5) dwarf irregular galaxies drawn from the FIGGS survey to study the correlation between the atomic gas density (Sigma_gas,atomic) and star formation rate (Sigma_SFR) in the galaxies. The estimated gas phase metallicity of our sample galaxies is Z ~ 0.1 Z_sun. Understanding star formation in such molecule poor gas is of particular importance since it is likely to be of direct relevance to simulations of early galaxy formation. For about 20% (9/43) of our sample galaxies, we find that the HI distribution is significantly disturbed, with little correspondence between the optical and HI distributions. We exclude these galaxies from the comparison. We also exclude galaxies with very low star formation rates, for which stochastic effects make it difficult to estimate the true star formation rates. For the remaining galaxies we compute the Sigma_gas,atomic and Sigma_SFR averaged over the entire star forming disk of the galaxy. For these galaxies we find a nearly linear relation betw...

  11. Release and Formation of Oxidation-Related Aldehydes during Wine Oxidation.

    Science.gov (United States)

    Bueno, Mónica; Carrascón, Vanesa; Ferreira, Vicente

    2016-01-27

    Twenty-four Spanish wines were subjected to five consecutive cycles of air saturation at 25 °C. Free and bound forms of carbonyls were measured in the initial samples and after each saturation. Nonoxidized commercial wines contain important and sensory relevant amounts of oxidation-related carbonyls under the form of odorless bound forms. Models relating the contents in total aldehydes to the wine chemical composition suggest that fermentation can be a major origin for Strecker aldehydes: methional, phenylacetaldehyde, isobutyraldehyde, 2-methylbutanal, and isovaleraldehyde. Bound forms are further cleaved, releasing free aldehydes during the first steps of wine oxidation, as a consequence of equilibrium shifts caused by the depletion of SO2. At low levels of free SO2, de novo formation and aldehyde degradation are both observed. The relative importance of these phenomena depends on both the aldehyde and the wine. Models relating aldehyde formation rates to wine chemical composition suggest that amino acids are in most cases the most important precursors for de novo formation.

  12. Sulfuric acid leaching of mechanically activated manganese carbonate ore

    Directory of Open Access Journals (Sweden)

    Kenan Yıldız

    2010-06-01

    Full Text Available Acidic leaching of mechanically activated manganese ore from Denizli – Tavas was investigated. The ore was activated mechanically in a planetary mill and the amorphisation in manganese structure was analyzed with X-ray diffraction. The parameters in acidic leaching of the ore were milling time, acid concentration and time. All experiments were performed at 25°C with solid to liquid ratio: 1/10. The activation procedure led to amorphization and structural disordering in manganese ore and accelerated the dissolution of manganese in acidic media.

  13. Tectonomagmatic Metallogenic System of Dexing Ore Field, Jiangxi, China

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    13 ore deposits and a large number of ore occurrences cluster in Dexing ore field which is 20 km long and 12 km wide. The tectonic evolution, magmatism, as well as the metallogeny are controlled by the Northeast Jiangxi deep-seated fracture belt (NJDFB). The source is believed to have been derived from the Meso-Neoproterozoic marine volcanism. The magmatic activity of Mesozoic I-type granite could have provided the metal elements, thermal fluid, heat, and the space for ore-forming processes. A unified geological model is proposed, which combines the tectonism, magmatism and metallogeny as the basic control of the giant metal mineralizations.

  14. Pros and Cons,Iron Ore Price Hikes

    Institute of Scientific and Technical Information of China (English)

    Tang Jingtao

    2008-01-01

    @@ Backaround Baostecl and CVRD reached an agreement on the price hikes of 65 percent and 71 percent in February.And in June Baosteel and Rio Tinto which is the largest iron ore company in Australia reached an agreement on the price hikes of 79.88 percent on the iron ore fines and 96.5 percent on the iron ore lumps.This is the first time that two kinds of the iron ore price grew at the same time in Asian market.

  15. Radon emanation from low-grade uranium ore.

    Science.gov (United States)

    Sahu, Patitapaban; Mishra, Devi Prasad; Panigrahi, Durga Charan; Jha, Vivekanand; Patnaik, R Lokeswara

    2013-12-01

    Estimation of radon emanation in uranium mines is given top priority to minimize the risk of inhalation exposure due to short-lived radon progeny. This paper describes the radon emanation studies conducted in the laboratory as well as inside an operating underground uranium mine at Jaduguda, India. Some of the important parameters, such as grade/(226)Ra activity, moisture content, bulk density, porosity and emanation fraction of ore, governing the migration of radon through the ore were determined. Emanation from the ore samples in terms of emanation rate and emanation fraction was measured in the laboratory under airtight condition in glass jar. The in situ radon emanation rate inside the mine was measured from drill holes made in the ore body. The in situ(222)Rn emanation rate from the mine walls varied in the range of 0.22-51.84 × 10(-3) Bq m(-2) s(-1) with the geometric mean of 8.68 × 10(-3) Bq m(-2) s(-1). A significant positive linear correlation (r = 0.99, p 222)Rn emanation rate and the ore grade was observed. The emanation fraction of the ore samples, which varied in the range of 0.004-0.089 with mean value of 0.025 ± 0.02, showed poor correlation with ore grade and porosity. Empirical relationships between radon emanation rate and the ore grade/(226)Ra were also established for quick prediction of radon emanation rate from the ore body.

  16. Effect and behaviour of different substrates in relation to the formation of aerobic granular sludge.

    Science.gov (United States)

    Pronk, M; Abbas, B; Al-Zuhairy, S H K; Kraan, R; Kleerebezem, R; van Loosdrecht, M C M

    2015-06-01

    When aerobic granular sludge is applied for industrial wastewater treatment, different soluble substrates can be present. For stable granular sludge formation on volatile fatty acids (e.g. acetate), production of storage polymers under anaerobic feeding conditions has been shown to be important. This prevents direct aerobic growth on readily available chemical oxygen demand (COD), which is thought to result in unstable granule formation. Here, we investigate the impact of acetate, methanol, butanol, propanol, propionaldehyde, and valeraldehyde on granular sludge formation at 35 °C. Methanogenic archaea, growing on methanol, were present in the aerobic granular sludge system. Methanol was completely converted to methane and carbon dioxide by the methanogenic archaeum Methanomethylovorans uponensis during the 1-h anaerobic feeding period, despite the relative high dissolved oxygen concentration (3.5 mg O2 L(-1)) during the subsequent 2-h aeration period. Propionaldehyde and valeraldehyde were fully disproportionated anaerobically into their corresponding carboxylic acids and alcohols. The organic acids produced were converted to storage polymers, while the alcohols (produced and from influent) were absorbed onto the granular sludge matrix and converted aerobically. Our observations show that easy biodegradable substrates not converted anaerobically into storage polymers could lead to unstable granular sludge formation. However, when the easy biodegradable COD is absorbed in the granules and/or when the substrate is converted by relatively slow growing bacteria in the aerobic period, stable granulation can occur.

  17. The Multiple Factors and Multiple Stages Involved in Sedimentary Ore Genesis

    Institute of Scientific and Technical Information of China (English)

    叶连俊; 陈其英

    1990-01-01

    Sedimentary mineral deposits cannot be formed by any kind of simple chemical reactions,but are products of a complex multi-episodic process depending on multiple factors,The whole process is governed by a combination of sedimentary,geochemical,biogeochemical,organic geochemical,paleoclimatical,mechanical agents as well as by the properties of relevant earth crust segment and its structural making up and tectonic mobility A Sedimentary ore deposit is nothing but a special kind of sedimentary facies,characterized by definite sedimentary assemblages,Different genetic types of ore deposit and different ore associations characterize different sedimentary assemblages in different ore-forming belts.Crustal movement,including orogenic,epeirogenic and,oparticularly eustatic events,controls the formation and distribution of all kinds of sedimentary mineral deposits,most of which occur within the transgression front in the lower part of marine transpressive series.Mineral deposits of economic importance cannot be precipitated directly from sea water,but are products of terrestrial imbibition,biological enrichment and pore water concentration instead,Deposits formed above the wave base in the inner continental shelf under strong dynamic condition of sea water are often large and predominantly clastic in texture with commercial grade.Below the wave base in the outer continental shelf environment,where it is more or less dynamically stagnant and oxygen-deficient,the resulted in dustrial ore deposits are mostly of diagenetic or strata-bound type,formed through deep-burying diagenesis.The theory of multi-factor and multi-episodic metallogenesis includes three major aspects:the ore-forming process,the sedimentary environment and the geological background.The study of the forma tion process itself and the sources of ore-forming elements would provide useful clues to further prospectiong Whereas,invstigations of the sedimentary environments should shed light on the spacial

  18. Reduced mortality rates in a cohort of long-term underground iron-ore miners.

    Science.gov (United States)

    Björ, Ove; Jonsson, Håkan; Damber, Lena; Wahlström, Jens; Nilsson, Tohr

    2013-05-01

    Historically, working in iron-ore mines has been associated with an increased risk of lung cancer and silicosis. However, studies on other causes of mortality are inconsistent and in the case of cancer incidence, sparse. The aim of this study was to examine the association between iron-ore mining, mortality and cancer incidence. A 54-year cohort study on iron-ore miners from mines in northern Sweden was carried out comprising 13,000 workers. Standardized rate ratios were calculated comparing the disease frequency, mortality, and cancer incidence with that of the general population of northern Sweden. Poisson regression was used to evaluate the association between the durations of employment and underground work, and outcome. Underground mining was associated with a significant decrease in adjusted mortality rate ratios for cerebrovascular and digestive system diseases, and stroke. For several outcomes, elevated standardized rate ratios were observed among blue-collar workers relative to the reference population. However, only the incidence of lung cancer increased with employment time underground (P iron-ore mining underground was associated with lower rates regarding several health outcomes. This is possibly explained by factors related to actual job activities, environmental exposure, or the selection of healthier workers for long-term underground employment. Copyright © 2013 Wiley Periodicals, Inc.

  19. Culture-dependent and -independent molecular analysis of the bacterial community within uranium ore.

    Science.gov (United States)

    Islam, Ekramul; Sar, Pinaki

    2011-08-01

    The bacterial community structure within a uranium ore was investigated using culture-dependent and -independent clone library analysis and denaturing gradient gel electrophoresis of 16S rRNA genes. The major aerobic heterotrophic bacteria were isolated and identified, and their resistance to uranium and other heavy metals was characterized. Together with near neutral pH, moderate organic carbon content, elevated U and other heavy metals (V, Ni, Mn, Cu, etc.), the ore showed high microbial counts and phylotype richness. The bacterial community mainly consisted of uncultured Proteobacteria, with the predominance of γ - over β - and α -subdivisions, along with Actinobacteria and Firmicutes. A phylogenetic study revealed that nearly one-third of the community was affiliated to as yet uncultured and unidentified bacteria having a closer relationship to Pseudomonas. Lineages of Burkholderiaceae and Moraxellaceae were relatively more abundant in the total community, while genera affiliated to Xanthomonadaceae and Microbacteriaceae and Exiguobacterium were detected in the culturable fraction. More than 50% of the bacterial isolates affiliated to Stenotrophomonas, Microbacterium, Acinetobacter, Pseudomonas and Enterobacter showed resistance to uranium and other heavy metals. The study showed for the first time that uranium ore harbors major bacterial groups related to organisms having a wide range of environmentally significant functional attributes, and the most abundant members are possibly new groups/taxa. These findings provide new insights into U-ore geomicrobiology that could be useful in biohydrometallurgy and bioremediation applications.

  20. Protestant Evangelical Christian Fathers and Their Intentional Involvement in the Relational Christian Spiritual Formation of Their Children

    Science.gov (United States)

    Clark, Steve Richard

    2013-01-01

    This quantitative study explored paternal intentional involvement in the relational spiritual formation of their children. The main research question was to what degree are Protestant Evangelical fathers intentionally involved in the relational spiritual formation of their children? The research was based on two domains: relational spiritual…

  1. Prospecting For Magnetite Ore Deposits With A Innovative Sensor's of Unique Fundamentally New Magnetometer.

    Science.gov (United States)

    Emelianenko, T. I.; Tachaytdinov, R. S.; Sarichev, V. F.; Kotov, B. V.; Susoeva, G. N.

    After careful study of principles and abilities of all existing magnetmeters of all three revolutions in magnetic prospecting we have come to the conclusion that they cannot solve local guestions of the magnetic prospecting or determine centre coordinates of magnetite ore body before drilling Electromagnetism lows and achievents magnetprospectings and radioelectronics of all 20th century serve as a theoretical base of the "locator". While creating this cardinally new magnetmeter , we borrowed different things from radio-prospectors, magnetprospectors, wireless operators and combined all of them while creating the "locators''. The "locators' construction is bas ed on the "magnetic intensification" principle ,owing to which this "locators" are characterised by hight sensitiveness and ability to determine centers of even little commercial magnetite ore deposits with relatively weak magnetic anomalies. The main advantage of the "locators" over existing ones is that it can solve local questions determine centre coordinates. A remarkably simple locator construction determine direction of the on-surface measurings towards the ore body centre and gives approximate prognosis resourses before/withour/ drilling. The "locators" were worked out for the first time in history , they have 2 licences. The fundamental design and drawbacks of the existing magnetometers have been inherited from the original magnetometre dating back two or three hundred years. The developers of the existing magnetometres have all gone along the same well- beaten track of replacing the primitive sensor in the form of a piece of ore hung on a string at first by an arrow sensor and later by magnetically oriented protons and quanta, with amplification of the sensors' OUTPUT signal. Furthermore, all the existing magnetometres are imperfect in that they, lacking the directivity of the ground-level magnetic measurements, only record the overall magnetic vector field generated by all the ore bodies around the

  2. Biogeometallurgical pre-mining characterization of ore deposits: an approach to increase sustainability in the mining process.

    Science.gov (United States)

    Dold, Bernhard; Weibel, Leyla

    2013-11-01

    Based on the knowledge obtained from acid mine drainage formation in mine waste environments (tailings impoundments and waste rock dumps), a new methodology is applied to characterize new ore deposits before exploitation starts. This gives the opportunity to design optimized processes for metal recovery of the different mineral assemblages in an ore deposit and at the same time to minimize the environmental impact and costs downstream for mine waste management. Additionally, the whole economic potential is evaluated including strategic elements. The methodology integrates high-resolution geochemistry by sequential extractions and quantitative mineralogy in combination with kinetic bioleach tests. The produced data set allows to define biogeometallurgical units in the ore deposit and to predict the behavior of each element, economically or environmentally relevant, along the mining process.

  3. Role of ore mineralogy in optimizing conditions for bioleaching low-grade complex sulphide ores

    Institute of Scientific and Technical Information of China (English)

    P. A. OLUBAMBI; S. NDLOVU; J. H. POTGIETER; J. O. BORODE

    2008-01-01

    The role that ore mineralogy plays in understanding and optimizing the conditions favouring the bioleaching of complex sulphide ore containing high amounts of siderite was studied using mixed cultures of mesophilic bacteria, with emphasis on zinc,lead and copper recoveries. The influencing parameters investigated include particle size, stirring speed, volume of inoculum, pulp density, and pH. The results show that the mixed mesophilic cultures can extract about two and a half times the amount of zinc than copper over an equivalent period of time. The highest zinc and copper recoveries of 89.2% and 36.4% respectively are obtained at particle size of 75 μm, stirring speed of 150 r/min, pulp density of 10% (w/v), 12% (v/v) inoculum concentration, and a pH of 1.6. Variations in elemental composition within different particle sizes resulting from the mineralogy of the ore account for the bioleaching behaviour at varying particle sizes. The dissolution at varying pulp density, volume of inoculum, solution pH and the low solution potential observed are also influenced by ore mineralogy.

  4. Assessment of health risks due to arsenic from iron ore lumps in a beach setting.

    Science.gov (United States)

    Swartjes, Frank A; Janssen, Paul J C M

    2016-09-01

    In 2011, an artificial hook-shaped peninsula of 128ha beach area was created along the Dutch coast, containing thousands of iron ore lumps, which include arsenic from natural origin. Elemental arsenic and inorganic arsenic induce a range of toxicological effects and has been classified as proven human carcinogens. The combination of easy access to the beach and the presence of arsenic raised concern about possible human health effects by the local authorities. The objective of this study is therefore to investigate human health risks from the presence of arsenic-containing iron ore lumps in a beach setting. The exposure scenarios underlying the human health-based risk limits for contaminated land in The Netherlands, based on soil material ingestion and a residential setting, are not appropriate. Two specific exposure scenarios related to the playing with iron ore lumps on the beach ('sandcastle building') are developed on the basis of expert judgement, relating to children in the age of 2 to 12years, i.e., a worst case exposure scenario and a precautionary scenario. Subsequently, exposure is calculated by the quantification of the following factors: hand loading, soil-mouth transfer effectivity, hand-mouth contact frequency, contact surface, body weight and the relative oral bioavailability factor. By lack of consensus on a universal reference dose for arsenic for use in the stage of risk characterization, three different types of assessments have been evaluated: on the basis of the current Provisional Tolerable Daily Intake (PTWI), on the basis of the Benchmark Dose Lower limit (BMDL), and by a comparison of exposure from the iron ore lumps with background exposure. It is concluded, certainly from the perspective of the conservative exposure assessment, that unacceptable human health risks due to exposure to arsenic from the iron ore lumps are unlikely and there is no need for risk management actions. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Bioprocessing of ores: Application to space resources

    Science.gov (United States)

    Johansson, Karl R.

    The role of microorganisms in the oxidation and leaching of various ores (especially those of copper, iron, and uranium) is well known. This role is increasingly being applied by the mining, metallurgy, and sewage industries in the bioconcentration of metal ions from natural receiving waters and from waste waters. It is concluded that bioprocessing using bacteria in closed reactors may be a variable option for the recovery of metals from the lunar regolith. Obviously, considerable research must be done to define the process, specify the appropriate bacteria, determine the necessary conditions and limitations, and evaluate the overall feasibility.

  6. Project StORe: Social Science report

    OpenAIRE

    Burton, Guy

    2006-01-01

    There was widespread support across the social science research community regarding the aims of the StORe Project Nearly half of social science respondents claimed that both source-to-output and out-put-to source repositories would offer a ‘significant advantage to my work’; a third in both cases claimed it would be ‘useful but not of major significance’ Postgraduate students were generally more enthusiastic about source-to-output and output-to-source repositories than acade...

  7. AGING PERFORMANCE OF MODEL 9975 PACKAGE FLUOROELASTOMER O-RINGS

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E.; Daugherty, W.; Skidmore, E.; Dunn, K.; Fisher, D.

