Sample records for epithermal gold-silver mineralization

  1. Physical setting and characteristics of high-sulfidation epithermal gold-silver deposits of the Andes and controls on mineralizing processes

    Bissig, T.


    Gold and silver mineralization in the vast majority of Andean high-sulfidation epithermal deposits occurs 200-700 m below low relief but high elevation landforms situated at 3500 to 5200 m a.s.l. Stratovolcanoes, in contrast, are uncommon ore hosts. Most deposits are middle Miocene and younger and include the California-Vetas mining district ( Colombia), Quimsaocha (Ecuador), Yanacocha, Lagunas Norte, Pierina, Cerro de Pasco (Peru), Pascua-Lama, Veladero, El Indio and Tambo (Chile/Argentina), jointly accounting for > 130 Moz Au resources. Older examples are restricted to the Atacama Desert and include the middle Eocene El Guanaco and El Hueso and the late Oligocene La Coipa deposits. Mineralization coincides with transpressional tectonics and surface uplift. Volcanic rocks coincident with mineralization are volumetrically restricted or absent, although dacitic domes are important at, e.g., Yanacocha, Lagunas Norte and La Coipa. Mineralization is typically located near the backscarps of pediments or heads of valleys incising into the high-elevation, low relief surfaces. In the California-Vetas district and El Indio belt, hydrothermal alunite ages become generally younger upstream along the incising valleys, indicating that the focus of mineralization migrated upstream over time. The lowering of the water table and reduction of hydrostatic and lithostatic pressure at locations where erosion rates are highest are believed to facilitate boiling and mixing of magmatic with meteoric fluids, ultimately enhancing hydrothermal activity and ore deposition. The host rock composition, permeability and location of the water table control the distribution of alteration zones and ore. The surface near steam-heated zone can attain a thickness of several hundred meters in dry climates but is typically less than 20-50 m thick in humid climatic zones. Felsic to intermediate volcanic rocks are the most common ore-hosts but high-sulfidation epithermal mineralization can be hosted in

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

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


    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

  3. Magmatism and Epithermal Gold-Silver Deposits of the Southern Ancestral Cascade Arc, Western Nevada and Eastern California

    John, David A.; du Bray, Edward A.; Henry, Christopher D.; Vikre, Peter


    hornblende, biotite, and pyroxene phenocrysts. Seven epithermal gold-silver deposits with >1 Moz gold production, several large elemental sulfur deposits, and many large areas (10s to >100 km2) of hydrothermally altered rocks are present in the southern ancestral arc, especially south of latitude 40°N. These deposits are principally hosted by intermediate to silicic lava dome complexes; only a few deposits are associated with mafic- to intermediate-composition stratovolcanoes. Large deposits are most abundant and well developed in volcanic fields whose evolution spanned millions of years. Most deposits are hundreds of thousands to several million years younger than their host rocks, although some quartz-alunite deposits are essentially coeval with their host rocks. Variable composition and thickness of crustal basement is the primary control on mineralization along the length of the southern ancestral arc; most deposits and large alteration zones are localized in basement rock terranes with a strong continental affinity, either along the edge of the North American craton (Goldfield, Tonopah) or in an accreted terrane with continental affinities (Walker Lake terrane; Aurora, Bodie, Comstock Lode, Paradise Peak). Epithermal deposits and quartz-alunite alteration zones are scarce to absent in the northern part of the ancestral arc above an accreted island arc (Black Rock terrane) or unknown basement rocks (Modoc Plateau). Walker Lane structures and areas that underwent large magnitude extension during the Late Cenozoic (areas with Oligocene-early Miocene volcanic rocks dipping >40°) do not provide regional control on mineralization. Instead, these features may have served as local-scale conduits for mineralizing fluids.

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

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


    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

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

    Wei Min


    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.

  6. Miocene and early Pliocene epithermal gold-silver deposits in the northern Great Basin, western United States: Characteristics, distribution, and relationship to Magmatism

    John, D.A.


    -sulfidation gold-silver and porphyry copper-gold deposits are affiliated with the western andesite assemblage and include the Comstock Lode, Tonopah, Goldfield, Aurora, Bodie, Paradise Peak, and Rawhide deposits. Low-sulfidation Au-Ag deposits in the bimodal assemblage formed under relatively low oxygen and sulfur fugacities and have generally low total base metal (Cu + Pb + Zn) contents, low Ag/Au ratios, and notably high selenide mineral contents compared to temporally equivalent low-sulfidation deposits in the western andesite assemblage. Petrologic studies suggest that these differences may reflect variations in the magmatic-tectonic settings of the associated magmatic assemblages-deposits in the western andesite assemblage formed from oxidized, water-rich, subduction-related calc-alkaline magmas, whereas deposits in the bimodal assemblage were associated with reduced, water-poor tholeiitic magmas derived from the lithospheric mantle during continental extension. The contrasting types and characteristics of epithermal deposits and their affinities with associated igneous rocks suggest that a genetic relationship is present between these Au-Ag deposits and their temporally associated magmatism, although available data do not prove this relationship for most low-sulfidation deposits.

  7. Gold-silver-tellurium mineral assemblages in different ore styles of the Southern Urals VHMS deposits

    Maslennikov, V. V.; Zaykov, V. V.; Maslennikova, S. P.; Tesalina, S. G.; Herrington, R. J.; Buschmann, B.; Becker, K.; Petersen, S.; Orgeval, J. J.; Leistel, M.


    VMS deposits of the South Urals generally show a continuum in degradation and reworking ranging from pristine steep-sided hydrothermal sulphide mounds to deposits dominated by layered strata of clastic sulphides. Four different deposits with varying degrees of degradation in order of increased reworking: (Yaman-Kasy longrightarrow Molodezhnoe longrightarrow Alexandrinskoe longrightarrow Balta-Tau) have been ranged. The influence of sulphide mound destruction and of sea-floor alteration on mineral assemblages was investigated In the pristine Yaman-Kasy sulphide mound gold and silver occur as altaite+tellurium+hessite-stuetzite+sylvanite and later galena+native gold+pyrite assemblages in chalcopyrite+isocubanite-rich linings of former chimney conduits. Chalcopyrite-dominated conduit fragments in clastic ore facies contain native tellurium+gold intergrowths. In the weakly reworked Molodezhnoe deposit gold-silver assemblages only occur in sea-floor altered clastic sulphides on the slope of massive sulphide mounds in bornite- and tennantite-rich ores in association with Cu-Ag sulfides such as jalpaite, mckinstryite, and stromeyerite and rare Au-Ag-tellurides (petzite). The Alexandrinskoe deposit is dominated by clastic ores and here native gold and rare hessite occur together with galena in tennantite-sphalerite-dominated veins of the footwall as well as in drusy sphalerite forming conduits of vent chimneys. An assemblage of electrum+galena+tennantite was observed in secondary chalcopyrite in the outer walls of chimneys. Native gold+stromeyerite are common in bornite-rich clastic sulphides while an assemblage of Ag-sulphosalts+electrum is common in barite-rich ores. In the reworked Balta-Tau deposit Ag-sulphosalts+electrum-kustelite occur often together with tennantite+galena+barite banded ores. Gold-silver-telluride mineralisation in these VMS deposits changes with degree of reworking from Au-tellurides, and native gold+galena+pyrite in pristine sulphide mounds to

  8. Epithermal Gold Mineralization in Chinese Tianshan Province


    Tianshan is a part of the complex system of orogenic belts of Phanerozoic in Central Asia. In the northwestern Chinese Tianshan, Borohoro range, the major metallogenic belt in this area is situated between the Yili block and Keguqinshan-Sairim uplift. The intra-arc basins resulting from southward subduction of the Junggar plate and accompanying volcanism are the essential factors for the formation of the hydrothermal system that caused gold mineralization. The adularia-sericite-style epithermal Arxi gold deposit formed in an extensional tectonic setting. In the eastern Tianshan, post-orogenic magmatism resulted in a hydrothermai system that produced the epithermai Xitan gold deposit. Both gold deposits are related to local extensional setting, although differences exist in their timing and location.

  9. Characteristics that distinguish types of epithermal deposits

    Hayba, D.O.; Foley, N.K.; Heald-Wetlaufer, P.


    Three distinctive groupings of epithermal deposits were recognized from a literature study of fifteen well-described precious- and base-metal epithermal districts, supplemented by L. J. Buchanan's 1981 compilation of data from 47 less completely documented deposits. The three groups are distinguished primarily by the type of alteration and the sulfur fugacity indicated by the vein mineral assemblage. Additional discriminating criteria include composition of the host rock, timing of ore deposition relative to emplacement of the host, and relative abundances of gold, silver, and base metals.

  10. Fluid chemistry evolution and mineral deposition in the main-stage Creede epithermal system

    Plumlee, G.S.


    This paper presents results of chemical speciation and reaction path calculations that model fluid chemistry evolution and ore deposition in the main-stage Creede, Colorado, epithermal system. An extensive geologic, mineralogic, and geochemical framework for mineralization has been developed by many researchers for the central and southern district vein systems (OH and P veins; central and southern Amethyst and Bulldog Mountain vein systems) and is used to constrain and guide the modeling presented in this paper. Modeling results for Creede and other epithermal fluid compositions show that epithermal ore grades, mineral assemblages, and mineral zoning patterns are strongly influenced by shallow hydrologic processes such as boiling and fluid mixing. As a result, epithermal mineral assemblages and zoning patterns can be used to reconstruct the paleohydrology of the hydrothermal systems from which they were deposited, and thus provide useful tools for epithermal ore exploration -from Author

  11. Geochemical characteristics of igneous rocks associated with epithermal mineral deposits—A review

    du Bray, Edward A.


    Newly synthesized data indicate that the geochemistry of igneous rocks associated with epithermal mineral deposits varies extensively and continuously from subalkaline basaltic to rhyolitic compositions. Trace element and isotopic data for these rocks are consistent with subduction-related magmatism and suggest that the primary source magmas were generated by partial melting of the mantle-wedge above subducting oceanic slabs. Broad geochemical and petrographic diversity of individual igneous rock units associated with epithermal deposits indicate that the associated magmas evolved by open-system processes. Following migration to shallow crustal reservoirs, these magmas evolved by assimilation, recharge, and partial homogenization; these processes contribute to arc magmatism worldwide.Although epithermal deposits with the largest Au and Ag production are associated with felsic to intermediate composition igneous rocks, demonstrable relationships between magmas having any particular composition and epithermal deposit genesis are completely absent because the composition of igneous rock units associated with epithermal deposits ranges from basalt to rhyolite. Consequently, igneous rock compositions do not constitute effective exploration criteria with respect to identification of terranes prospective for epithermal deposit formation. However, the close spatial and temporal association of igneous rocks and epithermal deposits does suggest a mutual genetic relationship. Igneous systems likely contribute heat and some of the fluids and metals involved in epithermal deposit formation. Accordingly, deposit formation requires optimization of source metal contents, appropriate fluid compositions and characteristics, structural features conducive to hydrothermal fluid flow and confinement, and receptive host rocks, but not magmas with special compositional characteristics.