    2011-05-31

    The influence of temperature and radiation on Viton{reg_sign} GLT and GLT-S fluoroelastomer O-rings is an ongoing research focus at the Savannah River National Laboratory. The O-rings are credited for leaktight containment in the Model 9975 shipping package used for transportation of plutonium-bearing materials. At the Savannah River Site, the Model 9975 packages are being used for interim storage. Primary research efforts have focused on surveillance of O-rings from actual packages, leak testing of seals at bounding aging conditions and the effect of aging temperature on compression stress relaxation behavior, with the goal of service life prediction for long-term storage conditions. Recently, an additional effort to evaluate the effect of aging temperature on the oxidation of the materials has begun. Degradation in the mechanical properties of elastomers is directly related to the oxidation of the polymer. Sensitive measurements of the oxidation rate can be performed in a more timely manner than waiting for a measurable change in mechanical properties, especially at service temperatures. Measuring the oxidation rate therefore provides a means to validate the assumption that the degradation mechanisms(s) do not change from the elevated temperatures used for accelerated aging and the lower service temperatures. Monitoring the amount of oxygen uptake by the material over time at various temperatures can provide increased confidence in lifetime predictions. Preliminary oxygen consumption analysis of a Viton GLT-based fluoroelastomer compound (Parker V0835-75) using an Oxzilla II differential oxygen analyzer in the temperature range of 40-120 C was performed. Early data suggests oxygen consumption rates may level off within the first 100,000 hours (10-12 years) at 40 C and that sharp changes in the degradation mechanism (stress-relaxation) are not expected over the temperature range examined. This is consistent with the known long-term heat aging resistance of

  8. Special core analyses and relative permeability measurement on Almond formation reservoir rocks

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, D.; Doggett, K.; Brinkmeyer, A.

    1993-02-01

    This report describes the results from special core analyses and relative permeability measurements conducted on samples of rock from the Almond Formation in Greater Green River Basin of southwestern Wyoming. The core was from Arch Unit Well 121 of Patrick Draw field. Samples were taken from the 4,950 to 4,965 ft depth interval. Thin section evaluation, X-ray diffraction, routine permeability and porosity, capillary pressure and wettability tests were performed to characterize the samples. Fluid flow capacity characteristics were measured during two-phase unsteady- and steady-state and three-phase steady-state relative permeability tests. Test results are presented in tables and graphs. Relative permeability results are compared with those of a 260-mD, fired Berea sandstone sample which was previously subjected to similar tests. Brine relative permeabilities were similar for the two samples, whereas oil and gas relative permeabilities for the Almond formation rock were higher at equivalent saturation conditions compared to Berea results. Most of the tests described in this report were conducted at 74{degrees}F laboratory temperature. Additional tests are planned at 150{degrees}F temperature. Equipment and procedural modifications to perform the elevated temperature tests are described.

  9. Special core analyses and relative permeability measurement on Almond formation reservoir rocks

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, D.; Doggett, K.; Brinkmeyer, A.

    1993-02-01

    This report describes the results from special core analyses and relative permeability measurements conducted on samples of rock from the Almond Formation in Greater Green River Basin of southwestern Wyoming. The core was from Arch Unit Well 121 of Patrick Draw field. Samples were taken from the 4,950 to 4,965 ft depth interval. Thin section evaluation, X-ray diffraction, routine permeability and porosity, capillary pressure and wettability tests were performed to characterize the samples. Fluid flow capacity characteristics were measured during two-phase unsteady- and steady-state and three-phase steady-state relative permeability tests. Test results are presented in tables and graphs. Relative permeability results are compared with those of a 260-mD, fired Berea sandstone sample which was previously subjected to similar tests. Brine relative permeabilities were similar for the two samples, whereas oil and gas relative permeabilities for the Almond formation rock were higher at equivalent saturation conditions compared to Berea results. Most of the tests described in this report were conducted at 74[degrees]F laboratory temperature. Additional tests are planned at 150[degrees]F temperature. Equipment and procedural modifications to perform the elevated temperature tests are described.

  10. Mixed State and High Effective Utilization of Pilbara Blending Iron Ore Powder%Mixed State and High Effective Utilization of Pilbara Blending Iron Ore Powder

    Institute of Scientific and Technical Information of China (English)

    CAO Yong-guo; WU Sheng-li; HAN Hong-liang; WANG Hong-wei; XUE Fang; LIU Xiao-qin

    2011-01-01

    Pilbara blending iron ore powder (PB powder) is blending ores with good and poor quality iron ores, so how to use PB power effectively is a problem. The self-characteristics of PB powder and its single-components were studied respectively such as the macroscopic properties, microscopic properties, and high-temperature properties the behavior and effect in the sintering were mastered. Then based on the new ore-proportioning idea of iron ores sintering characteristics complementary, the principles on the effective use of PB powder were discussed, and was fur ther validated through the sintering pot test and industrial production. The results show that PB powder is composed of three kinds of iron ore, and the sintering characteristics of different iron ores are obviously discrepant. With the ore-proportioning optimization based on the iron ores sintering characteristics complementary, the proportion of PB iron ore powder can be increased to more than 45 %.

  11. Effect of the star formation histories on the SFR-M∗ relation at z ≥ 2

    Science.gov (United States)

    Cassarà, L. P.; Maccagni, D.; Garilli, B.; Scodeggio, M.; Thomas, R.; Le Fèvre, O.; Zamorani, G.; Schaerer, D.; Lemaux, B. C.; Cassata, P.; Le Brun, V.; Pentericci, L.; Tasca, L. A. M.; Vanzella, E.; Zucca, E.; Amorín, R.; Bardelli, S.; Castellano, M.; Cimatti, A.; Cucciati, O.; Durkalec, A.; Fontana, A.; Giavalisco, M.; Grazian, A.; Hathi, N. P.; Ilbert, O.; Paltani, S.; Ribeiro, B.; Sommariva, V.; Talia, M.; Tresse, L.; Vergani, D.; Capak, P.; Charlot, S.; Contini, T.; de la Torre, S.; Dunlop, J.; Fotopoulou, S.; Guaita, L.; Koekemoer, A.; López-Sanjuan, C.; Mellier, Y.; Pforr, J.; Salvato, M.; Scoville, N.; Taniguchi, Y.; Wang, P. W.

    2016-08-01

    We investigate the effect of different star formation histories (SFHs) on the relation between stellar mass (M∗) and star formation rate (SFR) using a sample of galaxies with reliable spectroscopic redshift zspec> 2 drawn from the VIMOS Ultra-Deep Survey (VUDS). We produce an extensive database of dusty model galaxies, calculated starting from a new library of single stellar population (SSPs) models, weighted by a set of 28 different star formation histories based on the Schmidt function, and characterized by different ratios of the gas infall timescale τinfall to the star formation efficiency ν. Dust extinction and re-emission were treated by means of the radiative transfer calculation. The spectral energy distribution (SED) fitting technique was performed by using GOSSIP+, a tool able to combine both photometric and spectroscopic information to extract the best value of the physical quantities of interest, and to consider the intergalactic medium (IGM) attenuation as a free parameter. We find that the main contribution to the scatter observed in the SFR-M∗ plane is the possibility of choosing between different families of SFHs in the SED fitting procedure, while the redshift range plays a minor role. The majority of the galaxies, at all cosmic times, are best fit by models with SFHs characterized by a high τinfall/ν ratio. We discuss the reliability of a low percentage of dusty and highly star-forming galaxies in the context of their detection in the far infrared (FIR).

  12. Exploring Systematic Effects in the Relation Between Stellar Mass, Gas Phase Metallicity, and Star Formation Rate

    CERN Document Server

    Telford, O Grace; Skillman, Evan D; Conroy, Charlie

    2016-01-01

    There is evidence that the well-established mass-metallicity relation in galaxies is correlated with a third parameter: star formation rate (SFR). The strength of this correlation may be used to disentangle the relative importance of different physical processes (e.g., infall of pristine gas, metal-enriched outflows) in governing chemical evolution. However, all three parameters are susceptible to biases that might affect the observed strength of the relation between them. We analyze possible sources of systematic error, including sample bias, application of S/N cuts on emission lines, choice of metallicity calibration, uncertainty in stellar mass determination, aperture effects, and dust. We present the first analysis of the relation between stellar mass, gas phase metallicity, and SFR using strong line abundance diagnostics from Dopita et al. (2013) for ~130,000 star-forming galaxies in the Sloan Digital Sky Survey and provide a detailed comparison of these diagnostics in an appendix. Using these abundance ...

  13. New Worlds Observer Formation Control Design Based on the Dynamics of Relative Motion

    Science.gov (United States)

    Luquette, Richard J.

    2008-01-01

    The New Worlds Observer (NWO) mission is designed for the direct detection and characterization of extrasolar planets. The NWO mission concept employs a two spacecraft leader-follower formation on a trajectory around the Earth/Moon-Sun L(sub 2) Libration Point. The leader spacecraft is baselined as a 4 meter optical telescope. The follower, Starshade spacecraft, is designed to suppress light from a central body star permitting direct detection of a surrounding exoplanetary system. The current design requires a nominal leader-follower separation range of 72 Megameters. NWO poses many challenges including formation control. NWO cycles between three principal control modes during the nominal mission timeline: science (fine pointing), realignment and transition. This paper examines formation control strategies in the context of dynamics of relative motion for two spacecraft operating in the vicinity of the Earth/Moon-Sun L(sub 2)libration point. The paper presents an overview of the equations of relative motion followed by a discussion of each of the control modes. Discussion and analysis characterize control strategies for each of the mission control modes, including requirements, implementation challenges and project fuel budgets.

  14. Synthesis of Fe-MCM-41 Using Iron Ore Tailings as the Silicon and Iron Source.

    Science.gov (United States)

    Li, Xin; Yu, Honghao; He, Yan; Xue, Xiangxin

    2012-01-01

    Highly ordered Fe-MCM-41 molecular sieve was successfully synthesized by using n-hexadecyl-trimethyl ammonium bromide (CTAB) as the template and the iron ore tailings (IOTs) as the silicon and iron source. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance UV-visible spectroscopy, (29)Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR), and nitrogen adsorption/desorption were used to characterize the samples. The results showed that the mesoporous materials had highly ordered 2-dimensional hexagonal structure. The synthesized sample had high surface area, and part of iron atoms is retained in the framework with formation of tetrahedron after removal of the template by calcinations. The results obtained in the present work demonstrate the feasibility of employing iron ore tailings as a potential source of silicon and iron to produce Fe-MCM-41 mesoporous materials.

  15. Iron ore pollution in Mandovi and Zuari estuarine sediments and its fate after mining ban.

    Science.gov (United States)

    Kessarkar, Pratima M; Suja, S; Sudheesh, V; Srivastava, Shubh; Rao, V Purnachandra

    2015-09-01

    Iron ore was mined from the banded iron formations of Goa, India, and transported through the Mandovi and Zuari estuaries for six decades until the ban on mining from September 2012. Here we focus on the environmental magnetic properties of sediments from the catchment area, upstream and downstream of these estuaries, and adjacent shelf during peak mining time. Magnetic susceptibility (χ lf) and saturation isothermal remanent magnetization (SIRM) values of sediments were highest in upstream (catchment area and estuaries), decreased gradually towards downstream (catchment area and estuaries), and were lowest on the adjacent shelf. The χ lf values of the Mandovi estuary were two to fourfold higher than those in the Zuari. The sediments of these two estuaries after the mining ban showed enrichment of older magnetite and sharp decrease in the SIRM values. Although the input of ore material has been reduced after mining ban, more flushing of estuarine sediments is required for healthier environment.

  16. Synthesis of Fe-MCM-41 Using Iron Ore Tailings as the Silicon and Iron Source

    Directory of Open Access Journals (Sweden)

    Xin Li

    2012-01-01

    Full Text Available Highly ordered Fe-MCM-41 molecular sieve was successfully synthesized by using n-hexadecyl-trimethyl ammonium bromide (CTAB as the template and the iron ore tailings (IOTs as the silicon and iron source. X-ray diffraction (XRD, high-resolution transmission electron microscopy (HRTEM, diffuse reflectance UV-visible spectroscopy, 29Si magic-angle spinning (MAS nuclear magnetic resonance (NMR, and nitrogen adsorption/desorption were used to characterize the samples. The results showed that the mesoporous materials had highly ordered 2-dimensional hexagonal structure. The synthesized sample had high surface area, and part of iron atoms is retained in the framework with formation of tetrahedron after removal of the template by calcinations. The results obtained in the present work demonstrate the feasibility of employing iron ore tailings as a potential source of silicon and iron to produce Fe-MCM-41 mesoporous materials.

  17. Thermochemical sulphate reduction and Huayuan lead-zinc ore deposit in Hunan, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In recent years, some arguments with regard to the organicmineralization of MVT lead-zinc ore deposit are focused on the thermochemical sulphate reduction in the presence of organic matter. Based on the research into the organic geochemistry and C, O, S isotopes of mineralized host rocks, mineral gas fluid inclusion and solid bitumen from Huayuan (W. Hunan, China) lead-zinc ore deposit formed in the algal limestones of Qingxudong formation, Lower Cambrian, the authors consider that a lot of organic matter occurred and participated in mineralization. The organic matter from different sources participated in the mineralization with two main forms: thermochemical sul-phate reduction and thermal degradation which supplied abundant H2S for the precipitation.

  18. Chalcophile element (Ni, Cu, PGE, and Au) variations in the Tamarack magmatic sulfide deposit in the Midcontinent Rift System: implications for dynamic ore-forming processes

    Science.gov (United States)

    Taranovic, Valentina; Ripley, Edward M.; Li, Chusi; Rossell, Dean

    2016-10-01

    correlation between Pt and Pd, and between individual IPGE. At a given Pt or Pd content, however, the semi-massive sulfide ores have higher IPGE contents than the disseminated sulfide samples. Modeling results show that the variations in PGE tenors (metals in recalculated 100 % sulfide) in the Tamarack magmatic sulfide deposit are mainly controlled by variable R factors (magma/sulfide-liquid mass ratios) during sulfide-liquid segregation and subsequent monosulfide solid solution (MSS) fractionation during cooling. The initial contents of Ir, Pt, and Pd in the parental magma, estimated from the metal tenors of the disseminated sulfides, are 0.2, 2, and 1.8 ppb, respectively, which are ˜1/5 of the values for the PGE-undepleted primitive basalts of the Midcontinent Rift System. The variations of PGE tenors in the semi-massive and massive sulfide ores can be explained by MSS fractional crystallization from sulfide liquids. Extreme variations in the PGE contents of the massive sulfides may also in part reflect metal mobility during post-crystallization hydrothermal processes. The higher PGE tenors for the disseminated sulfides in the CGO dike relative to those in the FGO Intrusion are consistent with formation in a dynamic conduit where the early sulfide liquids left in the conduit by the FGO magma were subsequently upgraded by the subsequent surge of the CGO magma. The relatively low PGE tenors for the semi-massive and massive sulfides can be explained by lack of such an upgrading process for the sulfide due to their distal locations in a migrating conduit.

  19. The Relation between Luminous AGNs and Star Formation in Their Host Galaxies

    Science.gov (United States)

    Xu, Lei; Rieke, G. H.; Egami, E.; Haines, C. P.; Pereira, M. J.; Smith, G. P.

    2015-08-01

    We study the relation of active galactic nuclei (AGNs) to star formation in their host galaxies. Our sample includes 205 Type-1 and 85 Type-2 AGNs, 162 detected with Herschel, from fields surrounding 30 galaxy clusters in the Local Cluster Substructure Survey. The sample is identified by optical line widths and ratios after selection to be brighter than 1 mJy at 24 μm. We show that Type-2 AGN [O iii]λ5007 line fluxes at high z can be contaminated by their host galaxies with typical spectrograph entrance apertures (but our sample is not compromised in this way). We use spectral energy distribution (SED) templates to decompose the galaxy SEDs and estimate star formation rates (SFRs), AGN luminosities, and host galaxy stellar masses (described in an accompanying paper). The AGNs arise from massive black holes (˜ 3× {10}8{M}⊙ ) accreting at ˜10% of the Eddington rate and residing in galaxies with stellar mass \\gt 3× {10}10{M}⊙ ; those detected with Herschel have IR luminosity from star formation in the range of {L}{SF,{IR}}˜ {10}10-{10}12{L}⊙ . We find that (1) the specific SFRs in the host galaxies are generally consistent with those of normal star-forming (main sequence) galaxies; (2) there is a strong correlation between the luminosities from star formation and the AGN; and (3) the correlation may not result from a causal connection, but could arise because the black hole mass (and hence AGN Eddington luminosity) and star formation are both correlated with the galaxy mass.

  20. The resolved star-formation relation in nearby active galactic nuclei

    CERN Document Server

    Casasola, Viviana; Combes, Francoise; Garcia-Burillo, Santiago

    2015-01-01

    We present an analysis of the relation between star formation rate (SFR) surface density (sigmasfr) and mass surface density of molecular gas (sigmahtwo), commonly referred to as the Kennicutt-Schmidt (K-S) relation, at its intrinsic spatial scale, i.e. the size of giant molecular clouds (10-150 pc), in the central, high-density regions of four nearby low-luminosity active galactic nuclei (AGN). We used interferometric IRAM CO(1-0) and CO(2-1), and SMA CO(3-2) emission line maps to derive sigmahtwo and HST-Halpha images to estimate sigmasfr. Each galaxy is characterized by a distinct molecular SF relation at spatial scales between 20 to 200 pc. The K-S relations can be sub-linear, but also super-linear, with slopes ranging from 0.5 to 1.3. Depletion times range from 1 and 2Gyr, compatible with results for nearby normal galaxies. These findings are valid independently of which transition, CO(1-0), CO(2-1), or CO(3-2), is used to derive sigmahtwo. Because of star-formation feedback, life-time of clouds, turbule...

  1. [The effect of impression formation on memory of trait words: relation between coding and retrieval process].

    Science.gov (United States)

    Takaoka, M

    2000-08-01

    Three experiments investigated the effect of impression formation of a person on the recall and recognition of trait words. The subjects were assigned to one of four groups: Impression, Memory, Impression-Memory, and Incidental groups. Each subject performed an orienting task followed by free recall and recognition tests. In a recall test, false recall of antonyms of targets occurred more often in the Memory group than in the Impression group. There was no difference in the correct recall. In a multiple choice recognition test and a yes-no recognition test, false recognition to antonyms of targets occurred more often in the Memory group than in the Impression group. Hit to targets occurred more often in the Impression group than in the Memory group. These results were interpreted as showing that formation of an impression for a person had different effects for recall and recognition tests. The results were discussed in terms of a relation between encoding and retrieval processes.

  2. Spacecraft Formation Control: Managing Line-of-Sight Drift Based on the Dynamics of Relative Motion

    Science.gov (United States)

    Luquette, Richard J.; Sammer. Robert M.

    2008-01-01

    In a quest to improve space-based observational capability, an increasing number of investigators are proposing missions with precision formation flying architectures. Typical missions include the Micro- Arcsecond X-ray Imaging Mission (MAXIM), Stellar Imager (SI), and the New Worlds Observer (NWO). Missions designed to explore targets in deep-space generally require holding a formation configuration fixed in inertial space during science observation. Analysis in this paper is specifically aimed at the NWO architecture, characterizing the natural drift of the line-of-sight and the separation range for two spacecraft operating in the vicinity of the Earth/Moon-Sun L(sub 2) libration point. Analysis employs a linear form of the relative dynamics associated with an n-body gravity field. The study is designed to identify favorable observation directions, characterized by minimal line-of-sight drift, along the mission timeline.

  3. Fluid mechanics simulation of fog formation associated with polluted atmosphere produced by energy related fuel combustion

    Science.gov (United States)

    Hung, R. J.; Liaw, G. S.

    1980-01-01

    It is noted that large quantities of atmospheric aerosols with composition SO4(-2), NO3(-1), and NH4(+1) have been detected in highly industrialized areas. Most aerosol products come from energy-related fuel combustion. Fluid mechanics simulation of both microphysical and macrophysical processes is considered in studying the time dependent evolution of the saturation spectra of condensation nuclei associated with polluted and clean atmospheres during the time periods of advection fog formation. The results demonstrate that the condensation nuclei associated with a polluted atmosphere provide more favorable conditions than condensation nuclei associated with a clean atmosphere to produce dense advection fog, and that attaining a certain degree of supersaturation is not necessarily required for the formation of advection fog having condensation nuclei associated with a polluted atmosphere.

  4. Relative position coordinated control for spacecraft formation flying with communication delays

    Science.gov (United States)

    Ran, Dechao; Chen, Xiaoqian; Misra, Arun K.; Xiao, Bing

    2017-08-01

    This study addresses a relative position coordinated control problem for spacecraft formation flying subject to directed communication topology. Two different kinds of communication delay cases, including time-varying delays and arbitrarily bounded delays are investigated. Using the backstepping control technique, two virtual velocity control inputs are firstly designed to achieve coordinated position tracking for the kinematic subsystem. Furthermore, a hyperbolic tangent function is introduced to guarantee the boundedness of the virtual controller. Then, a finite-time control algorithm is designed for the dynamic subsystem. It can guarantee that the virtual velocity can be followed by the real velocity after finite time. It is theoretically proved that the proposed control scheme can asymptotically stabilize the closed-loop system. Numerical simulations are further presented that not only highlight closed-loop performance benefiting from the proposed control scheme, but also illustrate its superiority in comparison with conventional formation control schemes.

  5. Properties of the Medussae Fossae Formation and its relation to the volcanic history of Mars

    Science.gov (United States)

    Ivanov, Anton B.; Cantini, Federico

    2016-10-01

    Medussae Fossae (MFF) is a well known formation, stretching west of Tharsis volanoes. It is characterized as a relatively young Amazonian units (Amm, Amu), due to widespread signs of erosion. Earth based imaging radar observations at 3.5 cm [1] and 12 cm [2] have discovered a dark radar feature (Stealth), which roughly correlates with the MFF outline.Recent investigations [3], suggested that the unit emplacement is in fact during Hesperian period, but it is composed of material that can be easily eroded. It is not clear when the erosion happened and if it is a continuing process. Hypotheses on MFF formation range from volcanic material emplacement (ash flow tuffs or pyroclastic materials) to an ice-rich dusty mantle, deposited during high obliquity.In this work, we will present the latest observations of the East Medussae Fossae formation by the long wavelength MARSIS radar, continuing the work reported in [4], as well as complementing data surveyed by SHARAD data in [5]. The MARSIS radar has detected strong subsurface interfaces in the areas of Gordi and Eumenides Dorsae at depths up to 1.5km. We will present our analysis of the data, inferring the dielectric properties of the material to constrain properties of the material constituting the Medusae Fossae formation. We will also demonstrate an efficient user interface to work with MARSIS data inside a Geographical Information System (GIS).The research leading to these results has received funding from the European Unions Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement 607379.[1] D. Muhleman, et al., "Radar images of mars," Science, vol. 253, no. 5027, 1991.[2] J. K. Harmon, et al., "Arecibo radar imagery of Mars: The major volcanic provinces," Icarus, vol. 220, aug 2012.[3] L. Kerber, et al., "The dispersal of pyroclasts from Apollinaris Patera, Mars: Implications for the origin of the Medusae Fossae Formation," Icarus, vol. 216, nov 2011.[4] T. R. Watters, et al., "Radar Sounding of the

  6. XPS and FTIR spectroscopic study on microwave treated high phosphorus iron ore

    Energy Technology Data Exchange (ETDEWEB)

    Omran, Mamdouh, E-mail: mamdouh.omran@oulu.fi [Process Metallurgy Research Group, Faculty of Technology, University of Oulu (Finland); Mineral Processing and Agglomeration Lab, Central Metallurgical Research and Development Institute, Cairo (Egypt); Fabritius, Timo [Process Metallurgy Research Group, Faculty of Technology, University of Oulu (Finland); Elmahdy, Ahmed M.; Abdel-Khalek, Nagui A. [Mineral Processing and Agglomeration Lab, Central Metallurgical Research and Development Institute, Cairo (Egypt); El-Aref, Mortada; Elmanawi, Abd El-Hamid [Geology Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2015-08-01

    Highlights: • The effect of microwave radiation on structure and chemical state of high phosphorus iron ore was studied. • FTIR analyses showed that after microwave radiation the functional chemical groups of phosphorus bearing minerals (fluorapatite) dissociated. • High resolution XPS analyses of Fe 2p peaks showed that after microwave radiation a portion of Fe(+III) was reduced to Fe(+II). • Microwave radiation had a positive effect on the magnetic properties of iron oxide, through formation of ferromagnetic phases. - Abstract: A growing interest in microwave heating has emerged recently. Several potential microwave applications regarding minerals’ processing have been investigated. This paper investigates the effect of microwave radiation on Egyptian high phosphorus iron ore. Three different iron ore samples have varying Fe{sub 2}O{sub 3} and P{sub 2}O{sub 5} contents and mineralogical textures were studied. A comparative study has been carried out between untreated and microwave treated iron ore. XRD and FTIR analyses showed that after microwave radiation the crystallinity of iron bearing minerals (hematite) increased, while the functional chemical groups of phosphorus bearing minerals (fluorapatite) and other gangues dissociated. High resolution XPS analyses of Fe 2p peaks showed that after microwave radiation a portion of Fe(+III) was reduced to Fe(+II). This means that after microwave radiation iron oxide (hematite, Fe{sup 3+}) transformed into more magnetic phase. The results indicated that microwave radiation had a positive effect on the magnetic properties of iron oxide, through formation of ferromagnetic phases.

  7. Compositional variation of glauconites in Upper Cretaceous-Paleogene sedimentary iron-ore deposits in South-eastern Western Siberia

    Science.gov (United States)

    Rudmin, Maxim; Banerjee, Santanu; Mazurov, Aleksey

    2017-06-01

    Glauconite occurs either as unaltered greenish or as altered brownish variety in Upper Cretaceous-Palaeocene sediments in the southeastern corner of Western Siberia. Studied section within the Bakchar iron-ore deposit includes Ipatovo, Slavgorod, Gan'kino and Lyulinvor formations, which are represented by sandstones, siltstones, claystones and oolitic ironstones of coastal-marine facies. The origin of unaltered glauconite is explained by the ;verdissement theory;. Transgressions during Lower Coniacian, Santonian and Campanian favored the formation of unaltered glauconites in dysoxic to anoxic conditions. Subaerial exposure of glauconite resulted in leaching of potassium, oxidation of iron and formation of iron hydroxides in Upper Coniacian, Maastrichtian and Palaeocene. Glauconite ultimately converts to leptochlorite and hydrogoethite by this alteration. Abundant microscopic gold inclusions, besides sulphides, sulphates, oxides and silicates characterize this glauconite. Mineral inclusions include precious, rare metals and non-ferrous metals. The concentration of gold in glauconite may be as high as 42.9 ppb. Abundant inclusions of various compositions in glauconites indicate enrichment of marine sediments in precious and non-precious metals. While major element composition of glauconites is affected by subaerial exposure, the broadly similar micro-inclusions in both altered and unaltered varieties are possibly related to the comparatively immobile nature of REE and trace elements.

  8. The Scaling Relations and Star Formation Laws of Mini-starburst Complexes

    Science.gov (United States)

    Nguyen-Luong, Quang; Nguyen, Hans V. V.; Motte, Fredérique; Schneider, Nicola; Fujii, Michiko; Louvet, Fabien; Hill, Tracey; Sanhueza, Patricio; Chibueze, James O.; Didelon, Pierre

    2016-12-01

    The scaling relations and star formation laws for molecular cloud complexes (MCCs) in the Milky Way are investigated. MCCs are mostly large (R > 50 pc), massive (˜106 {\\text{}}{M}⊙ ) gravitationally unbound cloud structures. We compare their masses {M}{gas}, mass surface densities {{{Σ }}}{M{gas}}, radii R, velocity dispersions σ, star formation rates (SFRs), and SFR densities {{{Σ }}}{SFR} with those of structures ranging from cores, clumps, and giant molecular clouds, to MCCs, and galaxies, spanning eight orders of magnitudes in size and 13 orders of magnitudes in mass. This results in the following universal relations:σ ˜ {R}0.5,{M}{gas}˜ {R}2,{{{Σ }}}{SFR}˜ {{{Σ }}}{M{gas}}1.5, {SFR}˜ {{M}{gas}}0.9, {and} {SFR}˜ {σ }2.7. Variations in the slopes and coefficients of these relations are found at individual scales, signifying different physics acting at different scales. Additionally, there are breaks at the MCC scale in the σ {--}R relation and between starburst and normal star-forming objects in the {SFR}{--}{M}{gas} and {{{Σ }}}{SFR}-{{{Σ }}}{{{M}}{gas}} relations. Therefore, we propose to use the Schmidt-Kennicutt diagram to distinguish starburst from normal star-forming structures by applying a {{{Σ }}}{M{gas}} threshold of ˜100 {\\text{}}{M}⊙ pc-2 and a {{{Σ }}}{SFR} threshold of 1 {\\text{}}{M}⊙ yr-1 kpc-2. Mini-starburst complexes are gravitationally unbound MCCs that have enhanced {{{Σ }}}{SFR} (>1 {\\text{}}{M}⊙ yr-1 kpc-2), probably caused by dynamic events such as radiation pressure, colliding flows, or spiral arm gravitational instability. Because of dynamical evolution, gravitational boundedness does not play a significant role in regulating the star formation activity of MCCs, especially the mini-starburst complexes, which leads to the dynamical formation of massive stars and clusters. We emphasize the importance of understanding mini-starbursts in investigating the physics of starburst galaxies.

  9. Aging Behavior of the EPDM O-Rings in the H1616 Shipping Package

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W.; Stefek, T.; Skidmore, E.

    2015-06-09

    The H1616 shipping package is used within the DOE complex for shipping tritium reservoirs. The annual recertification frequency can create logistical difficulties with other constraints on the timing of shipments; thus, a longer re-certification period is desirable. The ethylene propylene diene monomer (EPDM) O-rings used in the H1616 shipping package are being aged and tested at the Savannah River National Laboratory (SRNL) to provide a technical basis for extending the annual maintenance of the H1616 shipping package. H1616 EPDM O-rings are being aged at elevated temperature, and tested for degradation in mechanical properties, compression stress relaxation (CSR) behavior, and leak performance. Mechanical properties of aged O-rings show significant degradation can occur, but an inert atmosphere (argon backfill) greatly reduces the rate of degradation. The CSR behavior of O-rings was evaluated in air at 79 to 177 °C. These collective data were used to develop a predictive model for extrapolation of CSR behavior to relevant service temperatures (<67 °C). O-rings were also aged in H1616 Containment Vessels (CV) in an inert atmosphere at 71 to 149 °C. The vessels are helium leak tested periodically to determine if they continue to remain leak-tight. The vessel tests provide a solid demonstration that the H1616 O-rings will remain leak-tight at temperatures up to 113 °C for up to approximately 2.3 years. Significantly longer periods of leak-tight service are expected at the lower temperatures actually experienced in service. The predictive model developed from the CSR data conservatively indicates a service life of ~5 years at 67 °C. Although the relationship between CSR behavior and leak-tight performance has not been established for this design, the CSR predictions for this O-ring are conservative relative to leak-tight performance. Based on the collective data developed to date, SRNL has recommended that the maintenance interval for the H1616 package be

  10. Algal—Bacterial Fabrics of Ores and Their Genetic Implications in the Longtang Lead—Zinc Deposit at Yanbian,Sichuan

    Institute of Scientific and Technical Information of China (English)

    帅德权; 张寿庭; 等

    1995-01-01

    The Longtang Pb-Zn deposit occurs in the Upper Sinian Guanyinyan For-mation.The host rocks include sandy shale,cherty limestone and dolomitic limestone.The deposit is a typical one of thallogen origin.The mineral assemblage in the ore is made up of sphalerite, galena, pyrite, enargite, tennantite, seligmannite, asphalt, etc.The ore-forming process is possessed of multi-episode and multi-stage characters. Generally, sphalerites exhibit algal stromatolitic, bac-terial and algal colloidal textures, providing evidence for the direct involvement of alage and bacteria in mineralization of ore-forming elements during sedimentary diagenesis. This is the first transmigration of ore-forming elements.However, pyrite embracing bac-teria and galena replacing/filling trichomes are typical organic textures, which are related to organic carbon and bitumen that can adsorb or reduce ore-forming elements. This is an indirect process of organic mineralization ,ie.,the second transmigration of ore-forming elements.&34S values are all greater than 5%o,indicating the dominance of the heavy sulfur isotopes.The ore-forming temperature deduced from fluid inclusions ranges from 100℃to 150℃±.All this goes to show that the Longtang Pb-Zn deposit is of thallogen origin.

  11. Exploring the Role of Galaxy Morphology in the Mass-Metallicity-Star Formation Rate Relation

    Science.gov (United States)

    Pahl, Anthony; Rafelski, Marc; Scarlata, Claudia; Pacifici, Camilla; Henry, Alaina L.; Gardner, Jonathan P.; Elmegreen, Debra M.

    2017-01-01

    The Mass-Metallicity-Star Formation Rate (M-Z-SFR) fundamental relation reveals the underlying physics behind galaxy evolution: the mechanics of gas inflow, outflow, and the formation of stars are intimately connected. At higher redshift, we observe galaxies which are believed to be more actively accreting from the cosmic web, and as a result bright star-forming clumps are expected to form due to the increased gravitational instability of the galactic medium. We investigate these “clumpy” galaxies in context of their location on the M-Z-SFR plane to search for evidence of metal-poor gas inflows as predicted by theoretical models, and to help us understand how galaxies form and change at a higher redshift (1.3 fundamental plane to investigate possible diminished metallicity and heightened star formation rate compared to the remainder of the sample. This will enable us to better understand the theoretical underpinnings of gas accretion and galaxy evolution at high redshift.

  12. Seasonal development of cambial activity in relation to xylem formation in Chinese fir.

    Science.gov (United States)

    Wu, Hongyang; Xu, Huimin; Li, Hanyin; Wei, Dongmei; Lin, Jinxing; Li, Xiaojuan

    2016-05-20

    The vascular cambium is a lateral meristem which can differentiate into secondary phloem and xylem. The secondary growth of woody plants resulting from vascular cambium activity has been a focus of considerable attention, but the quantitative relationships between cambial activity and secondary xylem formation have been little studied. Our analysis of cytological changes in the cambium of Chinese fir (Cunninghamia lanceolata), revealed a significant positive correlation between vascular cambium cell numbers and cambium zone width through the seasonal cycle. Cambium cell numbers and the cambium cell radial diameter were closely related to xylem formation. Immuno-labeling showed that de-esterified homogalacturonan and (1-4)-β-d-galactan epitopes were highly abundant in cell walls of dormant-stage cambium, whereas high methylesterified homogalacturonan was strongly labeled in the active stage. Raman spectroscopy detected significant changes in the chemical composition of cell walls during the active-dormant stage transition. More pectin and less monolignols occurred in radial cell walls than in tangential walls during the dormant stage, but no significant changes were found in other stages, indicating that pectin accumulation facilitates cell wall expansion, with cambium activity transition. Our quantitative analysis of the relationship between cambial activity and xylem formation, as well as the cell wall modification during the active stage provides useful information about cambial characteristics and xylogenesis. Copyright © 2016. Published by Elsevier GmbH.

  13. The Relation between Luminous AGNs and Star Formation in Their Host Galaxies

    CERN Document Server

    Xu, Lei; Egami, E; Haines, C P; Pereira, M J; Smith, G P

    2015-01-01

    We study the relation of active galactic nuclei (AGNs) to star formation in their host galaxies. Our sample includes 205 Type-1 and 85 Type-2 AGNs, 162 detected with Herschel, from fields surrounding 30 galaxy clusters in the Local Cluster Substructure Survey (LoCuSS). The sample is identified by optical line widths and ratios after selection to be brighter than 1 mJy at 24 microns. We show that Type-2 AGN [OIII]5007 line fluxes at high z can be contaminated by their host galaxies with typical spectrograph entrance apertures (but our sample is not compromised in this way). We use spectral energy distribution (SED) templates to decompose the galaxy SEDs and estimate star formation rates, AGN luminosities, and host galaxy stellar masses (described in an accompanying paper). The AGNs arise from massive black holes (~ 3 X 10^8 Msun) accreting at ~ 10% of the Eddington rate and residing in galaxies with stellar mass > 3 X 10^{10} Msun; those detected with Herschel have IR luminosity from star formation in the rang...

  14. Pitfalls when observationally characterizing the relative formation rates of stars and stellar clusters in galaxies

    Science.gov (United States)

    Kruijssen, J. M. Diederik; Bastian, Nate

    2016-03-01

    Stars generally form in aggregates, some of which are bound (`clusters') while others are unbound and disperse on short ({˜ }10 { Myr}) time-scales (`associations'). The fraction of stars forming in bound clusters (Γ) is a fundamental outcome of the star formation process. Recent observational and theoretical work has suggested that Γ increases with the gas surface density (Σ) or star formation rate (SFR) surface density (ΣSFR), both within galaxies and between different ones. However, a recent paper by Chandar et al. has challenged these results, showing that the total number of stellar aggregates per unit SFR does not vary systematically with the host galaxy's absolute SFR. In this Letter, we show that no variations are expected when no distinction is made between bound and unbound aggregates, because the sum of these two fractions should be close to unity. We also demonstrate that any scaling of Γ with the absolute SFR is much weaker than with ΣSFR, due to the mass-radius-SFR relation of star-forming `main-sequence' galaxies. The environmental variation of Γ should therefore be probed as a function of area-normalized quantities, such as Σ or ΣSFR. We present a set of guidelines for meaningful observational tests of cluster formation theories and show that these resolve the reported discrepancy.