  12. Geology of the Ivanhoe Hg-Au district, northern Nevada: Influence of Miocene volcanism, lakes, and active faulting on epithermal mineralization

    Wallace, A.R.


    massive rhyolites and Paleozoic quartzites at deeper levels, and these mineralized zones possibly represent the feeder zones for the higher-level deposits. Fluctuations in the ground-water table locally produced hydrothermal oxidation of the near-surface mercury and disseminated gold deposits. The locus of mineralization shifted with time, moving south and east from its inception point in the west-central part of the district. Thus, although mineralization in the district took place during a span of 300,000 years, the duration of mineralization at any one place probably was much shorter. The low-sulfidation deposits of the Ivanhoe district formed at the same time and under similar conditions as those in the nearby Midas district, 15 km to the northwest, which includes the large, high-grade Ken Snyder gold-silver epithermal vein deposit. The exposures in the Ivanhoe district are interpreted to represent the near-surface example of the paleosurface that originally was present above the Midas mineralizing system. The resulting combined Ivanhoe-Midas model provides an exploration guide for epithermal deposits in similar geologic environments in northern Nevada.

  13. Gold, Silver and Bronze Citations.

    American School & University, 2003


    Presents the gold, silver, and bronze winners of a competition, which judged the most outstanding learning environments at educational institutions nationwide. Jurors spent two days reviewing projects, focusing on concepts and ideas that made them exceptional. For each citation, the article offers information on the firm, client, total area, total…

  14. Epithermal mineralization controlled by synextensional magmatism in the Guazapares Mining District of the Sierra Madre Occidental silicic large igneous province, Mexico

    Murray, Bryan P.; Busby, Cathy J.


    We show here that epithermal mineralization in the Guazapares Mining District is closely related to extensional deformation and magmatism during the mid-Cenozoic ignimbrite flare-up of the Sierra Madre Occidental silicic large igneous province, Mexico. Three Late Oligocene-Early Miocene synextensional formations are identified by detailed volcanic lithofacies mapping in the study area: (1) ca. 27.5 Ma Parajes formation, composed of silicic outflow ignimbrite sheets; (2) ca. 27-24.5 Ma Témoris formation, consisting primarily of locally erupted mafic-intermediate composition lavas and interbedded fluvial and debris flow deposits; (3) ca. 24.5-23 Ma Sierra Guazapares formation, composed of silicic vent to proximal ignimbrites, lavas, subvolcanic intrusions, and volcaniclastic deposits. Epithermal low-to intermediate-sulfidation, gold-silver-lead-zinc vein and breccia mineralization appears to be associated with emplacement of Sierra Guazapares formation rhyolite plugs and is favored where pre-to-synvolcanic extensional structures are in close association with these hypabyssal intrusions. Several resource areas in the Guazapares Mining District are located along the easternmost strands of the Guazapares Fault Zone, a NNW-trending normal fault system that hosts most of the epithermal mineralization in the mining district. This study describes the geology that underlies three of these areas, which are, from north to south: (1) The Monte Cristo resource area, which is underlain primarily by Sierra Guazapares formation rhyolite dome collapse breccia, lapilli-tuffs, and fluvially reworked tuffs that interfinger with lacustrine sedimentary rocks in a synvolcanic half-graben bounded by the Sangre de Cristo Fault. Deposition in the hanging wall of this half-graben was concurrent with the development of a rhyolite lava dome-hypabyssal intrusion complex in the footwall; mineralization is concentrated in the high-silica rhyolite intrusions in the footwall and along the

  15. Geology and hydrothermal alteration at the Madh adh Dhahab epithermal precious-metal deposit, Kingdom of Saudi Arabia

    Doebrich, J.L.; LeAnderson, J.P.


    Mahd adh Dhahab is a late Precambrian epithermal gold-silver-base metal deposit located in the west-central part of the Arabian Shield. North-trending quartz veins containing base and precious metals cut an east-striking, north-dipping homoclinal sequence of volcanic, volcaniclastic, and epiclastic rocks of intermediate to felsic composition. Ore was localized where the veins cut competent, coarse-grained, fragmental units directly below incompetent and impermeable tuff units. The proximity of an epizonal rhyolite porphyry stock to these contacts also was important in localizing ore. Ore minerals include native gold and silver, gold-silver tellurides, chalcopyrite, sphalerite, and minor galena, and five stages of mineralization have been identified.

  16. Evidence for rapid epithermal mineralization and coeval bimodal volcanism, Bruner Au-Ag property, NV USA

    Baldwin, Dylan

    The character of Au-Ag mineralization and volcanic/hydrothermal relationships at the underexplored Miocene-age Bruner low-sulfidation epithermal Au-Ag deposit are elucidated using field and laboratory studies. Bruner is located in central Nevada within the Great Basin extensional province, near several major volcanic trends (Western Andesite, Northern Nevada Rift) associated with world-class Miocene-age epithermal Au-Ag provinces. Despite its proximity to several >1 Moz Au deposits, and newly discovered high-grade drill intercepts (to 117 ppm Au/1.5m), there is no published research on the deposit, the style of mineralization has not been systematically characterized, and vectors to mineralization remain elusive. By investigating the nature of mineralization and time-space relationships between volcanic/hydrothermal activity, the deposit has been integrated into a regional framework, and exploration targeting improved. Mineralization occurs within narrow quartz + adularia +/- pyrite veins that manifest as sheeted/stockwork zones, vein swarms, and rare 0.3-2 m wide veins hosted by two generations of Miocene high-K, high-silica rhyolite flow dome complexes overlying an andesite flow unit. The most prominent structural controls on veining are N­striking faults and syn-mineral basalt/rhyolite dikes. Productive veins have robust boiling indicators (high adularia content, bladed quartz after calcite, recrystallized colloform quartz bands), lack rhythmic banding, and contain only 1-2 stages; these veins overprint, or occur separately from another population of barren to weakly mineralized rhythmically banded quartz-only veins. Ore minerals consist of coarse Au0.5Ag 0.5 electrum, fine Au0.7Ag0.3 electrum, acanthite, uytenbogaardtite (Ag3AuS2) and minor embolite Ag(Br,Cl). Now deeply oxidized, veins typically contain geothermal circulation along N-S structural fabric driven by heat from rhyolite domes; ~16.34 Ma, emplacement of NW trending basalt dikes, followed by violent

  17. Origin of epithermal Ag-Au-Cu-Pb-Zn mineralization in Guanajuato, Mexico

    Mango, Helen; Arehart, Greg; Oreskes, Naomi; Zantop, Half


    The Guanajuato epithermal district is one of the largest silver producers in Mexico. Mineralization occurs along three main vein systems trending dominantly northwest-southeast: the central Veta Madre, the La Luz system to the northwest, and the Sierra system to the east. Mineralization consists dominantly of silver sulfides and sulfosalts, base metal sulfides (mostly chalcopyrite, galena, sphalerite, and pyrite), and electrum. There is a broad zonation of metal distribution, with up to 10 % Cu+Pb+Zn in the deeper mines along the northern and central portions of the Veta Madre. Ore occurs in banded veins and breccias and as stockworks, with gangue composed dominantly of quartz and calcite. Host rocks are Mesozoic sedimentary and intrusive igneous rocks and Tertiary volcanic rocks. Most fluid inclusion homogenization temperatures are between 200 and 300 °C, with salinities below 4 wt.% NaCl equivalent. Fluid temperature and salinity decreased with time, from 290 to 240 °C and from 2.5 to 1.1 wt.% NaCl equivalent. Relatively constant fluid inclusion liquid-to-vapor ratios and a trend of decreasing salinity with decreasing temperature and with increasing time suggest dilution of the hydrothermal solutions. However, evidence of boiling (such as quartz and calcite textures and the presence of adularia) is noted along the Veta Madre, particularly at higher elevations. Fluid inclusion and mineralogical evidence for boiling of metal-bearing solutions is found in gold-rich portions of the eastern Sierra system; this part of the system is interpreted as the least eroded part of the district. Oxygen, carbon, and sulfur isotope analysis of host rocks, ore, and gangue minerals and fluid inclusion contents indicate a hydrothermal fluid, with an initial magmatic component that mixed over time with infiltrating meteoric water and underwent exchange with host rocks. Mineral deposition was a result of decreasing activities of sulfur and oxygen, decreasing temperature, increasing p

  18. Lithologic controls on mineralization at the Lagunas Norte high-sulfidation epithermal gold deposit, northern Peru

    Cerpa, Luis M.; Bissig, Thomas; Kyser, Kurt; McEwan, Craig; Macassi, Arturo; Rios, Hugo W.


    The 13.1-Moz high-sulfidation epithermal gold deposit of Lagunas Norte, Alto Chicama District, northern Peru, is hosted in weakly metamorphosed quartzites of the Upper Jurassic to Lower Cretaceous Chimú Formation and in overlying Miocene volcanic rocks of dacitic to rhyolitic composition. The Dafne and Josefa diatremes crosscut the quartzites and are interpreted to be sources of the pyroclastic volcanic rocks. Hydrothermal activity was centered on the diatremes and four hydrothermal stages have been defined, three of which introduced Au ± Ag mineralization. The first hydrothermal stage is restricted to the quartzites of the Chimú Formation and is characterized by silice parda, a tan-colored aggregate of quartz-auriferous pyrite-rutile ± digenite infilling fractures and faults, partially replacing silty beds and forming cement of small hydraulic breccia bodies. The δ34S values for pyrite (1.7-2.2 ‰) and digenite (2.1 ‰) indicate a magmatic source for the sulfur. The second hydrothermal stage resulted in the emplacement of diatremes and the related volcanic rocks. The Dafne diatreme features a relatively impermeable core dominated by milled slate from the Chicama Formation, whereas the Josefa diatreme only contains Chimú Formation quartzite clasts. The third hydrothermal stage introduced the bulk of the mineralization and affected the volcanic rocks, the diatremes, and the Chimú Formation. In the volcanic rocks, classic high-sulfidation epithermal alteration zonation exhibiting vuggy quartz surrounded by a quartz-alunite and a quartz-alunite-kaolinite zone is observed. Company data suggest that gold is present in solid solution or micro inclusions in pyrite. In the quartzite, the alteration is subtle and is manifested by the presence of pyrophyllite or kaolinite in the silty beds, the former resulting from relatively high silica activities in the fluid. In the quartzite, gold mineralization is hosted in a fracture network filled with coarse alunite

  19. Induced polarization imaging applied to exploration for low-sulfidation epithermal Au-Ag deposits, Seongsan mineralized district, South Korea

    Han, Man-Ho; Shin, Seung Wook; Park, Samgyu; Cho, Seong-Jun; Kim, Jung-Ho


    The determination of mineralization boundaries during mineral exploration for undiscovered low-sulfidation epithermal Au-Ag deposits is a significant challenge because of the extensive survey areas required. Induced polarization (IP) imaging is an effective geophysical technique for the detection of sulfides or clay. Thus, this method is considered useful to determine the boundaries of subsurface mineralization and hydrothermal alteration associated with epithermal deposits. We used 2D and 3D IP imaging to define the silicification and mineralization boundaries of the Moisan deposit in the Seongsan mineralized district, which is geologically well-known. The boundaries of the silicification zone were defined by high resistivity values of 600 Ω-m, and those of the mineralization zone were defined by high global chargeability values of 3 mV V-1. The continuity of the high resistivity anomaly corresponded well to the silicification (quartz veins) exposed in outcrop. In addition, it is geologically reasonable that the chargeability anomaly, ⩾3 mV V-1, associated with the mineralization/hydrothermal alteration zone was concentrated at near-surface depths, and extensively surrounding the resistivity anomaly, ⩾600 Ω-m, associated with the silicification zone.