  15. High-temperature performance prediction of iron ore fines and the ore-blending programming problem in sintering

    Institute of Scientific and Technical Information of China (English)

    Bing-ji Yan; Jian-liang Zhang; Hong-wei Guo; Ling-kun Chen; Wei Li

    2014-01-01

    The high-temperature performance of iron ore fines is an important factor in optimizing ore blending in sintering. However, the application of linear regression analysis and the linear combination method in most other studies always leads to a large deviation from the desired results. In this study, the fuzzy membership functions of the assimilation ability temperature and the liquid fluidity were proposed based on the fuzzy mathematics theory to construct a model for predicting the high-temperature performance of mixed iron ore. Comparisons of the prediction model and experimental results were presented. The results illustrate that the prediction model is more accurate and effec-tive than previously developed models. In addition, fuzzy constraints for the high-temperature performance of iron ore in this research make the results of ore blending more comparable. A solution for the quantitative calculation as well as the programming of fuzzy constraints is also introduced.

  16. Relative navigation for autonomous formation flying satellites using the state-dependent Riccati equation filter

    Science.gov (United States)

    Park, Han-Earl; Kim, Young-Rok

    2016-01-01

    A relative navigation method for autonomous formation flying using the state-dependent Riccati equation filter (SDREF) is presented. In the SDREF, nonlinear relative dynamics, including J2 perturbation, are parameterized into a state-dependent coefficient (SDC) form without any loss of nonlinearity. The relative navigation algorithm is established based on the carrier-phase differential GPS (CDGPS) and single-frequency GPS data, in which the SDREF is used as a nonlinear estimator. To evaluate the SDREF performance, two different extended Kalman filters (EKFR1 and EKFR2) are introduced. The dynamic models of all the filters are based on relative motion including J2 perturbation. However, the SDREF and the EKFR1 use linear state propagation, whereas EKFR2 employs nonlinear state propagation. The navigation simulation is performed for each filter using live GPS signals simulated by a GPS signal generator, and the result is analyzed in terms of estimation accuracy and computational load. As a result, the SDREF provides a relative navigation solution with 3-D RMS accuracies of 6.0 mm and 0.153 mm/s for position and velocity, respectively, for a separation of 50 km with a computation time of approximately 34 s. The simulation results demonstrate that the SDREF estimates the relative states as rapidly as the EKFR1 and as accurately as the EKFR2, which means that the developed SDREF combines the strong points of EKFR1 and EKFR2 and overcomes their disadvantages.

  17. THE RELATION BETWEEN COOL CLUSTER CORES AND HERSCHEL-DETECTED STAR FORMATION IN BRIGHTEST CLUSTER GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Rawle, T. D.; Egami, E.; Rex, M.; Fiedler, A.; Haines, C. P.; Pereira, M. J.; Portouw, J.; Walth, G. [Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Edge, A. C. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Smith, G. P. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Altieri, B.; Valtchanov, I. [Herschel Science Centre, ESAC, ESA, P.O. Box 78, Villanueva de la Canada, 28691 Madrid (Spain); Perez-Gonzalez, P. G. [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Van der Werf, P. P. [Sterrewacht Leiden, Leiden University, P.O. Box 9513, 2300 RA, Leiden (Netherlands); Zemcov, M., E-mail: trawle@as.arizona.edu [Department of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-03-01

    We present far-infrared (FIR) analysis of 68 brightest cluster galaxies (BCGs) at 0.08 < z < 1.0. Deriving total infrared luminosities directly from Spitzer and Herschel photometry spanning the peak of the dust component (24-500 {mu}m), we calculate the obscured star formation rate (SFR). 22{sup +6.2}{sub -5.3}% of the BCGs are detected in the far-infrared, with SFR = 1-150 M{sub Sun} yr{sup -1}. The infrared luminosity is highly correlated with cluster X-ray gas cooling times for cool-core clusters (gas cooling time <1 Gyr), strongly suggesting that the star formation in these BCGs is influenced by the cluster-scale cooling process. The occurrence of the molecular gas tracing H{alpha} emission is also correlated with obscured star formation. For all but the most luminous BCGs (L{sub TIR} > 2 Multiplication-Sign 10{sup 11} L{sub Sun }), only a small ({approx}<0.4 mag) reddening correction is required for SFR(H{alpha}) to agree with SFR{sub FIR}. The relatively low H{alpha} extinction (dust obscuration), compared to values reported for the general star-forming population, lends further weight to an alternate (external) origin for the cold gas. Finally, we use a stacking analysis of non-cool-core clusters to show that the majority of the fuel for star formation in the FIR-bright BCGs is unlikely to originate from normal stellar mass loss.

  18. Dwarf galaxies with ionizing radiation feedback. II. Spatially resolved star formation relation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-hoon; Krumholz, Mark R.; Wise, John H.; Turk, Matthew J.; Goldbaum, Nathan J.; Abel, Tom

    2013-11-15

    AWe investigate the spatially resolved star formation relation using a galactic disk formed in a comprehensive high-resolution (3.8 pc) simulation. Our new implementation of stellar feedback includes ionizing radiation as well as supernova explosions, and we handle ionizing radiation by solving the radiative transfer equation rather than by a subgrid model. Photoheating by stellar radiation stabilizes gas against Jeans fragmentation, reducing the star formation rate (SFR). Because we have self-consistently calculated the location of ionized gas, we are able to make simulated, spatially resolved observations of star formation tracers, such as Hα emission. We can also observe how stellar feedback manifests itself in the correlation between ionized and molecular gas. Applying our techniques to the disk in a galactic halo of 2.3 × 1011 M , we find that the correlation between SFR density (estimated from mock Hα emission) and H2 density shows large scatter, especially at high resolutions of ≲ 75 pc that are comparable to the size of giant molecular clouds (GMCs). This is because an aperture of GMC size captures only particular stages of GMC evolution and because Hα traces hot gas around star-forming regions and is displaced from the H2 peaks themselves. By examining the evolving environment around star clusters, we speculate that the breakdown of the traditional star formation laws of the Kennicutt-Schmidt type at small scales is further aided by a combination of stars drifting from their birthplaces and molecular clouds being dispersed via stellar feedback.

  19. Genetic Pd, Pt, Au, Ag, and Rh mineralogy in Noril'sk sulfide ores

    Science.gov (United States)

    Spiridonov, E. M.; Kulagov, E. A.; Serova, A. A.; Kulikova, I. M.; Korotaeva, N. N.; Sereda, E. V.; Tushentsova, I. N.; Belyakov, S. N.; Zhukov, N. N.

    2015-09-01

    The undeformed ore-bearing intrusions of the Noril'sk ore field (NOF) cut through volcanic rocks of the Late Permian-Early Triassic trap association folded in brachysynclines. Due to the nonuniform load on the roof of intrusive bodies, most sulfide melts were squeezed, up to the tops of ore-bearing intrusions; readily fusible Ni-Fe-Cu sulfide melts were almost completely squeezed. In our opinion, not only one but two stages of mineralization developed at the Noril'sk deposits: (i) syntrap magmatic and (ii) epigenetic post-trap metamorphic-hydrothermal. All platinum-group minerals (PGM) and minerals of gold are metasomatic in the Noril'sk ores. They replaced sulfide solid solutions and exsolution structures. All types of PGM and Au minerals occur in the ores, varying in composition from pyrrhotite to chalcopyrite, talnakhite, mooihoekite, and rich in galena; they are localized in the inner and outer contact zones and differ only in the quantitative proportions of ore minerals. The aureoles of PGM and Au-Ag minerals are wider than the contours of sulfide bodies and coincide with halos of fluid impact on orebodies and adjacent host rocks. The pneumatolytic PGM and Au-Ag minerals are correlated in abundance with the dimensions of sulfide bodies. Their amounts are maximal in veins of late fusible ore composed of eutectic PbS ss and iss intergrowths, as well as at their contacts. The Pd and Pt contents in eutectic sulfide ores of NOF are the world's highest. In the process of noble-metal mineral formation, the fluids supply Pd, Pt, Au, As, Sb, Sn, Bi, and a part of Te, whereas Fe, Ni, Cu, Pb, Ag, Rh, a part of Te and Pd are leached from the replaced sulfide minerals. The pneumatolytic PGM of the early stage comprises Pd and Pt intermetallic compounds enriched in Au along with Pd-Pt-Fe-Ni-Cu-Sn-Pb(As) and (Pd,Pt,Au)(Sn,Sb,Bi,Te,As) solid solutions. Pneumatolytic PGM and Au minerals of the middle stage are products of solid-phase transformation and recrystallization of

  20. SIMS measurements of δ 34S in sulfide minerals from adjacent vein and stratabound ores

    Science.gov (United States)

    Macfarlane, Andrew W.; Shimizu, Nobumichi

    1991-02-01

    The effects of sample matrix and secondary ion energy on the instrumental fractionation of sulfur isotopes have been studied for troilite, pyrite, and galena using the Cameca IMS-3f ion microprobe. An analytical procedure is described for the measurement of δ 34S on negatively charged sulfur ions from pyrite and galena with a reproducibility better than ±1.5%. Sulfur isotope ratios were measured in pyrite and galena from adjacent stratabound manto orebodies and crosscutting veins in the Hualgayoc district of northern Peru. Isotopic compositions (δ 34S CDT) of sulfur in pyrite and galena from vein and manto deposits have a total range from -20 to 10%.. Sulfur in manto galenas has a wide range of isotopic compositions and is usually isotopically heavier than pyrite when both minerals have been analyzed in the same sample. Isotopic disequilibrium between pyrite and galena suggests precipitation from separate fluids, consistent with textural evidence that galena is paragenetically later than pyrite and often replaces it. Formation of ore minerals in the veins appears to have overlapped temporally with the later stages of manto mineralization and continued after manto formation ceased. Sulfur isotope values in pyrite and galena from veins are lower by about 5%. on average than the same sulfides in the mantos, and δ 34S values of vein galenas decrease over the course of vein formation. This shift of δ 34S toward lower values with time may be the result of increased mixing with sulfur from diagenetic sulfides or a decrease in the δ 34S value of aqueous sulfide due to oxidation of the ore fluid in the later stages of deposition. The latter hypothesis is favored because the lead isotopic compositions of the same vein minerals do not indicate an influx of sediment-derived lead and because of the appearance of barite in the final stages of several vein deposits. The majority of pyrite and galena analyses from vein and manto ores are compatible with precipitation from

  1. Double Layers: Potential Formation and Related Nonlinear Phenomena in Plasmas: Proceedings of the 5th Symposium

    Science.gov (United States)

    Iizuka, S.

    1998-02-01

    The Table of Contents for the book is as follows: * PREFACE * INTERNATIONAL SCIENTIFIC COMMITTEE * LOCAL ORGANIZING COMMITTEE AT TOHOKU UNIVERSITY * CHAPTER 1: DOUBLE LAYERS, SHEATHS, AND POTENTIAL STRUCTURES * 1.1 Double Layers * On Fluid Models of Stationary, Acoustic Double Layers (Invited) * Particle Simulation of Double Layer (Invited) * Space-Time Dependence of Non-Steady Double Layers * The Role of Low Energy Electrons for the Generation of Anode Double Layers in Glow Discharges * Arbitrary Amplitude Ion-Acoustic Double Layers in a Dusty Plasma * 1.2 Sheaths * Bounded Plasma Edge Physics as Observed from Simulations in 1D and 2D (Invited) * Control of RF Sheath Structure in RF Diode Discharge * Observation of Density Gradients with Fine Structures and Low Frequency Wave Excitation at the Plasma-Sheath Boundary * Double Sheath Associated with an Electron Emission to a Plasma Containing Negative Ions * Sheath Edge and Floating Potential for Multi-Species Plasmas Including Dust Particles * 1.3 Potential Structures and Oscillations * Potential Structure Formed at a Constriction of a DC He Positive Column and its Coupling with Ionization Wave * Potential Structure in a New RF Magnetron Device with a Hollow Electrode * Potential Disruption in a RF Afterglow Electronegative Plasma * Potential Oscillation in a Strongly Asymmetry RF Discharge Containing Negative Ions * Effects of External Potential Control on Coulomb Dust Behavior * Potential Structure of Carbon Arc Discharge for High-Yield Fullerenes Formation * Control of Axial and Radial Potential Profiles in Tandem Mirrors (Invited) * CHAPTER 2: FIELD-ALIGNED ELECTRIC FIELDS AND RELATED PARTICLE ACCELERATIONS * 2.1 Field-Aligned Potential Formation * Formation of Large Potential Difference in a Plasma Flow along Converging Magnetic Field Lines (Invited) * Presheath Formation in front of an Oblique End-Plate in a Magnetized Sheet Plasma * Plasma Potential Formation Due to ECRH in a Magnetic Well * Electrostatic

  2. The uranium ore deposits in Ciudad Rodrigo Phyllites. about the possibility of new deposits; Los yacimientos uraniferos en las pizarras paleozoicas de Ciudad Rodrigo. sobre la posible existencia de nuevas mineralizaciones

    Energy Technology Data Exchange (ETDEWEB)

    Mingarro Martin, E.; Marin Benavente, C.

    1969-07-01

    The main features of the genesis of uranium deposits of the Fe mine type, are discussed in this paper. Pitchblende ore is related with phyllites bearing organic material and with geomorphological level, fossilized by eocene sediments. As a result, new uranium ore deposits are possible under Ciudad Rodrigo tertiary basin, tertiary cover depth being little more than three hundred feet. (Author)

  3. PGE geochemistry and Re Os dating of massive sulfide ores from the Baimazhai Cu Ni deposit, Yunnan province, China

    Science.gov (United States)

    Sun, Xiaoming; Wang, Shengwei; Sun, Weidong; Shi, Guiyong; Sun, Yali; Xiong, Dexin; Qu, Wenjun; Du, Andao

    2008-09-01

    The Baimazhai deposit in Yunnan Province is one of the largest Cu-Ni sulfide deposits hosted in mafic-ultramafic intrusions in China. Concentrations of platinum-group elements (PGE) in massive sulfide ores and host rocks from Baimazhai were determined by using inductively coupled plasma mass spectrometry (ICP-MS) following nickel sulfide fire assay pre-concentration. The results show that the total PGE (ΣPGE) are quite low, decreasing gradually from central massive ores (78.2-556 ppb) to olivine pyroxenite (0.472-67.0 ppb), gabbro (0.847 ppb) and, websterite (0.76-0.809). The intruded lamprophyre dykes also show low ΣPGE (2.98-4.07 ppb). The ΣPGE exhibit obvious positive correlations with Au, Ni and Cu contents. Primitive mantle normalized PGE patterns of the massive Cu-Ni ores are of the Pt-Pd type with relatively steep and trough-like patterns, which are similar to those of the host rocks. In addition, the Pt/Pd and Cu/Pd ratios of the massive sulfide ores are similar to those of olivine pyroxenite, gabbro and websterite. These characteristics suggest that sulfides in the massive ores are of magmatic origin, co-genetic with their host rocks. The relatively high Pt/Pd ratios of the Baimazhai massive sulfide ores (averaging 0.83) and their host rocks imply that the Baimazhai sulfides formed in a single sulfide saturation event, but not through multiple sulfide injections. High Ir contents (0.77-5.52 ppb, averaging 2.35 ppb) and dramatically variable Pd/Ir ratios (4.76-296, averaging 138) of the massive sulfide ores suggest that the Baimazhai sulfide ores might have suffered significant late stage hydrothermal alteration. The Baimazhai massive sulfide ores yield a Re-Os isochron age of 259 ± 20 Ma (MSWD = 0.025), which is the same as the major eruption stage of the Emeishan large igneous province and the Baimazhai intrusion, further supporting their magmatic origin. The initial 187Os/ 188Os value of 0.456 ± 0.026 indicates that crustal contamination has played

  4. Analysis of the Ore-Controlling Structure of Ductile Shear Zone Type Gold Deposit in Southern Beishan Area, Gansu, Northwest China

    Institute of Scientific and Technical Information of China (English)

    Chen Bailin; Wu Ganguo; Ye Dejin; Liu Xiaochun; Shu Bin; Yang Nong

    2007-01-01

    The ductile shear zone-type gold deposit is a kind that both the ore-forming mechanism and ore-controlling factors are closely related to the ductile shear zone and its evolution. Ductile shear zone develops in Beishan area, Gansu of Northwest China, and develops especially well in the south belt.The controls of the ductile shear zone on gold deposits are as follows. (1) The regional distribution of gold deposits (and gold spots) is controlled by the ductile shear zone. (2) The ductile-brittle shear zone is formed in the evolution process of ductile shear zone and both are only ore-bearing structures and control the shape, attitude, scale, and distribution of mineralization zones and ore-bodies. (3) Compresso-shear ductile deformation results in that the main kind of gold mineralization is altered mylonite type and the main alteralization is metasomatic. (4) Ore-bearing fracture systems are mainly P-type ones, some D-type and R-type ones, but only individual R'-type and T-type ones. (5) Dynamic differentiation and dynamic metamorphic hydrothermal solution resulting from ductile deformation is one of the sources of ore-forming fluid of gold mineralization, and this is identical with that ore-forming materials are mainly from metamorphic rocks, and ore-forming fluid is mainly composed of metamorphic water, and with the fluid inclusion and geo-chemical characteristics of the deposit. (6) There is a negative correlation between the gold abundance and susceptibility anisotropy (P) of the altered mylonlte samples from the deposit, which shows that the gold mineralization is slightly later than the structural deformation. All above further expound the ore-forming model of the ductile shear zone type of gold deposits.

  5. [Spectral characteristics and implications of quartz from Heliao lead-zinc polymetallic ore district in the south of Qinzhou-Hangzhou joint belt].

    Science.gov (United States)

    Lü, Wen-Chao; Yang, Zhi-Jun; Zhou, Yong-Zhang; Li, Hong-Zhong; Zeng, Xiang-Qing; Chen, Qing; Liang, Jin; Zeng, Chang-Yu

    2013-05-01

    The XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rock and far away from ore body rock is pure, while the quartz in near ore body rock contains a small amount of impurities. But such small amounts of impurities did not cause apparent change in the quartz lattice parameters. From far away from ore body rock-->near ore body rock-->mineralized rock, the crystallinity and order degree of quartz are higher and higher. And the quartz in the mineralized rock has a trend to change into low symmetry quartz. It's a unique to mineralized rock that the quartz's absorption peak at 1 050 cm(-1) was split into two strongest ones. It can be used as the signs of whether exists mineralization. The cause for the quartz microstructure changes may be related to the activities of late mineralized hydrothermal fluids. Late hydrothermal influence was very weak to the quartz far away from ore body rock. And through the impact of the multi-stage hydrothermal effect, the quartz in mineralized rock may be purified by recrystallization and structural adjustment. However the quartz in near ore body rock didn't have enough hydrothermal influence, so it's not pure. Genealogy research technology is a useful technique for in-depth exploration of study area mineralization process and metallogenic regularity.

  6. Involvement of impaired desmosome-related proteins in hypertrophic scar intraepidermal blister formation.

    Science.gov (United States)

    Tan, Jianglin; He, Weifeng; Luo, Gaoxing; Wu, Jun

    2015-11-01

    Hypertrophic scar is one of the unique fibrotic diseases in human. Intraepidermal blister is a common clinical symptom following the hypertrophic scar formation. However, little is known about the reason of blister creation. In this study, we selected three patients with hypertrophic scar as manifested by raised, erythematous, pruritic, blister and thickened appearance undergoing scar resection. The first scar sample was 6 months after burn from the neck of a 3 years old male patient with 10 score by Vancouver Scar Scale (VSS). The second scar sample was 12 months after burn from the dorsal foot of a 16 years old female patient with 13 score by VSS. The third one was 9 months after burn from the elbow of a 34 years old male patients with 13 score by VSS. In order to understand the molecular mechanism of blister formation, we screened the different protein expression between hypertrophic scar and normal skin tissue by means of isobaric tags for relative and absolute quantitation (iTRAQ) labeling technology and high throughput 2D LC-MS/MS. There were 48 proteins found to be downregulated in hypertrophic scar. Among the downregulated ones, plakophilin1 (PKP1), plakophilin3 (PKP3) and desmoplakin (DSP) were the desmosome-related proteins which were validated by immunohistochemistry and western blotting assay. Transmission electron microscopy further showed the considerably reduced size and intensity of hemidesmosome and desmosome in hypertrophic scar tissue, compared to control normal skin. Our data indicted for the first time that downregulation of DSP, PKP1 and PKP3 in hypertrophic scar might be responsible for intraepidermal blister formation. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

  7. The radio continuum-star formation rate relation in WSRT sings galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Heesen, Volker; Brinks, Elias [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Leroy, Adam K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Heald, George [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Braun, Robert [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Bigiel, Frank [Institut für theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Beck, Rainer, E-mail: e.brinks@herts.ac.uk, E-mail: v.heesen@soton.ac.uk, E-mail: aleroy@nrao.edu, E-mail: heald@astron.nl, E-mail: Robert.Braun@csiro.au, E-mail: bigiel@uni-heidelberg.de, E-mail: rbeck@mpifr-bonn.mpg.de [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2014-05-01

    We present a study of the spatially resolved radio continuum-star formation rate (RC-SFR) relation using state-of-the-art star formation tracers in a sample of 17 THINGS galaxies. We use SFR surface density (Σ{sub SFR}) maps created by a linear combination of GALEX far-UV (FUV) and Spitzer 24 μm maps. We use RC maps at λλ22 and 18 cm from the WSRT SINGS survey and Hα emission maps to correct for thermal RC emission. We compare azimuthally averaged radial profiles of the RC and FUV/mid-IR (MIR) based Σ{sub SFR} maps and study pixel-by-pixel correlations at fixed linear scales of 1.2 and 0.7 kpc. The ratio of the integrated SFRs from the RC emission to that of the FUV/MIR-based SF tracers is R{sub int}=0.78±0.38, consistent with the relation by Condon. We find a tight correlation between the radial profiles of the radio and FUV/MIR-based Σ{sub SFR} for the entire extent of the disk. The ratio R of the azimuthally averaged radio to FUV/MIR-based Σ{sub SFR} agrees with the integrated ratio and has only quasi-random fluctuations with galactocentric radius that are relatively small (25%). Pixel-by-pixel plots show a tight correlation in log-log diagrams of radio to FUV/MIR-based Σ{sub SFR}, with a typical standard deviation of a factor of two. Averaged over our sample we find (Σ{sub SFR}){sub RC}∝(Σ{sub SFR}){sub hyb}{sup 0.63±0.25}, implying that data points with high Σ{sub SFR} are relatively radio dim, whereas the reverse is true for low Σ{sub SFR}. We interpret this as a result of spectral aging of cosmic-ray electrons (CREs), which are diffusing away from the star formation sites where they are injected into the interstellar medium. This is supported by our finding that the radio spectral index is a second parameter in pixel-by-pixel plots: those data points dominated by young CREs are relatively radio dim, while those dominated by old CREs are slightly more RC bright than what would be expected from a linear extrapolation. We studied the ratio R of

  8. Drosophila Hook-Related Protein (Girdin) Is Essential for Sensory Dendrite Formation.

    Science.gov (United States)

    Ha, Andrew; Polyanovsky, Andrey; Avidor-Reiss, Tomer

    2015-08-01

    The dendrite of the sensory neuron is surrounded by support cells and is composed of two specialized compartments: the inner segment and the sensory cilium. How the sensory dendrite is formed and maintained is not well understood. Hook-related proteins (HkRP) like Girdin, DAPLE, and Gipie are actin-binding proteins, implicated in actin organization and in cell motility. Here, we show that the Drosophila melanogaster single member of the Hook-related protein family, Girdin, is essential for sensory dendrite formation and function. Mutations in girdin were identified during a screen for fly mutants with no mechanosensory function. Physiological, morphological, and ultrastructural studies of girdin mutant flies indicate that the mechanosensory neurons innervating external sensory organs (bristles) initially form a ciliated dendrite that degenerates shortly after, followed by the clustering of their cell bodies. Importantly, we observed that Girdin is expressed transiently during dendrite morphogenesis in three previously unidentified actin-based structures surrounding the inner segment tip and the sensory cilium. These actin structures are largely missing in girdin mutant. Defects in cilia are observed in other sensory organs such as those mediating olfaction and taste, suggesting that Girdin has a general role in forming sensory dendrites in Drosophila. These suggest that Girdin functions temporarily within the sensory organ and that this function is essential for the formation of the sensory dendrites via actin structures.

  9. Microinjection of valproic acid into the ventrolateral orbital cortex enhances stress-related memory formation.

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    Full Text Available There is collecting evidence suggesting that the process of chromatin remodeling such as changes in histone acetylation contribute to the formation of stress-related memory. Recently, the ventrolateral orbital cortex (VLO, a major subdivision of orbitofrontal cortex (OFC, was shown to be involved in antidepressant-like actions through epigenetic mechanisms. Here, we further investigated the effects of the histone deacetylase inhibitor (HDACi valproic acid (VPA on stress-related memory formation and the underlying molecular mechanisms by using the traditional two-day forced swimming test (FST. The results showed that VPA significantly increased the immobility time on day 2 when infused into the VLO before the initial forced swim stress on day 1. The learned immobility response to the stress was associated with increased phosphorylation of extracellular signal-regulated kinase (ERK in VLO and hippocampus on the first day. The levels of phosphorylated ERK (phospho-ERK in VLO and hippocampus were significantly decreased when retested 24 h later. The pretreatment with intra-VLO VPA infusion further reduced the activation of ERK on day 2 and day 7 compared with the saline controls. Moreover, the VPA infusion pretreatment also induced a significantly decreased BDNF level in the VLO on day 2, whereas no change was detected in the hippocampus. These findings suggest that VPA enhance the memories of emotionally stressful events and the ERK activity is implicated in stimulating adaptive and mnemonic processes in case the event would recur.

  10. Teacher formation related to socio-scientific issues: complexity, contributions and limitations of an educational practice

    Directory of Open Access Journals (Sweden)

    Mariuce Campos de Moraes

    2015-12-01

    Full Text Available This reflection refers to teacher formation related to socio-scientific issues. Whereas such matters take into account the impact of scientific development in society, including ethical aspects and encompass dilemmas involving a wide range of prospects for its resolution, we propose analysis of the complexity that is inherent in their teaching. Thus, we aimed to analyze different spaces and teaching time that produce and are produced in close linkage between theory and practice, as well as their contributions and limitations. The study required a dynamic conversation system that led to the analysis indicators. The issue of sustainability was shown to be feasible for educational planning as cover technical and scientific knowledge, ethical, social and economic pressures. The collective production allowed understand arguments and reflective-creative processes. The lived relations in schools has accompanied and limited the ideas expressed on the socio-scientific issues. We understand that the simultaneity of research and reflection in the sociocultural context has strengthened teacher formation.

  11. The Radio Continuum-Star Formation Rate Relation in WSRT SINGS Galaxies

    CERN Document Server

    Heesen, Volker; Leroy, Adam K; Heald, George; Braun, Robert; Bigiel, Frank; Beck, Rainer

    2014-01-01

    We study the spatially resolved Radio Continuum-Star Formation Rate (RC-SFR) relation using state-of-the-art star-formation (SF) tracers in a sample of 17 THINGS galaxies. We use hybrid Sigma_SFR maps (GALEX FUV plus Spitzer 24 mu), RC maps at 22/18 cm from the WSRT SINGS survey, and H-alpha maps to correct for thermal RC emission. We compare azimuthally averaged radial profiles of the RC and FUV/MIR-based Sigma_SFR maps and study pixel-by-pixel correlations at fixed linear scales of 1.2 and 0.7 kpc. The ratio of the integrated SFRs from the RC emission to that of the FUV/MIR-based SF tracers is R_int = 0.78 +/- 0.38, consistent with Condon's relation. We find a tight correlation between the radial profiles of the radio and FUV/MIR-based Sigma_SFR for the entire extent of the disk. The ratio R of the azimuthally averaged radio to FUV/MIR-based Sigma_SFR agrees with the integrated ratio with only small quasi-random fluctuations as function of radius. Pixel-by-pixel plots show a tight correlation in log-log dia...

  12. Cohesive strength of iron ore granules

    Directory of Open Access Journals (Sweden)

    Contreras Rafael Jaimes

    2017-01-01

    Full Text Available We present an experimental and numerical investigation of the mechanical strength of crude iron ore (Hematite granules in which capillary bonds between primary particles are the source of internal cohesion. The strength is measured by subjecting the granules to vertical compression between two plates. We show that the behavior of the granules is ductile with a well-defined plastic threshold which increases with the amount of water. It is found that the compressive strength scales with capillary cohesion with a pre-factor that is nearly independent of size polydispersity for the investigated range of parameters but increases with friction coefficient between primary particles. This weak dependence may be attributed to the class of fine particles which, due to their large number, behaves as a cohesive matrix that controls the strength of the granule.

  13. Cohesive strength of iron ore granules

    Science.gov (United States)

    Contreras, Rafael Jaimes; Berger, Nicolas; Izard, Edouard; Douce, Jean-François; Koltsov, Alexey; Delenne, Jean-Yves; Azema, Emilien; Nezamabadi, Saeid; van Loo, Frédéric; Pellenq, Roland; Radjai, Farhang

    2017-06-01

    We present an experimental and numerical investigation of the mechanical strength of crude iron ore (Hematite) granules in which capillary bonds between primary particles are the source of internal cohesion. The strength is measured by subjecting the granules to vertical compression between two plates. We show that the behavior of the granules is ductile with a well-defined plastic threshold which increases with the amount of water. It is found that the compressive strength scales with capillary cohesion with a pre-factor that is nearly independent of size polydispersity for the investigated range of parameters but increases with friction coefficient between primary particles. This weak dependence may be attributed to the class of fine particles which, due to their large number, behaves as a cohesive matrix that controls the strength of the granule.

  14. Exact linear modeling using Ore algebras

    CERN Document Server

    Schindelar, Kristina; Zerz, Eva

    2010-01-01

    Linear exact modeling is a problem coming from system identification: Given a set of observed trajectories, the goal is find a model (usually, a system of partial differential and/or difference equations) that explains the data as precisely as possible. The case of operators with constant coefficients is well studied and known in the systems theoretic literature, whereas the operators with varying coefficients were addressed only recently. This question can be tackled either using Gr\\"obner bases for modules over Ore algebras or by following the ideas from differential algebra and computing in commutative rings. In this paper, we present algorithmic methods to compute "most powerful unfalsified models" (MPUM) and their counterparts with variable coefficients (VMPUM) for polynomial and polynomial-exponential signals. We also study the structural properties of the resulting models, discuss computer algebraic techniques behind algorithms and provide several examples.

  15. Improved polynomial remainder sequences for Ore polynomials.

    Science.gov (United States)

    Jaroschek, Maximilian

    2013-11-01

    Polynomial remainder sequences contain the intermediate results of the Euclidean algorithm when applied to (non-)commutative polynomials. The running time of the algorithm is dependent on the size of the coefficients of the remainders. Different ways have been studied to make these as small as possible. The subresultant sequence of two polynomials is a polynomial remainder sequence in which the size of the coefficients is optimal in the generic case, but when taking the input from applications, the coefficients are often larger than necessary. We generalize two improvements of the subresultant sequence to Ore polynomials and derive a new bound for the minimal coefficient size. Our approach also yields a new proof for the results in the commutative case, providing a new point of view on the origin of the extraneous factors of the coefficients.

  16. Super-Enrichment of Dispersed Elements and Associated Ore Deposits

    Institute of Scientific and Technical Information of China (English)

    高振敏; 姚林波

    2004-01-01

    Dispersed elements do not always occur as associated elements in the ore deposits of other elements. Instead, they can constitute independent ore deposits. The focus of this paper is placed on the mechanism of super-enrichment of the four dispersed elements TI, Ge, Se, and Te under favorable geological conditions, where their enrichment coefficients are so high that their abundances can reach n×103-n×104, sometimes even up to n×106 times (e. g. Te) those of the crust. As a result, they can form their independent ore deposits. Studies have shown that such independent ore deposits are mostly distributed in the southwestern part of China, most of which belong to low-temperature ore deposits, ranging in age from Yanshanian to Himalayan(Cretaceous to Cenozoic), with a significant time gap with the host strata. Moreover, this paper also deals with the existing forms (as independent minerals, occurring isomorphously and being adsorbed) of the dispersed elements in those independent ore deposits. The discovery of independent ore deposits of dispersed elements is a great breakthrough in the study of dispersed element metallogenesis.

  17. Leaching hydrodynamics of weathered elution-deposited rare earth ore

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Both porosity (φ) and permeability (k) of the weathered elution-deposited rare earth ores are basic hydrodynamic parameters for RE leaching. The relationship between k and φ of two typical rare earth ores of South China in the packed bed was investigated by measuring the flow (Q) under various leaching pressure difference (Δp). The experimental results show that the relationship between k and φ is unique, moreover the relationship between Q and Δp is in accord with the Darcy's law. The effects of the type of ores, the leaching reagents and its concentration, the granule ore size on the leaching permeability have also been investigated. It is demonstrated that kH (for heavy RE ore, kH=35.98 mm2)>kM-H (for middle-heavy RE ore,kM-H=28.50 mm2), whereas k(NH4NO3)>k(NH4Cl)>k[(NH4)2SO4], and the k value increases with increasing leaching reagents concentration and granule ore size(k0.60~0.75 mm=99.96 mm2,k0.125~0.60 mm=11.83 mm2, k0.074~0.125 mm=0.84 mm2).

  18. Direct Biohydrometallurgical Extraction of Iron from Ore

    Energy Technology Data Exchange (ETDEWEB)

    T.C. Eisele

    2005-10-01

    A completely novel approach to iron extraction was investigated, based on reductive leaching of iron by anaerobic bacteria. Microorganisms were collected from an anaerobic bog where natural seepage of dissolved iron was observed. This mixed culture was used to reduce insoluble iron in a magnetite ore to the soluble ferrous (Fe{sup +2}) state. While dissolution rates were slow, concentrations of dissolved iron as high as 3487 mg/l could be reached if sufficient time was allowed. A factorial study of the effects of trace nutrients and different forms of organic matter indicated that the best dissolution rates and highest dissolved iron concentrations were achieved using soluble carbohydrate (sucrose) as the bacterial food source, and that nutrients other than nitrogen, phosphorus, potassium, sodium, and acetate were not necessary. A key factor in reaching high levels of dissolved iron was maintaining a high level of carbon dioxide in solution, since the solubility of iron carbonates increases markedly as the quantity of dissolved carbon dioxide increases. Once the iron is dissolved, it has been demonstrated that the ferrous iron can then be electroplated from solution, provided that the concentration of iron is sufficiently high and the hydrogen ion concentration is sufficiently low. However, if the leaching solution is electrolyzed directly, organic matter precipitates at the cathode along with the metallic iron. To prevent this problem, the ferrous iron should be separated from the bulk solution in a more concentrated, purified form. One route to accomplishing this is to take advantage of the change in solubility of ferrous iron as a function of carbon dioxide concentration. By cycling the concentration of carbon dioxide in solution, it is possible to produce an iron-rich concentrate that should be suitable for electrolysis. This represents the first viable hydrometallurgical method for leaching iron directly from ore and producing metallic iron.

  19. THE NEOPROTEROZOIC ISLAND-ARC ASSOCIATION OF THE MUKODEK GOLD-ORE FIELD, NORTHERN BAIKAL AREA

    Directory of Open Access Journals (Sweden)

    V. A. Vanin

    2015-09-01

    Full Text Available Metamorphosed volcanic rocks of the Ushmukan suite were studied in the Mukodek gold-ore field located in the Baikal-Muya belt in the Northern Baikal area, Russia. The Ushmukan suite shows interleaving of ortoschists which compositions are widely variable. Basalt-andesite-dacite series of normal alkalinity are the substrate of the studied metavolcanic rocks. Based on the set of geochemical characteristics, it is concluded that the rocks were formed in suprasubduction geodynamic conditions corresponding to a mature island arc. The proximity of the geological locations and the similarity of the geochemical characteristics of the volcanic rocks of the Ushmukan suite and rocks of the Kelyan suite (Neoproterozoic, 823 Ma, which have similar compositions, give grounds to consider these two rock suites as age peers. Specific features of gold distribution through the Mukodek gold-ore field are analyzed. Industrial gold contents are recorded only in berezite-listvenite metasomatic rocks of the gold-quartz-sulfide formation which were formed on metavolcanic rocks of the Ushmukan suite. It is concluded that the volcanic rocks, which are specific of the island-arc setting, could be a source of gold for deposits in the Mukodek gold-ore field. 

  20. Iron ore industry emissions as a potential ecological risk factor for tropical coastal vegetation.

    Science.gov (United States)

    Kuki, Kacilda N; Oliva, Marco A; Pereira, Eduardo G

    2008-07-01

    In the coastal zone of the Espírito Santo state, Brazil, fragments of restinga, which form a natural ecosystem, share their space with an increasing number of iron ore industries. The iron ore dust and SO(2) originating from the industry processing activities can interfere with the vegetation of the adjacent ecosystems at various levels. This study was undertaken in order to evaluate the effects of industry emissions on representative members of the restinga flora, by measuring physiological and phenological parameters. Foliar samples of Ipomoea pes caprae, Canavalia rosea, Sophora tomentosa, and Schinus terebinthifolius were collected at three increasing distances from an ore industry (1.0, 5.0, and 15.0 km), and were assessed for their dust deposition, chlorophyll, and Fe content. Phenological monitoring was focused on the formation of shoots, flowers, and fruits and was also performed throughout the course of a year. The results showed that the edaphic characteristics and the mineral constitutions of the plants were affected by industry emissions. In addition, the chlorophyll content of the four species increased with proximity to the industry. Phenological data revealed that the reproductive effort, as measured by fruit production, was affected by emissions and S. tomentosa was the most affected species. The use of an integrative approach that combines biochemical and ecological data indicates that the restinga flora is under stress due to industry emissions, which on a long-term basis may put the ecosystem at risk.