  20. The genesis of the slab window-related Arzular low-sulfidation epithermal gold mineralization (eastern Pontides, NE Turkey

    Enver Akaryalı


    Full Text Available The Arzular mineralization is one of the best examples of epithermal gold deposits in the eastern Pontides orogenic belt. The mineralization is hosted by the subduction-related basaltic andesites and is mainly controlled by E–W and NE–SW trending fracture zones. The main ore minerals are galena, sphalerite, pyrite, chalcopyrite, tetrahedrite and gold. Homogenization temperatures of fluid inclusions are between 130 and 295 °C for quartz and between 90 and 133 °C for sphalerite. Sulphur isotope values obtained from pyrite, galena and sphalerite vary between −1.2‰ and 3‰, indicating that sulphur belongs to magmatic origin and was derived from the Lutetian non-adakitic granitic intrusions in the region. Oxygen isotope values are between 15.0‰ and 16.7‰, and hydrogen isotope values are between −87‰ and −91‰. The sulphur isotope thermometer yielded temperatures in the range of 244–291 °C for the ore formation. Our results support the hypothesis that the Arzular mineralization is a low-sulfidation epithermal gold deposit associated with non-adakitic subduction-related granitic magmas that were generated by slab window-related processes in a south-dipping subduction zone during the Lutetian.

  1. The transition from porphyry- to epithermal-style gold mineralization at Ladolam, Lihir Island, Papua New Guinea: a reconnaissance study

    Müller, Daniel; Kaminski, Klaus; Uhlig, Stephan; Graupner, Torsten; Herzig, Peter M.; Hunt, Steve


    The exceptionally large gold resource at Ladolam (>1,300 metric tons of gold), Lihir Island, resulted from the transition of an early-stage, low-grade porphyry gold system to a low-sulfidation epithermal gold event. This transition was probably triggered by rapid decompression during the partial slope failure of Luise stratovolcano and accompanied by the ingress of seawater. The original porphyry stage is indicated by remnant hydrothermal breccia clasts of strongly biotite-magnetite altered monzodiorite with disseminated pyrite ± chalcopyrite and poorly developed pyrite ± quartz stockwork veins. The breccias are overprinted by biotite-magnetite alteration and their matrix is strongly mineralized with disseminated auriferous pyrite. The breccias are cut by late-stage epithermal quartz-chalcedony-illite-adularia-pyrite veins and associated illite-adularia alteration that locally contain bonanza gold grades of up to 120 g/t. Isotope data suggest a magmatic source of sulfur in the gold-bearing fluids at Ladolam. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at

  2. Metallogeny of the Gold Quadrilateral: style and characteristics of epithermal - subvolcanic mineralized structures, South Apuseni Mts., Romania

    S̡erban-Nicolae Vlad


    Full Text Available The Romanian territory contains numerous ore deposits mined since pre-Roman times. An assessment of historical gold production of the Gold Quadri-lateral (GQ yielded a total estimate of 55.7 Moz of gold throughout an area of 2400 km2. Interpreted in terms of mineralization density this is 23,208 oz of gold/ km2. The geological setting of the GQ is represented mainly by Tertiary (14.7 My to 7.4 My calc-alkaline volcano-plutonic complexes of intermediate character in sedimentary basins of molasse type. These basins are tectonically controlled by NW-SE lineation across early Alpine magmatic products, i.e. subduction related Jurassic-Lower Cretaceous igneous association (island arc ophiolites and granitoids and Upper Cretaceous igneous association (banatites. The Tertiary magmatism is associated with extensional tectonics caused by NE escape of the Pannonian region during Upper Oligocene-Lower Miocene times. As a result of tectono-magmatic and mineralization-alteration characteristics, two metallogenetical types were separated in the GQ, i.e. calc-alkaline andesitic (CAM and sub-alkaline rhyodacitic (SRM. Both develop almost entirely low-sulfidation type of Au epithermal mineralization. However, two subtypes, -rich in sulfide (2-7% and -poor in sulfide (7-20% were delineated and correlated with CAM type and SRM type respectively. Furthermore, CAM is connected at deeper levels with Cu-Au+/-Mo porphyry systems in contrast with SRM, which is a non-porphyry environment. The Brad-Săcărâmb district contains mainly CAM type andesitic structures. It is a porphyry environment with epithermal low-sulfidation-rich sulfide vein halo (Barza, Troiţa-Bolcana deposits. However, a few SRM type patterns, such as Măgura Ţebii, Băiţa-Crăciuneşti and Săcărâmb, deposits exhibit Au-Ag-Te low-sulfidation-poor sulfide epithermal vein halo. The Zlatna-Stănija district exhibits similar characteristics, with Au-Ag+/-Pb, Zn veins in Cu-Au subvolcanic

  3. The Stypsi-Megala Therma porphyry-epithermal mineralization, Lesvos Island, Greece: new mineralogical and geochemical data

    Periferakis, Argyrios; Voudouris, Panagiotis; Melfos, Vasilios; Mavrogonatos, Constantinos; Alfieris, Dimitrios


    anomalies to those previously reported by [1] but also provide additional information in a series of elements: Cu (up to 843 ppm), Mo (up to 76 ppm), Au (up to 120 ppb), Pb (up to 339ppm), Zn (up to 815ppm), Se (up to 10ppm), Te (up to 4 ppm), Bi (up to 4 ppm) and Sn (up to 23 ppm). The Lesvos Island may be interpreted as the westward extension of the Eocene-Miocene Biga peninsula Cu-Au porphyry belt, with potential for future discoveries of Cu-Mo±Au deposits in the Aegean area. [1] Voudouris P, Alfieris D (2005) New porphyry-Cu±Mo occurrences in northeastern Aegean/Greece: Ore mineralogy and transition to epithermal environment. In: Mao J, Bierlein FP (eds) Mineral deposit research: Meeting the global challenge. Springer Verlag, 473-476; [2] Kontis E, Kelepertsis AE, Skounakis S (1994) Geochemistry and alteration facies associated with epithermal precious metal mineralization in an active geothermal system, northern Lesvos, Greece. Min Deposita, 29:430-433; [3] Muntean JL, Einaudi MT (2000) Porphyry Gold Deposits of the Refugio District, Maricunga Belt, Northern Chile. Econ. Geology, 95, 1445-1472.

  4. Geochemistry, geochronology, mineralogy, and geology suggest sources of and controls on mineral systems in the southern Toquima Range, Nye County, Nevada; with geochemistry maps of gold, silver, mercury, arsenic, antimony, zinc, copper, lead, molybdenum, bismuth, iron, titanium, vanadium, cobalt, beryllium, boron, fluorine, and sulfur; and with a section on lead associations, mineralogy and paragenesis, and isotopes

    Shawe, Daniel R.; Hoffman, James D.; Doe, Bruce R.; Foord, Eugene E.; Stein, Holly J.; Ayuso, Robert A.


    Geochemistry maps showing the distribution and abundance of 18 elements in about 1,400 rock samples, both mineralized and unmineralized, from the southern Toquima Range, Nev., indicate major structural and lithologic controls on mineralization, and suggest sources of the elements. Radiometric age data, lead mineralogy and paragenesis data, and lead-isotope data supplement the geochemical and geologic data, providing further insight into timing, sources, and controls on mineralization. Major zones of mineralization are centered on structural margins of calderas and principal northwest-striking fault zones, as at Round Mountain, Manhattan, and Jefferson mining districts, and on intersections of low-angle and steep structures, as at Belmont mining district. Paleozoic sedimentary rocks, mostly limestones (at Manhattan, Jefferson, and Belmont districts), and porous Oligocene ash-flow tuffs (at Round Mountain district) host the major deposits, although all rock types have been mineralized as evidenced by numerous prospects throughout the area. Principal mineral systems are gold-silver at Round Mountain where about 7 million ounces of gold and more than 4 million ounces of silver has been produced; gold at Gold Hill in the west part of the Manhattan district where about a half million ounces of gold has been produced; gold-mercury-arsenic-antimony in the east (White Caps) part of the Manhattan district where a few hundred thousand ounces of gold has been produced; and silver-lead-antimony at Belmont where more than 150,000 ounces of silver has been produced. Lesser amounts of gold and silver have been produced from the Jefferson district and from scattered mines elsewhere in the southern Toquima Range. A small amount of tungsten was produced from mines in the granite of the Round Mountain pluton exposed east of Round Mountain, and small amounts of arsenic, antimony, and mercury have been produced elsewhere in the southern Toquima Range. All elements show unique

  5. Antibacterial properties and mechanisms of gold-silver nanocages

    Wang, Yulan; Wan, Jiangshan; Miron, Richard J.; Zhao, Yanbin; Zhang, Yufeng


    Despite the number of antibiotics used in routine clinical practice, bacterial infections continue to be one of the most important challenges faced in humans. The main concerns arise from the continuing emergence of antibiotic-resistant bacteria and the difficulties faced with the pharmaceutical development of new antibiotics. Thus, advancements in the avenue of novel antibacterial agents are essential. In this study, gold (Au) was combined with silver (Ag), a well-known antibacterial material, to form silver nanoparticles producing a gold-silver alloy structure with hollow interiors and porous walls (gold-silver nanocage). This novel material was promising in antibacterial applications due to its better biocompatibility than Ag nanoparticles, potential in photothermal effects and drug delivery ability. The gold-silver nanocage was then tested for its antibacterial properties and the mechanism involved leading to its antibacterial properties. This study confirms that this novel gold-silver nanocage has broad-spectrum antibacterial properties exerting its effects through the destruction of the cell membrane, production of reactive oxygen species (ROS) and induction of cell apoptosis. Therefore, we introduce a novel gold-silver nanocage that serves as a potential nanocarrier for the future delivery of antibiotics.

  6. Ore mineralogy and textural zonation in the world-class epithermal Waihi Vein System, Hauraki Goldfield

    Mauk, Jeffrey L.; Skinner, Erin G; Fyfe, Sarah J; Menzies, Andrew H; Lowers, Heather A.; Koenig, Alan E.