  1. Effect of Tourmaline-Doped on the Far Infrared Emission of Iron Ore Tailings Ceramics.

    Science.gov (United States)

    Liu, Jie; Meng, Junping; Liang, Jinsheng; Zhang, Hongchen; Gu, Xiaoyang

    2016-04-01

    Iron ore tailings as secondary resources have been of great importance to many countries in the world. Their compositions are similar to that of infrared emission ceramics, but there are few reports about it. In addition, tourmaline has high infrared emission properties due to its unique structure. With the purpose of expanding functional utilization of iron ore tailings, as well as reducing the production cost of far infrared ceramics, a new kind of far infrared emission ceramics was prepared by using iron ore tailings, calcium carbonate, silica, and natural tourmaline. The ceramics powders were characterized by Fourier transform infrared spectroscope, X-ray diffraction and scanning electron microscopy, respectively. The results show that after being sintered at 1065 °C, the percentage of pseudobrookite and lattice strain of samples increased with increasing the elbaite content. Furthermore, the added tourmaline was conducive to the densification sintering of ceramics. The appearance of Li-O vibration at 734.73 cm-1, as well as the strengthened Fe-O vibration at 987.68 cm-1 were attributed to the formation of Li0.375Fe1.23Ti1.4O5 solid solution, which led the average far infrared emissivity of ceramics increase from 0.861 to 0.906 within 8-14 µm.

  2. Laser-induced breakdown spectroscopy measurements of uranium and thorium powders and uranium ore

    Energy Technology Data Exchange (ETDEWEB)

    Judge, Elizabeth J. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Barefield, James E., E-mail: jbarefield@lanl.gov [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Berg, John M. [Manufacturing Engineering and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Clegg, Samuel M.; Havrilla, George J.; Montoya, Velma M.; Le, Loan A.; Lopez, Leon N. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-05-01

    Laser-induced breakdown spectroscopy (LIBS) was used to analyze depleted uranium and thorium oxide powders and uranium ore as a potential rapid in situ analysis technique in nuclear production facilities, environmental sampling, and in-field forensic applications. Material such as pressed pellets and metals, has been extensively studied using LIBS due to the high density of the material and more stable laser-induced plasma formation. Powders, on the other hand, are difficult to analyze using LIBS since ejection and removal of the powder occur in the laser interaction region. The capability of analyzing powders is important in allowing for rapid analysis of suspicious materials, environmental samples, or trace contamination on surfaces since it most closely represents field samples (soil, small particles, debris etc.). The rapid, in situ analysis of samples, including nuclear materials, also reduces costs in sample collection, transportation, sample preparation, and analysis time. Here we demonstrate the detection of actinides in oxide powders and within a uranium ore sample as both pressed pellets and powders on carbon adhesive discs for spectral comparison. The acquired LIBS spectra for both forms of the samples differ in overall intensity but yield a similar distribution of atomic emission spectral lines. - Highlights: • LIBS analysis of mixed actinide samples: depleted uranium oxide and thorium oxide • LIBS analysis of actinide samples in powder form on carbon adhesive discs • Detection of uranium in a complex matrix (uranium ore) as a precursor to analyzing uranium in environmental samples.

  3. Mechanism of sodium chloride in promoting reduction of high-magnesium low-nickel oxide ore.

    Science.gov (United States)

    Zhou, Shiwei; Wei, Yonggang; Li, Bo; Wang, Hua; Ma, Baozhong; Wang, Chengyan

    2016-07-04

    Sodium chloride has been proved that it is an effective promoter for the reduction of high-magnesium, low-nickel oxide ore. The aim of current work is to clarify the promotion behavior of sodium chloride in the roasting reduction process. The influence of moisture on the reduction of ore in the presence of sodium chloride is studied to get clear comprehension of promotion process. In the presence of moisture, the HCl is produced by pyrohydrolysis of sodium chloride for chlorinating nickel and iron oxides, moreover, interactions between metallic oxides and sodium chloride are also a way for chlorination at high temperature (>802 °C); subsequently, the metal chloride would be reduced by reductant. In the absence of moisture, the magnetic separation results show that the recoveries of iron and nickel have a significant increase; moreover, olivine structure would be destroyed gradually with the increase of roasting temperature in the action of sodium chloride, and the sodium chloride existed in high-magnesium, low-nickel oxide ore could make the NiO isolate from NiO-bearing minerals. The NiO reacts with Fe2O3 at high temperature to form NiFe2O4, which is conductive to the formation of Ni-Fe alloy during the reduction process.

  4. Dielectric behaviour of MgFe2O4 prepared from chemically beneficiated iron ore rejects

    Indian Academy of Sciences (India)

    K S Rane; V M S Verenkar; P Y Sawant

    2001-06-01

    Chemically beneficiated high silica/alumina iron ore rejects (27–76% Fe2O3) were used to synthesize iron oxides of purity 96–98% with SiO2/Al2O3 ratio reduced to 0.03. The major impurities on chemical beneficiations were Al, Si, and Mn in the range 2–3%. A 99.73% purity Fe2O3 was also prepared by solvent extraction method using methyl isobutyl ketone (MIBK) from the acid extracts of the ore rejects. The magnesium ferrite, MgFe2O4, prepared from these synthetic iron oxides showed high resistivity of ∼ 108 ohm cm. All ferrites showed saturation magnetization, 4s, in the narrow range of 900–1200 Gauss and the Curie temperature, c, of all these fell within a small limit of 670 ± 30 K. All ferrites had low dielectric constants ('), 12–15, and low dielectric loss, tan , which decreased with the increase in frequency indicating a normal dielectric dispersion found in ferrites. The presence of insignificant amount of polarizable Fe2+ ions can be attributed to their high resistances and low dielectric constants. Impurities inherent in the samples had no marked influence on the electrical properties of the ferrites prepared from the iron ore rejects, suggesting the possibility of formation of ferrite of constant composition, MgFe2O4, of low magnetic and dielectric losses at lower temperatures of 1000°C by ceramic technique.

  5. Pelletisation Behavior of Fluxed Iron Ore Pellets of Varying Basicities Made with Waste Fines

    Directory of Open Access Journals (Sweden)

    Alok Sarkar

    2013-10-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE The present study deals with the utilization of fines generated from comminution process (crushing, grinding and screening of the Run of Mines into value added products i.e. fluxed iron ore pellets. The study comprises to understand the physical and mechanical behavior of five distinguished chemical compositions of green and dried iron ore pellets with respect to a typical Mini Blast furnace (MBF burden data and furnace operating parameter. The maximum basicity of pellets was calculated 2.37 to make slag neutral when blast furnace runs at 100% high ash coke (avg. ash content= 29%. The crushing strength and drop number of various green pellets were measured. Green Crushing Strength was decreased with increasing lime fines. The addition of lime fines as a burnt lime, which has acicular structure creates less plasticity and brittle like fracture occurred. Due to formation of hard CaCO3 layer on the surface, after increasing lime contain crushing strength was increased in the air and oven dry pellets with respect to acid pellet (0% lime fines addition. [How to cite this article: Sarkar, A., Mandal, A.K., and Sinha, O.P. (2013 Pelletisation Behavior of Fluxed Iron Ore Pellets of Varying Basicities Made with Waste Fines. International Journal of Science and Engineering, 5(2,9-14. Doi: 10.12777/ijse.5.2.9-14] 

  6. Kinetics and thermodynamics of the attack of a phosphate ore by acid solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Antar, K. [Faculty of Science of Tunis, Chemistry Department, Applied Thermodynamics Laboratory, 2092 Tunis El Manar (Tunisia); Jemal, M. [Faculty of Science of Tunis, Chemistry Department, Applied Thermodynamics Laboratory, 2092 Tunis El Manar (Tunisia)], E-mail: jemal@planet.tn

    2008-08-15

    A calorimetric study of the kinetics and thermodynamics of the attack of a phosphate ore from Gafsa region (Tunisia) by phosphoric acid and by a mixture of phosphoric acid and sulfuric acids is undertaken at different temperatures. Two samples of the same ore having different grain size have been used. At 25 deg. C, the dissolution enthalpy in phosphoric acid solution equals -233.6 {+-} 2.2 J/g for both of the samples. Attack by the mixture of acids is strongly dependent on the solid granulometry. Interpretation of the calorimetric results by Avrami model shows the existence of three domains attributed to phosphate ore dissolution/H{sub 2}PO{sub 4}{sup -} neutralisation, hemihydrate (HH) precipitation and hemihydrate/dihydrate (DH) transformation. The attack by the acid mixture was performed at higher temperatures and showed in addition the transitional formation of the anhydrous sulfate (AH) at T {>=} 55 deg. C, which transforms into dihydrate after the HH/DH transformation.

  7. Iron Ore Industry Emissions as a Potential Ecological Risk Factor for Tropical Coastal Vegetation

    Science.gov (United States)

    Kuki, Kacilda N.; Oliva, Marco A.; Pereira, Eduardo G.

    2008-07-01

    In the coastal zone of the Espírito Santo state, Brazil, fragments of restinga, which form a natural ecosystem, share their space with an increasing number of iron ore industries. The iron ore dust and SO2 originating from the industry processing activities can interfere with the vegetation of the adjacent ecosystems at various levels. This study was undertaken in order to evaluate the effects of industry emissions on representative members of the restinga flora, by measuring physiological and phenological parameters. Foliar samples of Ipomoea pes caprae, Canavalia rosea, Sophora tomentosa, and Schinus terebinthifolius were collected at three increasing distances from an ore industry (1.0, 5.0, and 15.0 km), and were assessed for their dust deposition, chlorophyll, and Fe content. Phenological monitoring was focused on the formation of shoots, flowers, and fruits and was also performed throughout the course of a year. The results showed that the edaphic characteristics and the mineral constitutions of the plants were affected by industry emissions. In addition, the chlorophyll content of the four species increased with proximity to the industry. Phenological data revealed that the reproductive effort, as measured by fruit production, was affected by emissions and S. tomentosa was the most affected species. The use of an integrative approach that combines biochemical and ecological data indicates that the restinga flora is under stress due to industry emissions, which on a long-term basis may put the ecosystem at risk.

  8. Realization of educational discipline «Physical culture» in formation of positive relations of children

    Directory of Open Access Journals (Sweden)

    Olhova-Marchuk N.V.

    2011-05-01

    Full Text Available Educational potential of contents of the subject «Physical culture» and its extramural kinds in formation of inter-personalities relations of younger schoolchildren is revealed. The pupils of 1-4 class took part in the experiment. It is exposed that the problem of culture formation of inter-personalities relations needs looking for new methods of its solution. It is proved that formation of inter-personalities relations of younger children is actively realized in the process of physical education.

  9. The relation between star formation rate and stellar mass of galaxies at z $\\sim$ 1-4

    CERN Document Server

    Katsianis, A; Wyithe, J S B

    2015-01-01

    The relation between the Star Formation Rate (SFR) and stellar mass (${\\rm M}_{\\star}$) of galaxies represents a fundamental constraint on galaxy formation. However, the observed amplitude of the star formation rate - stellar mass relation has not been successfully reproduced in simulations, indicating either that the halo accretion history and baryonic physics are poorly understood or that observations contain biases. In this paper, we examine the evolution of the SFR$-{\\rm M}_{\\star}$ relation of $z\\sim 1-4 $ galaxies and display the inconsistency between observed relations that are obtained using different techniques. We employ cosmological hydrodynamic simulations from various groups and compare these with a range of observations. The comparison suggests that using Spectral Energy Distributions (SEDs) to estimate star formation rates, dust corrections and stellar masses produces the most reliable SFR$-{\\rm M}_{\\star}$ relations. On the contrary, the combination of IR and UV luminosities (UV+IR) overpredic...

  10. Water leaching of titanium from ore flotation residue.

    Science.gov (United States)

    Jaworska, Malgorzata M; Guibal, Eric

    2003-01-01

    Copper ore tailings were tested for the stability of titanium submitted to water leaching in three different reactor systems (agitated vessel, bioreactor and percolated fixed-bed column). For each of these systems, titanium extraction did not exceed 1% of the available metal. Biomass removed from ore residue adsorbed a small part of the titanium with sorption capacities below 20-30 mg g(-1), but most of this biomass was sequestered in the ore residue. Oxygen and carbon dioxide concentrations were monitored and changes in concentration correlated with bacteria development at the initial stage of the process and to fungal development in the latter stages.

  11. Microstructure of Bentonite in Iron Ore Green Pellets

    OpenAIRE

    Bhuiyan, Iftekhar U.; Mouzon, Johanne; Schröppel, Birgit; Kaech, Andres; Dobryden, Illia; Forsmo, Seija P.E.; Hedlund, Jonas

    2017-01-01

    Sodium-activated calcium bentonite is used as a binder in iron ore pellets and is known to increase strength of both wet and dry iron ore green pellets. In this article, the microstructure of bentonite in magnetite pellets is revealed for the first time using scanning electron microscopy. The microstructure of bentonite in wet and dry iron ore pellets, as well as in distilled water, was imaged by various imaging techniques (e.g., imaging at low voltage with monochromatic and decelerated beam ...

  12. Biological-Chemical Oxidation of Ore Minerals at Pezinok Deposit

    Directory of Open Access Journals (Sweden)

    Martin Chovan

    2004-12-01

    Full Text Available The article presents results of leaching experiments of the comparison between chemical and biological-chemical leaching, at the same conditions in solution, of ores from the Sb-(Au- base metal deposit Pezinok (Malé Karpaty Mts., Western Carpathians, Slovakia. The research study shows the oxidation order and the progression of present ore minerals (löllingite, arsenopyrite, stibnite, native Sb, gudmundite, berthierite, pyrite, sphalerite and chalcopyrite. There are discussed differences between chemical and biological-chemical leaching activity of various ore minerals at the surface of polished sections. The extent of the leaching of sulphide minerals is significantly higher than that without bacteria.

  13. Start of exploration and mining of uranium ores in Hungary

    Energy Technology Data Exchange (ETDEWEB)

    Mikolay, I.; Szomolanyi, G. (Mecseki Ercbanyaszati Vallalat, Pecs II (Hungary))

    1983-09-01

    The mining of uranium ores is the youngest branch in the history of the Hungarian ore mining. The exploration for uranium ores started in Hungary in the decade from 1947, using simple methods at the beginning to apply more developed technologies later on. From the year 1952 Soviet geologists and geophysicists joined the explorations using the most advanced instruments, in co-operation with the Hungarian experts. From 1953 explorations and developments have been concentrated on the SW area of Mountain Mecsek so that by 1957 the preliminary conditions of a successful Hungarian uranium mining were established.

  14. 40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The provisions of...

  15. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The provisions of...

  16. 40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The provisions of...

  17. 40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... nickel ore subcategory. 440.70 Section 440.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The provisions of this...

  18. 40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... mercury ore subcategory. 440.40 Section 440.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The provisions of subpart...

  19. 40 CFR 440.110 - Applicability; description of the platinum ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of...

  20. 40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The provisions of...

  1. Formation of Si-Al-Mg-Ca-rich zoned magnetite in an end-Permian phreatomagmatic pipe in the Tunguska Basin, East Siberia

    Science.gov (United States)

    Neumann, Else-Ragnhild; Svensen, Henrik H.; Polozov, Alexander G.; Hammer, Øyvind

    2017-03-01

    Magma-sediment interactions in the evaporite-rich Tunguska Basin resulted in the formation of numerous phreatomagmatic pipes during emplacement of the Siberian Traps. The pipes contain magnetite-apatite deposits with copper and celestine mineralization. We have performed a detailed petrographic and geochemical study of magnetite from long cores drilled through three pipe breccia structures near Bratsk, East Siberia. The magnetite samples are zoned and rich in Si (≤5.3 wt% SiO2), Ca, Al, and Mg. They exhibit four textural types: (1) massive ore in veins, (2) coating on breccia clasts, (3) replacement ore, and (4) reworked ore at the crater base. The textural types have different chemical characteristics. "Breccia coating" magnetite has relatively low Mg content relative to Si, as compared to the other groups, and appears to have formed at lower oxygen fugacity. Time series analyses of MgO variations in microprobe transects across Si-bearing magnetite in massive ore indicate that oscillatory zoning in the massive ore was controlled by an internal self-organized process. We suggest that hydrothermal Fe-rich brines were supplied from basalt-sediment interaction zones in the evaporite-rich sedimentary basin, leading to magnetite ore deposition in the pipes. Hydrothermal fluid composition appears to be controlled by proximity to dolerite fragments, temperature, and oxygen fugacity. Magnetite from the pipes has attributes of iron oxide-apatite deposits (e.g., textures, oscillatory zoning, association with apatite, and high Si content) but has higher Mg and Ca content and different mineral assemblages. These features are similar to magnetite found in skarn deposits. We conclude that the Siberian Traps-related pipe magnetite deposit gives insight into the metamorphic and hydrothermal effects following magma emplacement in a sedimentary basin.

  2. Runaway Growth of Mars and Implications for Core Formation Relative to Earth

    Science.gov (United States)

    Halliday, A. N.; Wood, B. J.; Kleine, T.

    2005-12-01

    Martian meteorites are relatively young objects widely considered to reflect melting of the mantle of Mars over the past 1.4 Gyr. As such, their trace element compositions partly reflect the complex history of melting in the martian mantle. Hafnium (Hf) and tungsten (W) having different bulk distribution coefficients during mantle melting and thus may be fractionated by such processes. This explains why Hf/W, as measured in martian meteorites, is decoupled from W isotopic compositions, which would have been produced by 182Hf decay during the first 50 Myrs of the solar system. In contrast, little fractionation is expected among Ba, Th, and W, all of which have a similar incompatibility during melting in Earth's mantle. Assuming this is also true for the martian mantle, Ba/W and Th/W may be used as a proxy for the degree of metal segregation. The W isotopic compositions indeed show some relationship with the degree of mantle W depletion predicted to have been caused by core formation, as deduced from measured Ba/W or Th/W. These indices, as well as the W isotopic variations themselves, provide evidence of heterogeneity probably caused by early core formation, which can be compared with the effects generated by early partial melting as recorded by the 146Sm-142Nd system. Shergottites such as Zagami with no Nd isotopic effect and hence no indication of Hf/W fractionation from partial melting appear to define rapid timescales for accretion and core formation of about one million years, implying a runaway growth mechanism of accretion for Mars. This is consistent with certain dynamical models and argues against early migration of Jupiter-sized objects through the inner solar system. Melting and core formation on Mars appears to have continued for at least 10 Myrs as recorded in the W and Nd isotopic compositions of some other martian meteorites. This accretion and core formation history is strikingly different from that of the Earth. The last major stage of Earth

  3. Igneous Hydrothermal Alteration and Ore-Forming Processes in the Land's End Granite, Nanjizal

    OpenAIRE

    Eik, Marte

    2015-01-01

    This study addresses the hydrothermal alteration and mineralization related to a system of tourmaline-quartz veins intersecting biotite-granite in Nanjizal, in the Land s End granites of the cornubian batholith. Nanjizal is an important site as it is one of the few locations in the southern segment of the Land s End Granite where magmatic-hydrothermal tin mineralizations have been mined. The aim is to identify the alteration-patterns and their correlation with hydrothermal ore-forming events ...

  4. Ore-fluid evolution at the Sasa Pb-Zn skarn deposit, Republic of Macedonia

    OpenAIRE

    Strmić Palinkas, Sabina; Tasev, Goran; Serafimovski, Todor; Palinkas, Ladislav; Šmajgl, Daniela; Peltekovski, Zlatko

    2013-01-01

    The Sasa Pb-Zn skarn deposit is located in the Serbo-Macedonian massif approximately 100 km east from Skopje, Republic of Macedonia. Ore reserves are estimated at 10 million metric tons with 7.5% lead and zinc. The deposit is hosted by the Lower Palaeozoic metamorphic complex composed of gneisses, marbles and quartz-graphite schists. The mineralisation is spatially and temporary related to Tertiary calc-alkaline magmatism. The volcanic rocks in the area are mostly quartz latite an...

  5. Direct iron ore reduction by methane in a fluidized bed. Final report, November 1989-December 1992

    Energy Technology Data Exchange (ETDEWEB)

    van der Vaart, D.R.; Conger, W.L.

    1993-08-01

    Novel process chemistry of methane in a fluidized bed was investigated to identify a more direct route to producing the reducing gas needed in the Direct Reduction of iron ore. A rather surprising result, however, of the study was the discovery of an inexpensive and attrition-resistant catalytic material for methane oxidative coupling. The iron oxide impregnated, non-porous silica oxide was found to be relatively active, and quite selective when steam was added to the methane/air feed.

  6. Overexpression of stress-related genes enhances cell viability and velum formation in Sherry wine yeasts.

    Science.gov (United States)

    Fierro-Risco, Jesús; Rincón, Ana María; Benítez, Tahía; Codón, Antonio C

    2013-08-01

    Flor formation and flor endurance have been related to ability by Saccharomyces cerevisiae flor yeasts to resist hostile conditions such as oxidative stress and the presence of acetaldehyde and ethanol. Ethanol and acetaldehyde toxicity give rise to formation of reactive oxygen species (ROS) and loss of cell viability. Superoxide dismutases Sod1p and Sod2p and other proteins such as Hsp12p are involved in oxidative stress tolerance. In this study, genes SOD1, SOD2, and HSP12 were overexpressed in flor yeast strains FJF206, FJF414 and B16. In the SOD1 and SOD2 transformant strains superoxide dismutases encoded by genes SOD1 and SOD2 increased their specific activity considerably as a direct result of overexpression of genes SOD1 and SOD2, indirectly, catalase, glutathione reductase, and glutathione peroxidase activities increased too. The HSP12 transformant strains showed higher levels of glutathione peroxidase and reductase activities. These transformant strains showed an increase in intracellular glutathione content, a reduction in peroxidized lipid concentration, and higher resistance to oxidative stress conditions. As a result, flor formation by these strains took place more rapidly than by their parental strains, velum being thicker and with higher percentages of viable cells. In addition, a slight decrease in ethanol and glycerol concentrations, and an increase in acetaldehyde were detected in wines matured under velum formed by transformant strains, as compared to their parental strains. In the industry, velum formed by transformant strains with increased viability may result in acceleration of both metabolism and wine aging, thus reducing time needed for wine maturation.

  7. The composition of fluid inclusions in ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type Zn-Pb deposits Poland: Genetic and environmental implications

    Science.gov (United States)

    Viets, J.G.; Hofstra, A.H.; Emsbo, P.; Kozlowski, A.

    1996-01-01

    The composition of fluids extracted from ore and gangue sulfide minerals that span most of the paragenesis of the Silesian-Cracow district was determined using a newly developed ion chromatographic (IC) technique. Ionic species determined were Na+, NH+4, Ca2+, Mg2+, K+, Rb+, Sr2+, Ba2+, Cl-, Br-, F-, I-, PO3-4, CO2-3, HS-, S2O2-3, SO2-4, NO-3, and acetate. Mineral samples included six from the Pomorzany mine and one from the Trzebionka mine which are hosted in the Triassic Muschelkalk Formation, and two samples of drill core from mineralized Upper Devonian strata. Nine paragenetically identifiable sulfide minerals occur throughout the Silesian-Cracow district. These include from earliest to latest: early iron sulfides, granular sphalerite, early galena, light-banded sphalerite, galena, dark-banded sphalerite, iron sulfides, late dark-banded sphalerite with late galena, and late iron sulfides. Seven of the minerals were sampled for fluid inclusion analysis in this study. Only the early iron sulfides and the last galena stage were not sampled. Although the number of analyses are limited to nine samples and two replicates and there is uncertainty about the characteristics of the fluid inclusions analyzed, the data show clear temporal trends in the composition of the fluids that deposited these minerals. Fluid inclusions in minerals deposited later in the paragenesis have significantly more K+, Br-, NH+4, and acetate but less Sr2+ than those deposited earlier in the paragenesis. The later minerals are also characterized by isotopically lighter sulfur and significantly more Tl and As in the solid minerals. The change in ore-fluid chemistry is interpreted to reflect a major change in the hydrologic regime of the district. Apparently, the migrational paths of ore fluids from the Upper Silesian basin changed during ore deposition and the fluids which deposited early minerals reacted with aquifers with very different geochemical characteristics than those that deposited

  8. Studies on Sulfating Roasting Process for Mianning Bastnasite and Baotou Mixed RE Concentrate Ore

    Institute of Scientific and Technical Information of China (English)

    Miao Guangli

    2004-01-01

    Some processes of sulfating roasting and water leaching of crude Mianning RE concentrate ore, of fine Mianning RE concentrate ore, of Baotou RE concentrate ore and of their mixture were investigated.The result shows that the mixture of Mianning and Baotou RE concentrate ore has the optimum leaching rate and rate of recovery when the mixture ratio is 1:4.The recovery rate of the mixture is higher by 14.76% than that of crude Mianning RE concentrate ore, by 5.0 % than that of Mianning fine RE concentrate ore and by 2.4 % than that of Baotou RE concentrate ore.

  9. The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

    Science.gov (United States)

    Deditius, Artur P.; Reich, Martin; Kesler, Stephen E.; Utsunomiya, Satoshi; Chryssoulis, Stephen L.; Walshe, John; Ewing, Rodney C.

    2014-09-01

    The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ∼30 to ∼600 °C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ∼200 to ∼500 °C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and

  10. Age-related characteristics of risky decision-making and progressive expectation formation.

    Science.gov (United States)

    Kardos, Zsófia; Kóbor, Andrea; Takács, Ádám; Tóth, Brigitta; Boha, Roland; File, Bálint; Molnár, Márk

    2016-10-01

    During daily encounters, it is inevitable that people take risks. Investigating the sequential processing of risk hazards involve expectation formation about outcome contingencies. The present study aimed to explore risk behavior and its neural correlates in sequences of decision making, particularly in old age, which represents a critical period regarding risk-taking propensity. The Balloon Analogue Risk Task was used in an electrophysiological setting with young and elderly age groups. During the task each additional pump on a virtual balloon increased the likelihood of a balloon burst but also increased the chance to collect more reward. Event-related potentials associated with rewarding feedback were analyzed based on the forthcoming decisions (whether to continue or to stop) in order to differentiate between states of expectation towards gain or loss. In the young, the reward positivity ERP component increased as a function of reward contingencies with the largest amplitude for rewarding feedback followed by the decision to stop. In the elderly, however, reward positivity did not reflect the effect of reward structure. Behavioral indices of risk-taking propensity suggest that the performance of the young and the elderly were dissociable only with respect to response times: The elderly was characterized by hesitation and more deliberative decision making throughout the experiment. These findings signify that sequential tracking of outcome contingencies has a key role in cost-efficient action planning and progressive expectation formation.

  11. Low-metallicity star formation: relative impact of metals and magnetic fields

    Science.gov (United States)

    Peters, Thomas; Schleicher, Dominik R. G.; Smith, Rowan J.; Schmidt, Wolfram; Klessen, Ralf S.

    2014-08-01

    Low-metallicity star formation poses a central problem of cosmology, as it determines the characteristic mass scale and distribution for the first and second generations of stars forming in our Universe. Here, we present a comprehensive investigation assessing the relative impact of metals and magnetic fields, which may both be present during low-metallicity star formation. We show that the presence of magnetic fields generated via the small-scale dynamo stabilizes the protostellar disc and provides some degree of support against fragmentation. In the absence of magnetic fields, the fragmentation time-scale in our model decreases by a factor of ˜10 at the transition from Z = 0 to Z > 0, with subsequently only a weak dependence on metallicity. Similarly, the accretion time-scale of the cluster is set by the large-scale dynamics rather than the local thermodynamics. In the presence of magnetic fields, the primordial disc can become completely stable, therefore forming only one central fragment. At Z > 0, the number of fragments is somewhat reduced in the presence of magnetic fields, though the shape of the mass spectrum is not strongly affected in the limits of the statistical uncertainties. The fragmentation time-scale, however, increases by roughly a factor of 3 in the presence of magnetic fields. Indeed, our results indicate comparable fragmentation time-scales in primordial runs without magnetic fields and Z > 0 runs with magnetic fields.

  12. Chunk formation in immediate memory and how it relates to data compression.

    Science.gov (United States)

    Chekaf, Mustapha; Cowan, Nelson; Mathy, Fabien

    2016-10-01

    This paper attempts to evaluate the capacity of immediate memory to cope with new situations in relation to the compressibility of information likely to allow the formation of chunks. We constructed a task in which untrained participants had to immediately recall sequences of stimuli with possible associations between them. Compressibility of information was used to measure the chunkability of each sequence on a single trial. Compressibility refers to the recoding of information in a more compact representation. Although compressibility has almost exclusively been used to study long-term memory, our theory suggests that a compression process relying on redundancies within the structure of the list materials can occur very rapidly in immediate memory. The results indicated a span of about three items when the list had no structure, but increased linearly as structure was added. The amount of information retained in immediate memory was maximal for the most compressible sequences, particularly when information was ordered in a way that facilitated the compression process. We discuss the role of immediate memory in the rapid formation of chunks made up of new associations that did not already exist in long-term memory, and we conclude that immediate memory is the starting place for the reorganization of information. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Low-metallicity star formation: Relative impact of metals and magnetic fields

    CERN Document Server

    Peters, Thomas; Smith, Rowan J; Schmidt, Wolfram; Klessen, Ralf S

    2014-01-01

    Low-metallicity star formation poses a central problem of cosmology, as it determines the characteristic mass scale and distribution for the first and second generations of stars forming in our Universe. Here, we present a comprehensive investigation assessing the relative impact of metals and magnetic fields, which may both be present during low-metallicity star formation. We show that the presence of magnetic fields generated via the small-scale dynamo stabilises the protostellar disc and provides some degree of support against fragmentation. In the absence of magnetic fields, the fragmentation timescale in our model decreases by a factor of ~10 at the transition from Z=0 to Z>0, with subsequently only a weak dependence on metallicity. Similarly, the accretion timescale of the cluster is set by the large-scale dynamics rather than the local thermodynamics. In the presence of magnetic fields, the primordial disc can become completely stable, therefore forming only one central fragment. At Z>0, the number of ...

  14. MAPPING CHILDREN’S POLITICS: SPATIAL STORIES, DIALOGIC RELATIONS AND POLITICAL FORMATION

    Science.gov (United States)

    Elwood, Sarah; Mitchell, Katharyne

    2015-01-01

    This article confronts a persistent challenge in research on children’s geographies and politics: the difficulty of recognizing forms of political agency and practice that by definition fall outside of existing political theory. Children are effectively “always already” positioned outside most of the structures and ideals of modernist democratic theory, such as the public sphere and abstracted notions of communicative action or “rational” speech. Recent emphases on embodied tactics of everyday life have offered important ways to recognize children’s political agency and practice. However, we argue here that a focus on spatial practices and critical knowledge alone cannot capture the full range of children’s politics, and show how representational and dialogic practices remain a critical element of their politics in everyday life. Drawing on de Certeau’s notion of spatial stories, and Bakhtin’s concept of dialogic relations, we argue that children’s representations and dialogues comprise a significant space of their political agency and formation, in which they can make and negotiate social meanings, subjectivities, and relationships. We develop these arguments with evidence from an after-school activity programme we conducted with 10–13 year olds in Seattle, Washington, in which participants explored, mapped, wrote and spoke about the spaces and experiences of their everyday lives. Within these practices, children negotiate autonomy and self-determination, and forward ideas, representations, and expressions of agreement or disagreement that are critical to their formation as political actors. PMID:25642017

  15. The relation between star formation, morphology and local density in high redshift clusters and groups

    CERN Document Server

    Poggianti, Bianca M; Finn, Rose; Bamford, Steven; De Lucia, Gabriella; Varela, Jesus; Aragon-Salamanca, Alfonso; Halliday, Claire; Noll, Stefan; Saglia, Roberto; Zaritsky, Dennis; Best, Philip; Clowe, Douglas; Milvang-Jensen, Bo; Jablonka, Pascale; Pello, Roser; Rudnick, Gregory; Simard, Luc; von der Linden, Anja; White, Simon

    2008-01-01

    We investigate how the [OII] properties and the morphologies of galaxies in clusters and groups at z=0.4-0.8 depend on projected local galaxy density, and compare with the field at similar redshifts and clusters at low-z. In both nearby and distant clusters, higher-density regions contain proportionally fewer star-forming galaxies, and the average [OII] equivalent width of star-forming galaxies is independent of local density. However, in distant clusters the average current star formation rate (SFR) in star-forming galaxies seems to peak at densities ~15-40 galaxies Mpc^{-2}. At odds with low-z results, at high-z the relation between star-forming fraction and local density varies from high- to low-mass clusters. Overall, our results suggest that at high-z the current star formation (SF) activity in star-forming galaxies does not depend strongly on global or local environment, though the possible SFR peak seems at odds with this conclusion. We find that the cluster SFR normalized by cluster mass anticorrelate...

  16. Ore-forming model for Cu-Au-Fe ore deposits associated with granites in the Truongson ore-forming belt of Laos.%老挝长山成矿带与花岗岩有关的铜金铁矿床的成矿模式

    Institute of Scientific and Technical Information of China (English)

    赵红娟; 陈永清; 卢映祥

    2011-01-01

    As an important part of the Tethyan metallogenic domain, Laos contains abundant mineral resources, especially rich Cu, Au, Fe, Al, and potash salt. Laos could exchange mineral advantages for economic advantages with China. The authors studied in detail the ore-forming geological background of the Truongson ore-forming belt in Laos, mineralization features and ore minerals of newly discovered porphyry Cu-Au deposits and skarn Fe ore deposits as well as their spatial relationships to the granite intrusions. On such a basis, an ore-forming model was tentatively established for the porphyry Cu-Au deposits, thus laying a foundation for building their ore-finding patterns and searching for the same ore deposits in this ore-forming belt. Based on both zircon U-Pb dating and the discrimination diagrams of Hf-Rb-Ta trace elements, it is inferred that these granites and related ore deposits might have been formed in an island arc setting developed by the subduction of the South China block beneath the Indochina block during Late Carboniferous.%老挝作为“特提斯成矿域”的重要组成部分,具有丰富的矿产资源,尤其是铜、金、铁、铝、钾盐等优势矿产与中国具有很强的互补性.初步论述了老挝的成矿地质背景和近年来发现的与花岗岩类有关的斑岩型铜-金矿床、矽卡岩型铁矿床的矿化地质特征、矿石矿物特征、矿化与岩体的空间关系,在此基础上初步建立了其成矿模式.基于同位素定年数据和Hf-Rb-Ta元素判别图,推测这些花岗岩及与其相关的矿床形成于晚石炭世华南地块向印支地块俯冲产生的火山岛弧环境.

  17. Relation between Silver Nanoparticle Formation Rate and Antioxidant Capacity of Aqueous Plant Leaf Extracts

    Directory of Open Access Journals (Sweden)

    Azat Akbal

    2016-01-01

    Full Text Available Correlation between the antioxidant capacity and silver nanoparticle formation rates of pomegranate (Punica granatum, quince (Cydonia oblonga, chestnut (Castanea sativa, fig (Ficus carica, walnut (Juglans cinerea, black mulberry (Morus nigra, and white mulberry (Morus alba leaf extracts is investigated at a fixed illumination. Silver nanoparticles formed in all plant leaf extracts possess round shapes with average particle size of 15 to 25 nm, whereas corresponding surface plasmon resonance peak wavelengths vary between 422 nm and 451 nm. Cupric reducing antioxidant capacity technique is used as a reference method to determine total antioxidant capacity of the plant leaf extracts. Integrated absorbance over the plasmon resonance peaks exhibits better linear relation with antioxidant capacities of various plant leaf extracts compared to peak absorbance values, with correlation coefficient values of 0.9333 and 0.7221, respectively.

  18. A model of relative translation and rotation in leader-follower spacecraft formations

    Directory of Open Access Journals (Sweden)

    Raymond Kristiansen

    2007-01-01

    Full Text Available In this paper, a model of a leader-follower spacecraft formation in six degrees of freedom is derived and presented. The nonlinear model describes the relative translational and rotationalmotion of the spacecraft, and extends previous work by providing a more complete factorization, together with detailed information about the matrices in the model. The resulting model shows many similarities with models for systems such as robot manipulators and marine vehicles. In addition, mathematical models of orbital perturbations due to gravitational variations, atmospheric drag, solar radiation and third-body effects are presented for completeness. Results from simulations are presented to visualize the properties of the model and to show the impact of the different orbital perturbations on the flight path.

  19. Application of Analytic Solution in Relative Motion to Spacecraft Formation Flying in Elliptic Orbit

    Science.gov (United States)

    Cho, Hancheol; Park, Sang-Young; Choi, Kyu-Hong

    2008-09-01

    The current paper presents application of a new analytic solution in general relative motion to spacecraft formation flying in an elliptic orbit. The calculus of variations is used to analytically find optimal trajectories and controls for the given problem. The inverse of the fundamental matrix associated with the dynamic equations is not required for the solution in the current study. It is verified that the optimal thrust vector is a function of the fundamental matrix of the given state equations. The cost function and the state vector during the reconfiguration can be analytically obtained as well. The results predict the form of optimal solutions in advance without having to solve the problem. Numerical simulation shows the brevity and the accuracy of the general analytic solutions developed in the current paper.