    The Waihi district in the Hauraki Goldfield of New Zealand contains adularia-sericite epithermal gold-silver veins that have produced more than 7.7 Moz gold. The outermost veins of the district (Martha, Favona, Moonlight, and Cowshed) contain abundant colloform, cherty, and black quartz fill textures, with minor crustiform and massive quartz. The central veins (Amaranth, Trio, and Union) contain predominantly massive and crustiform textures, and these veins are also commonly coarser grained than outermost veins. Pyrite, sphalerite, galena, chalcopyrite, electrum, and acanthite occur in both outermost and central veins; base metal sulfide minerals typically increase in abundance in deeper samples. Antimony-, arsenic-, and selenium-bearing minerals are most abundant in the Favona and Moonlight veins, whereas base metal sulfide minerals are more abundant in the central veins at Correnso. Throughout the Waihi vein system, electrum is by far the most widespread, abundant, and significant gold-bearing mineral, but LA-ICP-MS analyses show that arsenian pyrite also contains some gold. Mineralogical and textural data are consistent with the central veins forming at a deeper structural level, or from hydrothermal fluids with different chemistry, or both.

  7. Photoluminescence of hollow gold-silver bimetallic nanoparticles

    Weon-Sik Chae; Hee-Ok Lee; Seung-Lim Oh


    Hollow gold nanoparticles including silver were prepared by the galvanic replacement reaction of silver nanoparticles by gold. The resulting hollow gold-silver bimetallic nanoparticles show notable blue-green emissions, which are studied using steady-state and time-resolved spectroscopy.

  8. Photoluminescence of hollow gold-silver bimetallic nanoparticles

    Weon-Sik Chae


    Full Text Available Hollow gold nanoparticles including silver were prepared by the galvanic replacement reaction of silver nanoparticles by gold. The resulting hollow gold-silver bimetallic nanoparticles show notable blue-green emissions, which are studied using steady-state and time-resolved spectroscopy.

  9. Gamma ray spectrometry for recognition of hydrothermal alteration zones related to a low sulfidation epithermal gold mineralization (eastern Pontides, NE Türkiye)

    Maden, Nafiz; Akaryalı, Enver


    This study presents an interpretation of radiospectrometric and magnetic data of Arzular mineralization site, which is one of the best examples for epithermal gold deposits located in the southern zone of the Eastern Pontides (NE Türkiye). Potassium is generally the most useful pathfinder element for gold mineralization zones because of its high level in altered rock surrounding the deposits. Where gold is hosted within quartz veins, typically the vein is low in the radioelements, but the hydrothermally altered host rocks will usually have a distinct radioelement signature useful for exploration. In this study, magnetic, susceptibility and radiospectrometric survey data radiometric signatures associated with the host rocks favorable for the mineralization, enhancing techniques such as the ratio maps as well as potassium (%K), equivalent thorium (eTh ppm) and equivalent uranium (eU ppm) maps were utilized. Our analysis showed that the gold mineralization associated with the alteration is significantly related to increase in potassium, due to adularia, a low T K-feldspar, and decreases in uranium and thorium due to the hydrothermal alteration and magmatic intrusion processes during the regional tectonic activities.

  10. Spatiotemporal reconstruction of Late Mesozoic silicic large igneous province and related epithermal mineralization in South China: Insights from the Zhilingtou volcanic-intrusive complex

    Wang, Guo-Guang; Ni, Pei; Zhao, Chao; Wang, Xiao-Lei; Li, Pengfei; Chen, Hui; Zhu, An-Dong; Li, Li


    Silicic large igneous provinces (SLIPs) generally reflect large-scale melting of lower crustal materials and represent significant metal reservoirs. The South China Block-Coastal Region (SCB-CR) SLIP hosts several large epithermal deposits. To better understand these deposits, we document the spatiotemporal framework of the host SLIP across the SCB-CR. Using zircon U-Pb dating and geochemical and isotopic analysis, we identify four stages of emplacement. Stage 1 felsophyre (circa 149 Ma) shows a chemical affinity to highly fractionated I-type granites. Stages 2 and 3 of low-Mg felsic volcanics (circa 128 to 111 Ma) and stage 4 felsite (circa 100 Ma) have higher ɛHf(t) and ɛNd(t) values than stage 1 felsophyre, suggesting a significant contribution of newly underplated juvenile crust to the magma sources. Stage 4 diabase (circa 101 Ma) was likely produced by melting of subduction˗metasomatized asthenospheric mantle. Together with reliable published data, we build a new spatiotemporal framework of volcanics and infer that the majority of the SCB-CR SLIP was related to the gradual northwestward subduction of the Izanagi plate beneath South China in a continental arc setting during circa 170 to 110 Ma, and minor contribution was from the eastward retreat of the subducting slab in a back-arc setting during circa 110 to 90 Ma. We conclude that the large-scale epithermal mineralization was generated by melting of the metal-rich, thin (30-40 km), newly underplated hydrous juvenile crust during the tectonic transition from arc to back-arc settings.

  11. Temporal and spatial distribution of alteration, mineralization and fluid inclusions in the transitional high-sulfidation epithermal-porphyry copper system at Red Mountain, Arizona

    Lecumberri-Sanchez, Pilar; Newton, M. Claiborne; Westman, Erik C.; Kamilli, Robert J.; Canby, Vertrees M.; Bodnar, Robert J.


    Red Mountain, Arizona, is a Laramide porphyry Cu system (PCD) that has experienced only a modest level of erosion compared to most other similar deposits in the southwestern United States. As a result, the upper portion of the magmatic–hydrothermal system, which represents the transition from shallower high-sulfidation epithermal mineralization to deeper porphyry Cu mineralization, is well preserved. Within the Red Mountain system, alteration, mineralization and fluid inclusion assemblages show a systematic distribution in both time and space. Early-potassic alteration (characterized by the minerals biotite and magnetite) is paragenetically earlier than late-potassic alteration (K-feldspar–anhydrite) and both are followed by later phyllic (sericite–pyrite) alteration. Advanced argillic alteration (pyrophyllite–alunite–other clay minerals) is thought to be coeval with or postdate phyllic alteration. Minerals characteristic of advanced argillic alteration are present in the near surface. Phyllic alteration extends to greater depths compared to advanced argillic alteration. Early-potassic and late-potassic alteration are only observed in the deepest part of the system. Considerable overlap of phyllic alteration with both early-potassic and late-potassic alteration zones is observed. The hypogene mineralization contains 0.4–1.2% Cu and is spatially and temporally related to the late-potassic alteration event. Molybdenum concentration is typically In the deepest part of the system, an early generation of low-to-moderate density and salinity liquid + vapor inclusions with opaque daughter minerals is followed in time by halite-bearing inclusions that also contain opaque daughter minerals indicating that an early intermediate-density magmatic fluid evolved to a high-density, high-salinity mineralizing fluid. The increase in density and salinity of fluids with time observed in the deeper parts of the system may be the result of immiscibility (“boiling”) of

  12. The Patricia Zn–Pb–Ag epithermal ore deposit: An uncommon type of mineralization in northeastern Chile

    Chinchilla, Darío; Ortega, L.; Piña, Rubén; Merinero, R.; Moncada, D.; Bodnar, Robert J.; Quesada, Cecilio; Valverde, Antonio; Lunar, Rosario


    The Patricia ore deposit represents an unusual example of economic Zn–Pb–Ag mineralization at the northernmost end of the Late Eocene–Oligocene metallogenic belt in Chile. It is hosted by volcano-sedimentary units, which are typically tuffaceous and andesitic breccias. The ore body consists of a set of subvertical E-W vein systems developed under a sinistral strike-slip regime that included transtensive domains with generalized extensional structures where the ores were deposited. The deposit...

  13. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    dos Santos, Margarida Moreira; Queiroz, Margarida João; Baptista, Pedro V.


    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 ± 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a β-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle-antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  14. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    Moreira dos Santos, Margarida, E-mail:; Queiroz, Margarida Joao; Baptista, Pedro V. [Universidade Nova de Lisboa, CIGMH, Departamento Ciencias da Vida, Faculdade de Ciencias e Tecnologia (Portugal)


    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 {+-} 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a {beta}-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle-antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  15. Intermediate sulfidation epithermal mineralization of No. 4 anomaly of Golojeh deposit (N. Zanjan based on mineralography, alteration and ore fluid geochemistry features

    Behzad Mehrab


    contents of galena, sphalerite and minor chalcopyrite and tennantite, low to moderate temperature and salinity of ore-bearing fluid, low depth of mineralization and Fe–bearing sphalerite features at the No. 4 anomaly of Golojeh deposit, are similar to those of intermediate sulfidation (IS epithermal base and precious metals vein–type deposit that probably might be related to Cu–Au porphyry system in depth.

  16. Mineral resources estimation based on block modeling

    Bargawa, Waterman Sulistyana; Amri, Nur Ali


    The estimation in this paper uses three kinds of block models of nearest neighbor polygon, inverse distance squared and ordinary kriging. The techniques are weighting scheme which is based on the principle that block content is a linear combination of the grade data or the sample around the block being estimated. The case study in Pongkor area, here is gold-silver resource modeling that allegedly shaped of quartz vein as a hydrothermal process of epithermal type. Resources modeling includes of data entry, statistical and variography analysis of topography and geological model, the block model construction, estimation parameter, presentation model and tabulation of mineral resources. Skewed distribution, here isolated by robust semivariogram. The mineral resources classification generated in this model based on an analysis of the kriging standard deviation and number of samples which are used in the estimation of each block. Research results are used to evaluate the performance of OK and IDS estimator. Based on the visual and statistical analysis, concluded that the model of OK gives the estimation closer to the data used for modeling.

  17. Multiple episodes of hydrothermal activity and epithermal mineralization in the southwestern Nevada volcanic field and their relations to magmatic activity, volcanism and regional extension

    Weiss, S.I.; Noble, D.C.; Jackson, M.C. [Univ. of Nevada, Reno, NV (United States)] [and others


    Volcanic rocks of middle Miocene age and underlying pre-Mesozoic sedimentary rocks host widely distributed zones of hydrothermal alteration and epithermal precious metal, fluorite and mercury deposits within and peripheral to major volcanic and intrusive centers of the southwestern Nevada volcanic field (SWNVF) in southern Nevada, near the southwestern margin of the Great Basin of the western United States. Radiometric ages indicate that episodes of hydrothermal activity mainly coincided with and closely followed major magmatic pulses during the development of the field and together spanned more than 4.5 m.y. Rocks of the SWNVF consist largely of rhyolitic ash-flow sheets and intercalated silicic lava domes, flows and near-vent pyroclastic deposits erupted between 15.2 and 10 Ma from vent areas in the vicinity of the Timber Mountain calderas, and between about 9.5 and 7 Ma from the outlying Black Mountain and Stonewall Mountain centers. Three magmatic stages can be recognized: the main magmatic stage, Mountain magmatic stage (11.7 to 10.0 Ma), and the late magmatic stage (9.4 to 7.5 Ma).

  18. Bimetallic gold-silver nanoplate array as a highly active SERS substrate for detection of streptavidin/biotin assemblies.