  20. International Thought of Tomonaga Sanjyuro: The Formation of "Self-State-International Relations" Paradigm in Modern Japan

    National Research Council Canada - National Science Library

    芝崎, 厚士

    2009-01-01

    This paper explores the life and thought of Tomonaga Sanjyuro (1871-1951) from historical and theoretical perspective, in order to find out formation of the epistemological base of understanding modern international relations in Japan...

  1. On the role of buoyancy force in the ore genesis of SEDEX deposits: Example from Northern Australia

    Institute of Scientific and Technical Information of China (English)

    YANG JianWen; FENG ZuoHai; LUO XianRong; CHEN YuanRong

    2009-01-01

    Finite element modeling on a highly conceptualized 2-D model of fluid flow and heat transport is un-dertaken to simulate the paleo-hydrological system as if the Mount Ise deposits were being formed in the Mount Isa basin, Northern Australia, and to evaluate the potential of buoyancy force in driving ba-sin-scale fluid flow for the formation of sedimentary-exhalative (SEDEX) deposits. Our numerical case studies indicate that buoyancy-driven fluid flow is controlled mainly by the fault penetration depth and its spatial relation with the aquifer. Marine water recharges the basin via one fault and flows through the aquifer where it is heated from below. The heated metalliferous fluid discharges to the basin floor via the other fault. The venting fluid temperatures are computed to be in the range of 115 to 160℃, with fluid velocities of 2.6 to 4.1 m/year over a period of 1 Ma. These conditions are suitable for the formation of a Mount Isa-sized zinc deposit, provided a suitable chemical trap environment is present. Buoyancy force is therefore a viable driving mechanism for basin-scale ore-forming hydrothermal fluid migration, and it is strong enough to lead to the genesis of supergiant SEDEX deposits like the Mount Isa deposit, Northern Australia.

  2. The dynamical masses, densities, and star formation scaling relations of Lyα galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Rhoads, James E.; Malhotra, Sangeeta; Richardson, Mark L. A.; McLinden, Emily M. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Finkelstein, Steven L. [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712 (United States); Fynbo, Johan P. U. [DARK Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Tilvi, Vithal S., E-mail: James.Rhoads@asu.edu [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics, Texas A and M University, College Station, TX 77843 (United States)

    2014-01-01

    We present the first dynamical mass measurements for Lyα galaxies at high redshift, based on velocity dispersion measurements from rest-frame optical emission lines and size measurements from Hubble Space Telescope imaging, for nine galaxies drawn from four surveys. We use these measurements to study Lyα galaxies in the context of galaxy scaling relations. The resulting dynamical masses range from 10{sup 9} to 10{sup 10} M {sub ☉}. We also fit stellar population models to our sample and use them to place the Lyα sample on a stellar mass versus line width relation. The Lyα galaxies generally follow the same scaling relation as star-forming galaxies at lower redshift, although, lower stellar mass fits are also acceptable in ∼1/3 of the Lyα galaxies. Using the dynamical masses as an upper limit on gas mass, we show that Lyα galaxies have unusually active star formation for their gas mass surface density. This behavior is consistent with what is observed in starburst galaxies, despite the typically smaller masses and sizes of the Lyα galaxy population. Finally, we examine the mass densities of these galaxies and show that their future evolution likely requires dissipational ('wet') merging. In short, we find that Lyα galaxies are low-mass cousins of larger starbursts.

  3. A review of the content and format of transgender-related webpages.

    Science.gov (United States)

    Horvath, Keith J; Iantaffi, Alex; Grey, Jeremy A; Bockting, Walter

    2012-01-01

    Transgender persons represent a highly diverse group of individuals who have been historically underserved, despite being disproportionately at risk for HIV (human immunodeficiency virus) and other health conditions. Despite the need for more research on transgender health issues, no review of online transgender-related resources has been conducted. The purpose of this study was to broadly characterize (1) the types of transgender-related webpages that appear as a result of keyword searches, and (2) the extent to which webpages differ in content and format depending on whether the intended audience for the webpage was transgender individuals, health professionals, or the general population. An online search using 28 keywords yielded 204 eligible webpages, of which 58% targeted transgendered individuals, 23% targeted health professionals, and 39% targeted the general public. The highest percentage of webpages appeared to be operated and/or created by transgender individuals or groups (46%), followed by for-profit businesses (17%). The majority of mental health (80%), HIV-related (89%), and primary care (100%) webpages targeted health professionals. Although various features are available that may increase user interest in and perceived credibility of a webpage, the results show that many of these features were underutilized. There appears to be significant opportunity to develop web resources that directly target unique subgroups within the transgender community to improve their health outcomes, increase the visibility of features that increase user interest and perceived credibility of webpages, and possibly train transgender individuals to seek relevant online information.

  4. Chemical and stable isotopic geochemical characteristics of ore-forming fluid of the Shizishan copper and gold ore-field, Tongling, China%铜陵狮子山铜金矿田成矿流体成分及稳定同位素地球化学

    Institute of Scientific and Technical Information of China (English)

    陆三明; 徐晓春; 谢巧勤; 楼金伟; 储国正; 熊亚平

    2007-01-01

    Shizishan ore-field is a nonferrous and noble metal ore-field which is most rich in copper and gold. There are many types of fluid inclusions in minerals of the deposits. The homogeneous temperatures and the salinities of the fluid inclusions in main mineralization stages have wide ranges, while the different types of the fluid inclusions existed together and their homogeneous temperatures are almost identical in the same mineralization stage, which indicates that the ore-forming process has great relation with the fluid boiling. The gas and liquid chemical compositions and the carbon, hydrogen and oxygen isotopic compositions of the fluid inclusions show that the ore-forming fluids of copper-gold deposits have the same characteristics and evolution tendency, which reflects that the ore-forming material mainly came from the magmatism. The stratigraphic component and the meteoric water may mix in oreforming fluids in the later mineralization stages. Furthermore, with the fall of the ore-forming temperature the ratios of water and rock decreased. The characteristics of chemical composition and carbon isotopic composition of fluid inclusions indicate that CH4 may play an important role for separating copper and gold in the ore-forming process.

  5. 内蒙古苏尼特左旗乌日尼图钨钼矿床地质特征及找矿标志%Geological characteristics and ore exploration marks of the Wurinitu tungsten-molybdenum deposit in Sunitezuo county,Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    王弢; 尚恒胜; 邵积东; 赵月明; 王守光; 李四娃

    2012-01-01

    乌日尼图钨钼矿床是近年来在国土资源大调查中发现的一个大型矿床.钨钼矿体主要产于燕山期细粒花岗岩与中下奥陶统乌宾敖包组砂板岩的外接触带中,矿体多呈脉状及透镜状,且明显受构造裂隙控制;矿床成矿在不同部位其矿化形式不同.在成矿母岩--燕山期细粒花岗岩中形成浸染状矿石;同时在与含钙质的板岩接触部位形成夕卡岩型矿石,在乌宾敖包组裂隙中形成热液脉型矿石.其中热液上侵与围岩接触处的细脉状矿床最为主要;矿体围岩蚀变发育,硅化、黄铁矿化与矿化关系最为密切;矿床深部钨钼矿石呈浸染状分布于细粒花岗岩中,后者为成矿母岩;矿床成因属广义的斑岩型矿床.%The large-size Wurinitu tungsten-molybdenum deposit is discovered in the Ercnhot-East Ujimqin, Inner Mongolia during implementation of Land resources survey program. The ore bodies occur mainly as veins and lenses in the outer contact zone between Yanshanian fine-grained granite and sandy slate of Middle-Lower Ordovician Wubinaobao formation and are obviously controled by tectonic fractures. Mineralization is varied spatially. The disseminated ore is in the Yanshanian fine-grained granite, the skarn ore at the contact between the fine-grained granite and calcareous slate and hydrothermal ore in the fractures of Wubinaobao formation. The hydrothermal ore vein is dominant. The wall rock alteration is well developed and silicification and pyritization are closely related to ore bodies. Genetically, the deposit is the generalized porphyry tungsten-molybdenum deposit.

  6. Arsenic bioleaching in medical realgar ore and arsenic- bearing ...

    African Journals Online (AJOL)

    medical realgar ore that allowed much higher leaching rates ... bioleaching behavior between mixed unadapted ... Acid drainage from copper mine, Zhongtiao Mountain, Shanxi,. China ..... during high temperature bioleaching of gold-bearing.

  7. ITABIRITE IRON ORE CONCENTRATION BY PNEUMATIC FLOTATION CELL

    Directory of Open Access Journals (Sweden)

    Angelo Quintiliano Nunes da Silva

    2015-06-01

    Full Text Available The main iron ore processing plants in Brazil operate through reverse cationic flotation. Many studies have been conducted in order to improve flotation efficiency by optimization process variables. The pneumatic flotation cell stands out due to the simplicity to and to the intense contact particle/bubble promoted by the pulp feeding system. In this study, laboratory scale and pilot were conducted using a sample of itabirite iron ore. The objectives are evaluating the performance of this device using low grade iron ore, and drawing a comparison with laboratory scale tests on conventional flotation cell. The results indicate the potential application of pneumatic flotation cell to the ore tested. Adjustments in the feed particle size and process optimizations can be performed on the concentrate, reaching Fe and SiO2 grades used by the industry

  8. Microstructure of bentonite in iron ore green pellets.

    Science.gov (United States)

    Bhuiyan, Iftekhar U; Mouzon, Johanne; Schröppel, Birgit; Kaech, Andres; Dobryden, Illia; Forsmo, Seija P E; Hedlund, Jonas

    2014-02-01

    Sodium-activated calcium bentonite is used as a binder in iron ore pellets and is known to increase strength of both wet and dry iron ore green pellets. In this article, the microstructure of bentonite in magnetite pellets is revealed for the first time using scanning electron microscopy. The microstructure of bentonite in wet and dry iron ore pellets, as well as in distilled water, was imaged by various imaging techniques (e.g., imaging at low voltage with monochromatic and decelerated beam or low loss backscattered electrons) and cryogenic methods (i.e., high pressure freezing and plunge freezing in liquid ethane). In wet iron ore green pellets, clay tactoids (stacks of parallel primary clay platelets) were very well dispersed and formed a voluminous network occupying the space available between mineral particles. When the pellet was dried, bentonite was drawn to the contact points between the particles and formed solid bridges, which impart strength to the solid compact.

  9. Carbothermal Upgrading of the Awaso Bauxite Ore using Waste ...

    African Journals Online (AJOL)

    Michael

    2015-06-01

    Jun 1, 2015 ... Ore using Waste Pure Water Sachets as Reductant”, Ghana Mining Journal, Vol. ... content) and the emergence of low grade bauxite with high iron oxide content calls for ... effects on the alumina extraction process (Lu et al.,.

  10. Measurement and Modelling of Blast Movement to Reduce Ore ...

    African Journals Online (AJOL)

    user

    growth both from new discoveries and the develop- ment of Subika ... search have developed innovative tools and tech- niques to .... 7 Histogram of Horizontal Blast Displace ment from All Five .... Better QA/QC along the ore/waste boundaries.

  11. Radioanalysis of RE enrichment of ion adsorption type RE ores

    CERN Document Server

    Zhao Shu Quan; Hu He Ping; Li Fu Sheng; Chen Ying Min; LiuShiMing

    2002-01-01

    Objective: To analyze the radioactivity in Rare Earth (RE) enrichment of ion adsorption type RE ores. Methods: Using HPGe-gamma spectrometer to analyze the activity ratio of gamma radionuclides in kind of samples, using FJ-2603 low background alpha, beta measurement apparatus to measure their total alpha and total beta activities, and using X-ray fluorescence spectrometer to analyze contents of La sub 2 O sub 3 and Y sub 2 O sub 3 , respectively. Results: HPGe gamma spectroscopy and X-ray fluorescence spectroscopy are simple, convenient and non-destructive methods of analyzing radionuclides and La sub 2 O sub 3 , Y sub 2 O sub 3 in RE enrichment of ion adsorption type RE ores, respectively. Conclusion: The basic data were provided for radiation protection and treatment of gas, liquid and solid waste in RE production of ion adsorption type RE ores; method and experience were provided for studying ion adsorption type RE ores

  12. Detection and Characterization of Ultrafine Fe-as-pb Colloids In Acid Rock Drainage Solution From An Ore Mine

    Science.gov (United States)

    Zänker, H.; Moll, H.; Richter, W.; Brendler, V.; Hennig, C.; Reich, T.; Kluge, A.; Hüttig, G.

    The processes of sulfide oxidation, water acidification and water mineralization in abandoned ore mines are closely associated with the existence of gangue fissures in the host rock that contain clay minerals and finely-divided sulfide ores. These fissures release highly mineralized, red-colored acid rock drainage (ARD) solutions which can be collected from pools in front of the fissures. ARD solution from an abandoned Zn-Pb-A g mine at Freiberg, Germany, (pH 2.7, sulfate concentration 411 mmol/l, Fe concentration 93,5 mmol/l) was nvestigated by photon correlation i spectroscopy, centrifugation, filtration, ultrafiltration, scanning electron microscopy, ICP-MS, AAS, ion chromatography, TOC analysis and X-ray absorption fine structure (EXAFS) spectroscopy. The question was if this ARD solution contains colloidal particles of the lower nanometer range or if it is particle-free after the common filtration through a 450-nm filter. We found that there is a small amount (about 20 mg/l) of submicron particles of about 100 nm in size. However, the major colloidal component was shown to be a population of ultrafine particles of less than 5 nm. The concentration of these particles is about 1 g/l. They consist of Fe, As and Pb compounds. According to EXAFS spectroscopy, their most probable mineralogical composition is a mixture of hydronium jarosite (HFe3(SO4)2(OH)6) and schwertmannite (ideally Fe8O8(OH)6SO 4). We also observed the formation of a relatively coarse precipitate of a similar mineralogy in the colloidal solution over a time span of months. The ultrafine colloids are obviously an intermediate in the formation process of the long-term precipitate. The arsenic is probably bound onto the ultrafine colloidal particles as a bidentate binuclear ars enate surface complex (inner-sphere complex). However, the transformation of the colloids into the more aggregated long-term precipitate leads to the incorporation of the arsenic into the interior of the iron hydroxy sulfate

  13. Star formation relations and CO spectral line energy distributions across the J-ladder and redshift

    Energy Technology Data Exchange (ETDEWEB)

    Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Leonidaki, I.; Xilouris, E. M. [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, GR-15236 Penteli (Greece); Weiß, A.; Henkel, C. [Max-Planck-Institut fur Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Zhang, Z.-Y. [UK Astronomy Technology Centre, Science and Technology Facilities Council, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Van der Werf, P.; Meijerink, R. [Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden (Netherlands); Aalto, S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Observatory, 43994 Onsala (Sweden); Armus, L.; Díaz-Santos, T. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Evans, A. S. [Astronomy Department, University of Virginia Charlottesville, VA 22904 (United States); Fischer, J. [Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Gao, Y. [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); González-Alfonso, E. [Universidad de Alcala de Henares, Departamento de Fśica, Campus Universitario, E-28871 Alcalá de Henares, Madrid (Spain); Harris, A. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Naylor, D. A. [Institute for Space Imaging Science, Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada); Smith, H. A. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Spaans, M., E-mail: t.greve@ucl.ac.uk [Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); and others

    2014-10-20

    We present FIR [50-300 μm]–CO luminosity relations (i.e., log L{sub FIR}=αlog L{sub CO}{sup ′}+β) for the full CO rotational ladder from J = 1-0 up to J = 13-12 for a sample of 62 local (z ≤ 0.1) (Ultra) Luminous Infrared Galaxies (LIRGs; L {sub IR[8-1000} {sub μm]} > 10{sup 11} L {sub ☉}) using data from Herschel SPIRE-FTS and ground-based telescopes. We extend our sample to high redshifts (z > 1) by including 35 submillimeter selected dusty star forming galaxies from the literature with robust CO observations, and sufficiently well-sampled FIR/submillimeter spectral energy distributions (SEDs), so that accurate FIR luminosities can be determined. The addition of luminous starbursts at high redshifts enlarge the range of the FIR–CO luminosity relations toward the high-IR-luminosity end, while also significantly increasing the small amount of mid-J/high-J CO line data (J = 5-4 and higher) that was available prior to Herschel. This new data set (both in terms of IR luminosity and J-ladder) reveals linear FIR–CO luminosity relations (i.e., α ≅ 1) for J = 1-0 up to J = 5-4, with a nearly constant normalization (β ∼ 2). In the simplest physical scenario, this is expected from the (also) linear FIR–(molecular line) relations recently found for the dense gas tracer lines (HCN and CS), as long as the dense gas mass fraction does not vary strongly within our (merger/starburst)-dominated sample. However, from J = 6-5 and up to the J = 13-12 transition, we find an increasingly sublinear slope and higher normalization constant with increasing J. We argue that these are caused by a warm (∼100 K) and dense (>10{sup 4} cm{sup –3}) gas component whose thermal state is unlikely to be maintained by star-formation-powered far-UV radiation fields (and thus is no longer directly tied to the star formation rate). We suggest that mechanical heating (e.g., supernova-driven turbulence and shocks), and not cosmic rays, is the more likely source of energy for

  14. Vertical mineralization interval and forecast of the position of an ore-body in the Alšar Sb-As-Tl deposit, FYR Macedonia

    Directory of Open Access Journals (Sweden)

    Jelenković Rade

    2011-01-01

    Full Text Available Establishing a vertical interval of mineralization is a complex geological task based on the knowledge of many parameters and quantities that describe the genesis of an ore deposit. It is particularly important to know the time and the primary depth of the formation of an ore-body and its recent position. The establishment of the vertical mineralization interval is considered in this work on the example of the Alšar Sb-As-Tl mineral deposit. The research methods used were geomorphological analysis (the principal exploration method, measurement of cosmogenic radioactive (10Be, 26Al and stable (3He, 21Ne nuclides to determine the erosion velocity (control method and comparison of the obtained results with the geological exploration data from operative mine workings. A detailed geological study of the formation of the Alšar deposit preceded the research. The research data are the following: depth interval of the ore-body is 10-50 m below the present ground surface; average level of erosion in the Alšar deposit area is 20-80 m over a period of 106 years (Ma, or about 100-400 m from the beginning of the volcanic activity to the present day (≈5 Ma; thickness of the eroded rock complex over the ore bodies from the beginning of the hydrothermal alteration and the formation of ore bodies (4.31 Ma to the present is ≥150 m (Crven dol, or ≥230 m (central deposit; the palaeointerval of the formation of the ore-body is 230 m (200-430 m; and, finally, the potentially mineralized interval is deep, from 10 m to 280 m below the surface.

  15. Aging Behavior of the Viton® Fluoroelastomer O-Rings in the 9975 Shipping Package

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W.; Mcwilliams, A.; Skidmore, E.

    2015-06-09

    relationship between CSR behavior and leak-tight performance has not been established for this design, the CSR predictions for this O-ring are conservative relative to leak-tight performance to date.