    Bi, Liyan; Dong, Jian; Xie, Wei; Lu, Wenbo; Tong, Wei; Tao, Lin; Qian, Weiping


    The silver-modified gold nanoplate arrays as bimetallic surface-enhanced Raman scattering (SERS) substrates were optimized for the surface-enhanced Raman detection of streptavidin/biotin monolayer assemblies. The bimetallic gold-silver nanoplate arrays were fabricated by coating silver nanoparticles uniformly on the gold nanoplate arrays. Depending on silver nanoparticle coating, the localized surface plasmon resonance (LSPR) peak of the bimetallic gold-silver nanoplate arrays blue-shifted and broadened significantly. The common probe molecule, Niel Blue A sulfate (NBA) was used for testing the SERS activity of the bimetallic gold-silver nanoplate arrays. The SERS intensity increased with the silver nanoparticle coating, due to a large number of hot spots and nanoparticle interfaces. The platforms were tested against a monolayer of streptavidin functionalized over the bimetallic gold-silver nanoplate arrays showing that good quality spectra could be acquired with a short acquisition time. The supramolecular interaction between streptavidin (strep) and biotin showed subsequent modification of Raman spectra that implied a change of the secondary structure of the host biomolecule. And the detection concentration for biotin by this method was as low as 1.0 nM. The enhanced SERS performance of such bimetallic gold-silver nanoplate arrays could spur further interest in the integration of highly sensitive biosensors for rapid, nondestructive, and quantitative bioanalysis, particularly in microfluidics.

  19. Gold-silver alloy nanoshells: a new candidate for nanotherapeutics and diagnostics

    Karmonik Christof


    Full Text Available Abstract We have developed novel gold-silver alloy nanoshells as magnetic resonance imaging (MRI dual T 1 (positive and T 2 (negative contrast agents as an alternative to typical gadolinium (Gd-based contrast agents. Specifically, we have doped iron oxide nanoparticles with Gd ions and sequestered the ions within the core by coating the nanoparticles with an alloy of gold and silver. Thus, these nanoparticles are very innovative and have the potential to overcome toxicities related to renal clearance of contrast agents such as nephrogenic systemic fibrosis. The morphology of the attained nanoparticles was characterized by XRD which demonstrated the successful incorporation of Gd(III ions into the structure of the magnetite, with no major alterations of the spinel structure, as well as the growth of the gold-silver alloy shells. This was supported by TEM, ICP-AES, and SEM/EDS data. The nanoshells showed a saturation magnetization of 38 emu/g because of the presence of Gd ions within the crystalline structure with r 1 and r 2 values of 0.0119 and 0.9229 mL mg-1 s-1, respectively (Au:Ag alloy = 1:1. T 1- and T 2-weighted images of the nanoshells showed that these agents can both increase the surrounding water proton signals in the T 1-weighted image and reduce the signal in T 2-weighted images. The as-synthesized nanoparticles exhibited strong absorption in the range of 600-800 nm, their optical properties being strongly dependent upon the thickness of the gold-silver alloy shell. Thus, these nanoshells have the potential to be utilized for tumor cell ablation because of their absorption as well as an imaging agent.

  20. Synthesis of bimetallic gold/silver nanoparticles via in situ seeding

    Gorbachevskiy, M. V.; Kopitsyn, D. S.; Tiunov, I. A.; Kotelev, M. S.; Vinokurov, V. A.; Novikov, A. A.


    A way of synthesizing bimetallic gold/silver nanoparticles with in situ seeding initiated by the addition of sodium borohydride is proposed. The obtained nanoparticles are studied by means of transmission electron microscopy (TEM). Changes in the optical density spectra of the nanoparticles during their coagulation are investigated. The technique allows the rapid acquisition of nontoxic SERS-active nanoparticles with maximum SERS enhancement factor about 105 in the near infrared range for Raman shifts typical for biological objects such as bacterial cells and spores.

  1. Mineral and geothermal resource potential of the Mount Hood Wilderness, Clackamas and Hood River Counties, Oregon. Summary report and map

    Keith, T.E.C.; Causey, J.D.


    The potential for near-surface mineral resources in the Mount Hood Wilderness is low. Geochemical data suggest two areas of weak epithermal mineralization in the Zigzag Mountain part of the wilderness: (1) the Lost Creek-Burnt Lake-Cast Creek-Short Creek area on the north side of Zigzag Mountain where vein-type lead-zinc-silver mineralization occurs; and (2) the Lady Creek-Laurel Hill area on the south side of Zigzag Mountain where the upper part of a quartz diorite pluton has associated propylitic alteration resulting in some porphyry-type copper, gold, silver, lead, and zinc mineralization. Geothermal-resource potential for low- to intermediate-temperature (less than 248/sup 0/F, 120/sup 0/C) hot-water systems in the wilderness is moderate to high. Part of the wilderness is classified as a Known Geothermal Resources Area (KGRA) and two parts have been included in geothermal lease areas. Rock and gravel sources are present within the wilderness; however, quantities of similar and more accessible deposits are available outside the wilderness. Deposits outside the wilderness are large enough to supply local demand in the foreseeable future.

  2. Laser-induced damage thresholds of gold, silver and their alloys in air and water

    Starinskiy, Sergey V.; Shukhov, Yuri G.; Bulgakov, Alexander V.


    The nanosecond-laser-induced damage thresholds of gold, silver and gold-silver alloys of various compositions in air and water have been measured for single-shot irradiation conditions. The experimental results are analyzed theoretically by solving the heat flow equation for the samples irradiated in air and in water taking into account vapor nucleation at the solid-water interface. The damage thresholds of Au-Ag alloys are systematically lower than those for pure metals, both in air and water that is explained by lower thermal conductivities of the alloys. The thresholds measured in air agree well with the calculated melting thresholds for all samples. The damage thresholds in water are found to be considerably higher, by a factor of ∼1.5, than the corresponding thresholds in air. This cannot be explained, in the framework of the used model, neither by the conductive heat transfer to water nor by the vapor pressure effect. Possible reasons for the high damage thresholds in water such as scattering of the incident laser light by the vapor-liquid interface and the critical opalescence in the superheated water are suggested. Optical pump-probe measurements have been performed to study the reflectance dynamics of the surface irradiated in air and water. Comparison of the transient reflectance signal with the calculated nucleation dynamics provides evidence that the both suggested scattering mechanisms are likely to occur during metal ablation in water.

  3. Aspartame-stabilized gold-silver bimetallic biocompatible nanostructures with plasmonic photothermal properties, antibacterial activity, and long-term stability.

    Fasciani, Chiara; Silvero, M Jazmin; Anghel, Maria Alexandra; Argüello, Gerardo A; Becerra, Maria Cecilia; Scaiano, Juan C


    Gold-silver core-shell nanoparticles stabilized with a common sweetener, aspartame (AuNP@Ag@Asm), combine the antimicrobial properties of silver with the photoinduced plasmon-mediated photothermal effects of gold. The particles were tested with several bacterial strains, while biocompatibility was verified with human dermal fibroblasts.

  4. Surface Plasmons and Surface Enhanced Raman Spectra of Aggregated and Alloyed Gold-Silver Nanoparticles

    Y. Fleger


    Full Text Available Effects of size, morphology, and composition of gold and silver nanoparticles on surface plasmon resonance (SPR and surface enhanced Raman spectroscopy (SERS are studied with the purpose of optimizing SERS substrates. Various gold and silver films made by evaporation and subsequent annealing give different morphologies and compositions of nanoparticles and thus different position of the SPR peak. SERS measurements of 4-mercaptobenzoic acid obtained from these films reveal that the proximity of the SPR peak to the exciting laser wavelength is not the only factor leading to the highest Raman enhancement. Silver nanoparticles evaporated on top of larger gold nanoparticles show higher SERS than gold-silver alloyed nanoparticles, in spite of the fact that the SPR peak of alloyed nanoparticles is narrower and closer to the excitation wavelength. The highest Raman enhancement was obtained for substrates with a two-peak particle size distribution for excitation wavelengths close to the SPR.

  5. Gold-silver-alloy nanoprobes for one-pot multiplex DNA detection

    Doria, G; Larguinho, M; Dias, J T; Baptista, P V [Centro de Investigacao em Genetica Molecular Humana (CIGMH), Departamento de Ciencias da Vida, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Pereira, E [Rede de Quimica e Tecnologia (REQUIMTE), Departamento de Quimica, Faculdade de Ciencias, Universidade do Porto, 4169-007 Porto (Portugal); Franco, R, E-mail: [Rede de Quimica e Tecnologia (REQUIMTE), Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)


    A specific colorimetric DNA detection method based on oligonucleotide functionalized gold-silver-alloy nanoparticles (AuAg-alloy-nanoprobes) is presented. The AuAg-alloy-nanoprobes were then used for the specific detection of a DNA sequence from TP53-a gene involved in cancer development. The AuAg-alloy-nanoprobes were then used in combination with Au-nanoprobes for a one-pot dual-colour detection strategy that allowed for the simultaneous differential detection of two distinct target sequences. This system poses an unprecedented opportunity to explore the combined use of metal nanoparticles with different composition towards the development of a multiplex one-pot colorimetric assay for DNA detection.

  6. Single-source precursors for alloyed gold-silver nanocrystals - a molecular metallurgy approach.

    Zopes, David; Hegemann, Corinna; Schläfer, Johannes; Tyrra, Wieland; Mathur, Sanjay


    Multiple silver(I)-aurates(I) have been prepared by salt metathesis reactions that act as efficient single-source precursors to colloidal gold silver alloys with the highest possible atom economy in the chemical synthesis of nanostructures. The CF3 group present on the Au cation acts as an in situ reducing agent and can be converted into CO ligands by simple hydrolysis. This ligand-mediated activation and subsequent decomposition of metal-organic precursors impose a molecular control over the nucleation process, producing homogeneously alloyed (Ag-Au) nanoparticles with an atomic Au:Ag ratio of 1:1. The concept also works for the Au-Cu system and acts as a pointer to replace Au (Ag) with less expensive (Cu) metals.

  7. Enhanced visualization of biodegradable polymeric vascular scaffolds by incorporation of gold, silver and magnetite nanoparticles.

    Luderer, Frank; Begerow, Ivonne; Schmidt, Wolfram; Martin, Heiner; Grabow, Niels; Bünger, Carsten M; Schareck, Wolfgang; Schmitz, Klaus-Peter; Sternberg, Katrin


    Due to improved tissue regeneration and the enabling of post-operative minimally invasive interventions in the same vessel segment, biodegradable polymeric scaffolds represent a competitive approach to permanent metallic stents in vascular applications. Despite these advantages some challenges, such as the improvement of the scaffold mechanics and enhancement of scaffold visibility during the implantation procedure, are persisting. Therefore, the scope of our studies was to investigate the potential of gold, silver and magnetite nanoparticles incorporated in a polymeric blend of poly(L-lactide)/poly(4-hydroxybutyrate) for image enhancement in X-ray, magnetic resonance or near-infrared imaging. Their impact on mechanical properties of such modified scaffold materials was also evaluated.

  8. Oxygen Isotope Studies of Epithermal Systems:A Review

    熊永良; 翟裕生


    Numerous stable isotope studies of whole rocks and mineral separates in epithermal systems indi-cate that even though meteoric waters are dominant components in epithermal systems ,fluids of other origins,such as sedimentary or meta-sedimentary fluids,magmatic waters and even evolved meteoric waters ,may also play a role in the formation of epithermal ore deposits.Usually the more depleted the wall rocks,the larger the size of ore deposits ,and the least depletion degrees in whole rocks for economic mineralization are by about 3.5‰.The depletion in δ18O in wall rocks,however,may be complicated by the superimposition of low temperature-hydration over high-temperature altera-tion or vice versa,the existence of primary low-18O and high-18O magmas ,and alteration by vol-canic gases.The depletion in δ18O in wall rocks is controlled by the composition and nature of flu-ids,the temperature of fluids,the elevation of rocks at the time of alteration ,lithology,boiling effects of fluids ,and alteration style,as well as by water/rock ratios.In addition ,the fluids re-sponsible for epithermal deposits have experienced positive δ18O shifts .It seems that when the above complications and controlling factors are well defined,oxygen isotope studies would be a promising and powerful exploration tool.

  9. Los fluidos hidrotermales formadores de la mineralización epitermal el Dorado-Monserrat, Macizo del Deseado Hydrothermal fluids ofthe El Dorado-Monserrat epithermal mineralization, Macizo del Deseado

    Leandro E. Echavarría


    Full Text Available El Dorado-Monserrat es un depósito epitermal de baja sulfuración ubicado en el Macizo del Deseado. La mineralización vetiforme de Au y Ag está genéticamente relacionada a la Formación Chon Aike del Jurásico medio a superior y emplazada en rocas volcánicas del Jurásico medio correspondientes a la Formación Bajo Pobre. La mineralización se presenta en vetas constituidas principalmente por cuarzo, acompañado por adularia, pirita, hematita, magnetita y baritina. Los metales preciosos se encuentran en electrum, el que presenta una fuerte zonación de Au y Ag. A partir de la temperatura de homogeneización de inclusiones fluidas, la precipitación mineral es estimada entre 280° C y 180° C a partir de fluidos de baja salinidad de origen principalmente meteórico. El mecanismo de transporte del Au y Agha sido en solución como complejos bisulfurados (HS2 . Evidencias mineralógicas y texturales, que incluyen generación temprana de calcita en hojas, posteriormente reemplazada por cuarzo, y la precipitación de adularia rómbica, sugieren que la precipitación mineral, incluida la del Au y Ag, es debida a ebullición. Los estudios paragenéticos y termoquímicos han permitido la determinación de las condiciones de los fluidos hidrotermales que poseían una fO2 entre -33,5 y -34 y un pH de 5,2 a 6.El Dorado-Monserrat is a low-sulphide epithermal deposit located in the Macizo del Deseado, Santa Cruz province, Argentina. Au and Ag vein mineralisation is genetically linked to the Chon Aike Formation of Late to Middle Jurassic age and is hosted by volcanic rocks of the Middle Jurassic Bajo Pobre Formation. The mineralization is present in veins carrying quartz, adularia, pyrite, hematite, magnetite and barite. Precious metals are contained in electrum, which presents a strong Au to Ag zonation. From fluid-inclusion homogenisation temperatures, mineral precipitation is estimated at between 280° C and 180° C from low-salinity fluids mainly of

  10. Gold/silver core-shell 20 nm nanoparticles extracted from citrate solution examined by XPS

    Engelhard, Mark H.; Smith, Jordan N.; Baer, Donald R.


    Silver nanoparticles of many types are widely used in consumer and medical products. The surface chemistry of particles and the coatings that form during synthesis or use in many types of media can significantly impact the behaviors of particles including dissolution, transformation and biological or environmental impact. Consequently it is useful to be able to extract information about the thickness of surface coatings and other attributes of nanoparticles produced in a variety of ways. It has been demonstrated that X-ray Photoelectron Spectroscopy (XPS) can be reliably used to determine the thickness of organic and other nanoparticles coatings and shells. However, care is required to produce reliable and consistent information. Here we report the XPS spectra from gold/silver core-shell nanoparticles of nominal size 20 nm removed from a citrate saturated solution after one and two washing cycles. The Simulation of Electron Spectra for Surface Analysis (SESSA) program had been used to model peak amplitudes to obtain information on citrate coatings that remain after washing and demonstrate the presence of the gold core. This data is provided so that others can compare use of SESSA or other modeling approaches to quantify the nature of coatings to those already published and to explore the impacts particle non-uniformities on XPS signals from core-shell nanoparticles.

  11. Anomalous concentrations of gold, silver, and other metals in the Mill Canyon area, Cortez quadrangle, Eureka and Lander Counties, Nevada

    Elliott, James E.; Wells, John David


    The Mill Canyon area is in the eastern part of the Cortez window of the Roberts Mountains thrust belt in the Cortez quadrangle, north-central Nevada. Gold and silver ores have been mined from fissure veins in Jurassic quartz monzonite and in the bordering Wenban Limestone of Devonian age. Geochemical data show anomalies of gold, silver, lead, zinc, copper, arsenic, antimony, mercury, and tellurium. Geologic and geochemical studies indicate that a formation favorable for gold deposition, the Roberts Mountains Limestone of Silurian age, may be found at depth near the mouth of Mill Canyon.

  12. Additional mineral resources assessment of the Battle Creek, Bruneau River, Deep Creek-Owyhee River, Jarbidge River, Juniper Creek, Little Owyhee River, North Fork Owyhee River, Owyhee River Canyon, South Fork Owyhee River, Upper Deep Creek, and Yatahoney Creek Wilderness Study Areas, Owyhee County, Idaho

    Diggles, Michael F.; Berger, Byron R.; Vander Meulen, Dean B.; Minor, Scott A.; Ach, Jay A.; Sawlan, Michael G.


    From 1984 to 1986, studies were conducted to assess the potential for undiscovered mineral resources in wilderness study areas on the Owyhee Plateau. The results of these studies have been published in a series of U.S. Geological Survey Bulletins. Since that time, low-grade, high-tonnage epithermal hot-spring gold-silver deposits have been recognized in the region north of the wilderness study areas. The recognition that this mineral-deposit model is applicable in the region, coupled with new data that has become available to the U.S. Geological Survey, reinterpretation of existing geochemical data, and known-deposit data suggest that similar deposits may be present elsewhere on the Owyhee Plateau. This report is an additional assessment of the Battle Creek, Bruneau River, Deep Creek-Owyhee River, Jarbidge River, Juniper Creek, Little Owyhee River, North Fork Owyhee River, Owyhee River Canyon, South Fork Owyhee River (ID-016-053), Upper Deep Creek, and Yatahoney Creek Wilderness Study Areas in Idaho Wilderness Study Areas in Idaho in light of those new data.

  13. Mineral Resources of the Antelope Wilderness Study Area, Nye County, Nevada

    Hardyman, Richard F.; Poole, Forrest G.; Kleinhampl, Frank J.; Turner, Robert L.; Plouff, Donald; Duval, Joe S.; Johnson, Fredrick L.; Benjamin, David A.


    margin of the study area have moderate mineral resource potential for gold and silver in sediment-hosted, disseminated, epithermal (low-temperature) gold-silver deposits (fig. 1). These rocks consist of folded and thrust-faulted, fine-grained clastic sediments and limestone and dolomite that locally have been brecciated and hydrothermally altered. The alteration (locally, strong silicification) and geochemical associations of these rocks indicate a favorable environment for such deposits. Exploration for disseminated gold deposits in the same geologic environment is currently being conducted just south of the study area. The remainder of the study area has low resource potential for epithermal gold and silver vein deposits in the Tertiary volcanic rocks. The Cenozoic sedimentary basins adjacent to the fault-bounded mountain block have moderate potential for petroleum resources; the study area itself has low potential for petroleum resources.

  14. Optimizing the Drude-Lorentz model for material permittivity: Method, program, and examples for gold, silver, and copper

    Sehmi, H. S.; Langbein, W.; Muljarov, E. A.


    Approximating the frequency dispersion of the permittivity of materials with simple analytical functions is of fundamental importance for understanding and modeling the optical response of materials and resulting structures. In the generalized Drude-Lorentz model, the permittivity is described in the complex frequency plane by a number of simple poles having complex weights, which is a physically relevant and mathematically simple approach: By construction, it respects causality, represents physical resonances of the material, and can be implemented easily in numerical simulations. We report here an efficient method of optimizing the fit of measured data with the Drude-Lorentz model having an arbitrary number of poles. We show examples of such optimizations for gold, silver, and copper, for different frequency ranges and up to four pairs of Lorentz poles taken into account. We also provide a program implementing the method for general use.

  15. Gold silver alloy nanoparticles (GSAN): an imaging probe for breast cancer screening with dual-energy mammography or computed tomography

    Naha, Pratap C.; Lau, Kristen C.; Hsu, Jessica C.; Hajfathalian, Maryam; Mian, Shaameen; Chhour, Peter; Uppuluri, Lahari; McDonald, Elizabeth S.; Maidment, Andrew D. A.; Cormode, David P.


    Earlier detection of breast cancer reduces mortality from this disease. As a result, the development of better screening techniques is a topic of intense interest. Contrast-enhanced dual-energy mammography (DEM) is a novel technique that has improved sensitivity for cancer detection. However, the development of contrast agents for this technique is in its infancy. We herein report gold-silver alloy nanoparticles (GSAN) that have potent DEM contrast properties and improved biocompatibility. GSAN formulations containing a range of gold : silver ratios and capped with m-PEG were synthesized and characterized using various analytical methods. DEM and computed tomography (CT) phantom imaging showed that GSAN produced robust contrast that was comparable to silver alone. Cell viability, reactive oxygen species generation and DNA damage results revealed that the formulations with 30% or higher gold content are cytocompatible to Hep G2 and J774A.1 cells. In vivo imaging was performed in mice with and without breast tumors. The results showed that GSAN produce strong DEM and CT contrast and accumulated in tumors. Furthermore, both in vivo imaging and ex vivo analysis indicated the excretion of GSAN via both urine and feces. In summary, GSAN produce strong DEM and CT contrast, and has potential for both blood pool imaging and for breast cancer screening.Earlier detection of breast cancer reduces mortality from this disease. As a result, the development of better screening techniques is a topic of intense interest. Contrast-enhanced dual-energy mammography (DEM) is a novel technique that has improved sensitivity for cancer detection. However, the development of contrast agents for this technique is in its infancy. We herein report gold-silver alloy nanoparticles (GSAN) that have potent DEM contrast properties and improved biocompatibility. GSAN formulations containing a range of gold : silver ratios and capped with m-PEG were synthesized and characterized using various

  16. Assessment of Undiscovered Deposits of Gold, Silver, Copper, Lead, and Zinc in the United States: A Portable Document (PDF) Recompilation of USGS Open-File Report 96-96 and Circular 1178

    U.S. Geological Survey National Mineral Resource Assessment Team Recompiled by Schruben, Paul G.


    This publication contains the results of a national mineral resource assessment study. The study (1) identifies regional tracts of ground believed to contain most of the nation's undiscovered resources of gold, silver, copper, lead, and zinc in conventional types of deposits; and (2) includes probabilistic estimates of the amounts of these undiscovered resources in most of the tracts. It also contains a table of the significant known deposits in the tracts, and includes descriptions of the mineral deposit models used for the assessment. The assessment was previously released in two major publications. The conterminous United States assessment was published in 1996 as USGS Open-File Report 96-96. Subsequently, the Alaska assessment was combined with the conterminous assessment in 1998 and released as USGS Circular 1178. This new recompilation was undertaken for several reasons. First, the graphical browser software used in Circular 1178 was ONLY compatible with the Microsoft Windows operating system. It was incompatible with the Macintosh operating system, Linux, and other types of Unix computers. Second, the browser on Circular 1178 is much less intuitive to operate, requiring most users to follow a tutorial to understand how to navigate the information on the CD. Third, this release corrects several errors and numbering inconsistencies in Circular 1178.

  17. Re Os isotopes applied to the epithermal gold deposits near Bucaramanga, northeastern Colombia

    Mathur, R.; Ruiz, J.; Herb, P.; Hahn, L.; Burgath, K.-P.


    The epithermal gold mineralization near Bucaramanga, Colombia, is spatially associated with a dacitic porphyry of Upper Cretaceous to Early Tertiary age. Two mining districts in the vicinity of Bucaramanga, the California and the Vetas, host different styles of mineralization that could be interpreted as high- and low-sulfidation style mineralization, respectively. Re-Os isotope systematics were used on sulfide-gold-rich gravity concentrates in an attempt to determine both the ages of the epithermal deposits and the possible genetic relationships between the porphyry and the epithermal mineralization. The concentration of Os for sulfide samples taken from both systems is relatively uniform, ranging from 19 to 35 ppt (parts per trillion), whereas the Re concentration varies significantly, with the California system averaging 10 ppb (parts per billion) and the Vetas system averaging 140 ppb. The samples from the high-sulfidation California deposit form an isochron with an age of 57±10 Ma (MSWD=0.8), which overlaps with the age of the dacitic volcanism. The initial 187Os/ 188Os of the isochron is 1.20±0.13 and indicates a predominately crustal source for the Os and, by inference, gold. The samples from the Vetas low-sulfidation system have very high Re/Os ratios and do not lie on the isochron. These data reveal a difference between two epithermal systems that border one intrusion. Sulfide samples from the high-sulfidation system are isotopically homogenous with respect to Re-Os (form an isochron) and probably represent mineralization linked closely with the high temperature volatiles/fluids from the magma. In contrast, the sulfides from the Vetas system are in disequilibrium with respect to Re-Os and may illustrate mineralization that is not directly related to similar magmatic fluids.

  18. Database of significant deposits of gold, silver, copper, lead, and zinc in the United States

    Long, Keith R.; DeYoung, Jr., John H.; Ludington, Stephen


    It has long been recognized that the largest mineral deposits contain most of the known mineral endowment (Singer and DeYoung, 1980). Sometimes called giant or world-class deposits, these largest deposits account for a very large share of historic and current mineral production and resources in industrial society (Singer, 1995). For example, Singer (1995) shows that the largest 10 percent of the world’s gold deposits contain 86 percent of the gold discovered to date. Many mineral resource issues and investigations are more easily addressed if limited to the relatively small number of deposits that contain most of the known mineral resources. An estimate of known resources using just these deposits would normally be sufficient, because considering smaller deposits would not add significantly to the total estimate. Land-use planning should treat mainly with these deposits due to their relative scarcity, the large share of known resources they contain, and the fact that economies of scale allow minerals to be produced much more cheaply from larger deposits. Investigation of environmental and other hazards that result from mining operations can be limited to these largest deposits because they account for most of past and current production.

  19. Construction of the WSU Epithermal Neutron Filter

    Venhuizen, James Robert; Nigg, David Waler; Tripard, G.


    Moderating material has been installed in the original thermal-neutron filter region of the Washington State University (WSU) TRIGA™ type reactor to produce an epithermal-neutron beam. Attention has been focused upon the development of a convenient, local, epithermal-neutron beam facility at WSU for collaborative Idaho National Engineering and Environmental Laboratory (INEEL)/WSU boron neutron capture therapy (BNCT) preclinical research and boronated pharmaceutical screening in cell and animal models. The design of the new facility was performed in a collaborative effort1,2 of WSU and INEEL scientists. This paper summarizes the physical assembly of this filter.

  20. Epithermal neutron beam interference with cardiac pacemakers

    Koivunoro, H., E-mail: [Department of Physics, P.O.B. 64, FI-00014 University of Helsinki (Finland)] [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland)] [Boneca Corporation, Finland, Filnland (Finland); Seren, T. [VTT Technical Research Centre of Finland (Finland); Hyvoenen, H. [Boneca Corporation, Finland, Filnland (Finland); Kotiluoto, P. [VTT Technical Research Centre of Finland (Finland); Iivonen, P. [St. Jude Medical (Finland); Auterinen, I. [VTT Technical Research Centre of Finland (Finland); Seppaelae, T.; Kankaanranta, L. [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland); Pakarinen, S. [Department of Cardiology, Helsinki University Central Hospital (Finland); Tenhunen, M. [Department of Oncology, Helsinki University Central Hospital, P.O.B. 180, FIN-00029 HUS (Finland); Savolainen, S. [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital (Finland)


    In this paper, a phantom study was performed to evaluate the effect of an epithermal neutron beam irradiation on the cardiac pacemaker function. Severe malfunction occurred in the pacemakers after substantially lower dose from epithermal neutron irradiation than reported in the fast neutron or photon beams at the same dose rate level. In addition the pacemakers got activated, resulting in nuclides with half-lives from 25 min to 115 d. We suggest that BNCT should be administrated only after removal of the pacemaker from the vicinity of the tumor.

  1. Mineral resource potential map of the Blanco Mountain and Black Canyon roadless areas, Inyo and Mono counties, California

    Diggles, Michael F.; Blakely, Richard J.; Rains, Richard L.; Schmauch, Steven W.


    On the basis of geologic, geochemical, and geophysical investigations and a survey of mines and prospects, the mineral resource potential for gold, silver, lead, zinc, tungsten, and barite of the Blanco Mountain and Black Canyon Roadless Areas is judged to be low to moderate, except for one local area that has high potential for gold and tungsten resources.

  2. In situ growth of hollow gold-silver nanoshells within porous silica offers tunable plasmonic extinctions and enhanced colloidal stability.

    Li, Chien-Hung; Jamison, Andrew C; Rittikulsittichai, Supparesk; Lee, Tai-Chou; Lee, T Randall


    Porous silica-coated hollow gold-silver nanoshells were successfully synthesized utilizing a procedure where the porous silica shell was produced prior to the transformation of the metallic core, providing enhanced control over the structure/composition of the bimetallic hollow core. By varying the reaction time and the precise amount of gold salt solution added to a porous silica-coated silver-core template solution, composite nanoparticles were tailored to reveal a readily tunable surface plasmon resonance that could be centered across the visible and near-IR spectral regions (∼445-800 nm). Characterization by X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy revealed that the synthetic methodology afforded particles having uniform composition, size, and shape. The optical properties were evaluated by absorption/extinction spectroscopy. The stability of colloidal solutions of our composite nanoparticles as a function of pH was also investigated, revealing that the nanoshells remain intact over a wide range of conditions (i.e., pH 2-10). The facile tunability, enhanced stability, and relatively small diameter of these composite particles (∼110 nm) makes them promising candidates for use in tumor ablation or as photothermal drug-delivery agents.

  3. Femtosecond Laser-Induced Formation of Gold-Rich Nanoalloys from the Aqueous Mixture of Gold-Silver Ions

    Yuliati Herbani


    Full Text Available The synthesis of gold-silver (AuAg nanoalloys of various compositions has been performed by direct irradiation of highly intense femtosecond laser pulse in the presence of polyvinylpyrrolidone (PVP. The mixture of Au and Ag ions of low concentration was simply introduced into a glass vial and subjected to femtosecond laser pulses for several minutes. The AuAg nanoalloys of 2-3 nm with reasonably narrow size distribution were formed, and the position of the surface plasmon resonance (SPR increased monotonically with an increase in the gold molar fraction in the ion solutions. The high resolution transmission electron microscope (HRTEM images exhibited the absence of core-shell structures, and the energy dispersive X-ray spectroscopy (EDX analysis confirmed that the particles were Au-rich alloys even for the samples with large fraction of Ag+ ions fed in the solution mixture. The formation mechanism of the alloy nanoparticles in the high intensity optical field was also discussed.

  4. Experimental (SERS) and theoretical (DFT) studies on the adsorption behaviors of L-cysteine on gold/silver nanoparticles

    Jing, Cuiyu; Fang, Yan


    It is important to apply the surface-enhanced Raman scattering (SERS) spectra and density functional theory (DFT) to study the interfacial properties of nanoparticles and the adsorption behavior of molecules on the substrates. In the paper, the adsorption behaviors of L-cysteine molecules on gold/silver nanoparticles were studied. It was demonstrated that in gold colloidal solution, L-cysteine molecules were adsorbed in P H conformation and interacted with the gold surface simultaneously through sulfur, NH3+ and COO - groups. However, in silver colloidal solution activated by coadsorption of chloride anions, we could see that for most of the L-cysteine molecules, the collision of two L-cysteine molecules may lead to the formation of one L-cystine molecule by the S-S bond, and a few of L-cysteine molecules existed as the P H and P N conformations, and the molecules attached to the silver surface via the carboxylate and amino groups. The calculated Raman frequencies using DFT-B3LYP/6-31++G(d,p) of L-cysteine molecule were in good agreement with experimental values, which demonstrated that the DFT method can be taken as a very useful tool to assign the Raman band.

  5. Textural Evidence of Episodic Introduction of Metallic Nanoparticles into Bonanza Epithermal Ores

    James A. Saunders


    Full Text Available Tertiary low sulfidation (LS epithermal deposits in the western USA often show evidence of the former presence of nanoparticle-sized precious-metal and silica phases in the highest grade (bonanza ores. Here, nanoparticles are defined to have a size less than ~10−7 m. The ore-mineral textures that formed from aggregation of nanoparticles (or colloids observed to date in these ores include electrum and naumannite (Ag2Se. Here it is proposed that chalcopyrite also forms nanoparticles in these ores, but sulfide nanoparticles apparently have significantly different physical (surface properties than the precious-metal phases, and thus exhibit different mineral textures (e.g., no textural evidence of previous chalcopyrite nanoparticles. Textures described here show that nanoparticles of precious-metal phases and silica were episodically and often repeatedly deposited to form the banded bonanza veins typical of many western USA epithermal deposits. Chalcopyrite is the most abundant metal-sulfide mineral in these bonanza ores, and it was also deposited episodically as well, and it appears to replace earlier formed naumannite dendrites. However, this apparent “replacement” texture may just be the result of naumannite dendrite limbs trapping chalcopyrite nanoparticles that later recrystallized to the apparent replacement texture. The episodic and repetitive nature of the metal-depositing events may record periodic “degassing” of magma chambers at depth, where metals are repeatedly delivered to the shallow epithermal environment by “vapor-phase” metal (loid transport.

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


    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.

  7. Characterisation of the TAPIRO BNCT epithermal facility.

    Burn, K W; Colli, V; Curzio, G; d'Errico, F; Gambarini, G; Rosi, G; Scolari, L


    A collimated epithermal beam for boron neutron capture therapy (BNCT) research has been designed and built at the TAPIRO fast research reactor. A complete experimental characterisation of the radiation field in the irradiation chamber has been performed, to verify agreement with IAEA requirements. Slow neutron fluxes have been measured by means of an activation technique and with thermoluminescent detectors (TLDs). The fast neutron dose has been determined with gel dosemeters, while the fast neutron spectrum has been acquired by means of a neutron spectrometer based on superheated drop detectors. The gamma-dose has been measured with gel dosemeters and TLDs. For an independent verification of the experimental results, fluxes, doses and neutron spectra have been calculated with Monte Carlo simulations using the codes MCNP4B and MCNPX_2.1.5 with the direct statistical approach (DSA). The results obtained confirm that the epithermal beams achievable at TAPIRO are of suitable quality for BNCT purposes.

  8. Minerales de mena del depósito epitermal de baja sulfuración Don Sixto, Mendoza Ore minerals from Don Sixto, a low sulfidation epithermal deposit from Mendoza

    Ana Cecilia Mugas Lobos


    Full Text Available El proyecto minero Don Sixto es un depósito epitermal de baja sulfuración de Au-Ag, ubicado en el bloque de San Rafael, en el SE de la provincia de Mendoza. En este depósito, cuyo recurso aurífero es próximo a las 900.000 onzas, se ha identificado una asociación de minerales de metales preciosos que incluye: uytenbogaardtita, stromeyerita, naumannita, acantita, polibasita, stützita y cervelleita. Estos minerales son escasos y se encuentran frecuentemente asociados a oro y plata de variable fineza, diseminados en vetas de cuarzo hidrotermal y en unidades volcánicas-piroclásticas de los Grupos Choiyoi y El Portillo. En este depósito se encuentra abundante pirita, con cantidades menores de arsenopirita, calcopirita, esfalerita, magnetita, hematita y, en forma subordinada, pirrotina, galena, marcasita, bornita y boulangerita, junto con calcosina, digenita y covellina. La presencia de uytenbogaardtita, stützita, cervelleita y polibasita constituye la primera mención de estos minerales para la provincia de Mendoza.The Don Sixto mining project is a low sulfidation Au-Ag deposit, with a gold resource close to 900,000 ounces, located in the San Rafael Massif, in the SE of Mendoza province. Recently, it was found a precious-metal mineral association including uy-tenbogaardtite, stromeyerite, naumannite, acanthite, polybasite, stützite and cervelleite. These minerals are scarce and are commonly related to gold and silver of variable fineness, disseminated in hydrothermal quartz veins and volcanic-pyroclastic rock units from the Choiyoi and El Portillo Group. The most common mineral is pyrite associated with subordinated arsenopyrite, chalcopyrite, sphalerite, magnetite and hematite; lesser amounts of pyrrhotite, galena, marcasite, bornite, boulangerite, chalcocite, digenite and covellite were also recognized. This is the first mention in Mendoza province for uytenbogaardtite, stützite, cervelleite and polybasite.

  9. Detection of adenosine triphosphate through polymerization-induced aggregation of actin-conjugated gold/silver nanorods

    Liao, Yu-Ju; Shiang, Yen-Chun; Chen, Li-Yi; Hsu, Chia-Lun; Huang, Chih-Ching; Chang, Huan-Tsung


    We have developed a simple and selective nanosensor for the optical detection of adenosine triphosphate (ATP) using globular actin-conjugated gold/silver nanorods (G-actin-Au/Ag NRs). By simply mixing G-actin and Au/Ag NRs (length ˜56 nm and diameter ˜12 nm), G-actin-Au/Ag NRs were prepared which were stable in physiological solutions (25 mM Tris-HCl, 150 mM NaCl, 5.0 mM KCl, 3.0 mM MgCl2 and 1.0 mM CaCl2; pH 7.4). Introduction of ATP into the G-actin-Au/Ag NR solutions in the presence of excess G-actin induced the formation of filamentous actin-conjugated Au/Ag NR aggregates through ATP-induced polymerization of G-actin. When compared to G-actin-modified spherical Au nanoparticles having a size of 13 nm or 56 nm, G-actin-Au/Ag NRs provided better sensitivity for ATP, mainly because the longitudinal surface plasmon absorbance of the Au/Ag NR has a more sensitive response to aggregation. This G-actin-Au/Ag NR probe provided high sensitivity (limit of detection 25 nM) for ATP with remarkable selectivity (>10-fold) over other adenine nucleotides (adenosine, adenosine monophosphate and adenosine diphosphate) and nucleoside triphosphates (guanosine triphosphate, cytidine triphosphate and uridine triphosphate). It also allowed the determination of ATP concentrations in plasma samples without conducting tedious sample pretreatments; the only necessary step was simple dilution. Our experimental results are in good agreement with those obtained from a commercial luciferin-luciferase bioluminescence assay. Our simple, sensitive and selective approach appears to have a practical potential for the clinical diagnosis of diseases (e.g. cystic fibrosis) associated with changes in ATP concentrations.

  10. Lithographically patterned electrodeposition of gold, silver, and nickel nanoring arrays with widely tunable near-infrared plasmonic resonances.

    Halpern, Aaron R; Corn, Robert M


    A novel low-cost nanoring array fabrication method that combines the process of lithographically patterned nanoscale electrodeposition (LPNE) with colloidal lithography is described. Nanoring array fabrication was accomplished in three steps: (i) a thin (70 nm) sacrificial nickel or silver film was first vapor-deposited onto a plasma-etched packed colloidal monolayer; (ii) the polymer colloids were removed from the surface, a thin film of positive photoresist was applied, and a backside exposure of the photoresist was used to create a nanohole electrode array; (iii) this array of nanoscale cylindrical electrodes was then used for the electrodeposition of gold, silver, or nickel nanorings. Removal of the photoresist and sacrificial metal film yielded a nanoring array in which all of the nanoring dimensions were set independently: the inter-ring spacing was fixed by the colloidal radius, the radius of the nanorings was controlled by the plasma etching process, and the width of the nanorings was controlled by the electrodeposition process. A combination of scanning electron microscopy (SEM) measurements and Fourier transform near-infrared (FT-NIR) absorption spectroscopy were used to characterize the nanoring arrays. Nanoring arrays with radii from 200 to 400 nm exhibited a single strong NIR plasmonic resonance with an absorption maximum wavelength that varied linearly from 1.25 to 3.33 μm as predicted by a simple standing wave model linear antenna theory. This simple yet versatile nanoring array fabrication method was also used to electrodeposit concentric double gold nanoring arrays that exhibited multiple NIR plasmonic resonances.

  11. Plasmonically Enhanced Photocatalytic Hydrogen Production from Water: The Critical Role of Tunable Surface Plasmon Resonance from Gold-Silver Nanoshells.

    Li, Chien-Hung; Li, Min-Chih; Liu, Si-Ping; Jamison, Andrew C; Lee, Dahye; Lee, T Randall; Lee, Tai-Chou


    Gold-silver nanoshells (GS-NSs) having a tunable surface plasmon resonance (SPR) were employed to facilitate charge separation of photoexcited carriers in the photocalytic production of hydrogen from water. Zinc indium sulfide (ZnIn2S4; ZIS), a visible-light-active photocatalyst, where the band gap varies with the [Zn]/[In] ratio, was used as a model ZIS system (E(g) = 2.25 eV) to investigate the mechanisms of plasmonic enhancement associated with the nanoshells. Three types of GS-NS cores with intense absorptions centered roughly at 500, 700, and 900 nm were used as seeds for preparing GS-NS@ZIS core-shell structures via a microwave-assisted hydrothermal reaction, yielding core-shell particles with composite diameters of ∼200 nm. Notably, an interlayer of dielectric silica (SiO2) between the GS-NSs and the ZIS photocatalyst provided another parameter to enhance the production of hydrogen and to distinguish the charge-transfer mechanisms. In particular, the direct transfer of hot electrons from the GS-NSs to the ZIS photocatalyst was blocked by this layer. Of the 10 particle samples examined in this study, the greatest hydrogen gas evolution rate was observed for GS-NSs having a SiO2 interlayer thickness of ∼17 nm and an SPR absorption centered at ∼700 nm, yielding a rate 2.6 times higher than that of the ZIS without GS-NSs. The apparent quantum efficiencies for these core-shell particles were recorded and compared to the absorption spectra. Analyses of the charge-transfer mechanisms were evaluated and are discussed based on the experimental findings.

  12. Gold-silver@TiO2 nanocomposite-modified plasmonic photoanodes for higher efficiency dye-sensitized solar cells.

    Lim, Su Pei; Lim, Yee Seng; Pandikumar, Alagarsamy; Lim, Hong Ngee; Ng, Yun Hau; Ramaraj, Ramasamy; Bien, Daniel Chia Sheng; Abou-Zied, Osama K; Huang, Nay Ming


    In the present investigation, gold-silver@titania (Au-Ag@TiO2) plasmonic nanocomposite materials with different Au and Ag compositions were prepared using a simple one-step chemical reduction method and used as photoanodes in high-efficiency dye-sensitized solar cells (DSSCs). The Au-Ag incorporated TiO2 photoanode demonstrated an enhanced solar-to-electrical energy conversion efficiency of 7.33%, which is ∼230% higher than the unmodified TiO2 photoanode (2.22%) under full sunlight illumination (100 mW cm(-2), AM 1.5G). This superior solar energy conversion efficiency was mainly due to the synergistic effect between the Au and Ag, and their surface plasmon resonance effect, which improved the optical absorption and interfacial charge transfer by minimizing the charge recombination process. The influence of the Au-Ag composition on the overall energy conversion efficiency was also explored, and the optimized composition with TiO2 was found to be Au75-Ag25. This was reflected in the femtosecond transient absorption dynamics in which the electron-phonon interaction in the Au nanoparticles was measured to be 6.14 ps in TiO2/Au75:Ag25, compared to 2.38 ps for free Au and 4.02 ps for TiO2/Au100:Ag0. The slower dynamics indicates a more efficient electron-hole separation in TiO2/Au75:Ag25 that is attributed to the formation of a Schottky barrier at the interface between TiO2 and the noble metal(s) that acts as an electron sink. The significant boost in the solar energy conversion efficiency with the Au-Ag@TiO2 plasmonic nanocomposite showed its potential as a photoanode for high-efficiency DSSCs.

  13. A novel and greener approach for shape controlled synthesis of gold and gold-silver core shell nanostructure and their application in optical coatings.

    Sinha, Tanur; Ahmaruzzaman, M


    Green and facile synthetic methods have gained marvellous fame for the production of polyhedral, anisotropic and spherical gold, and gold-silver bimetallic nanostructures. The useful pivotal characteristics of a green procedure are the usage of environment benign solvent medium, reducing and stabilising agents, and shorter reaction time. We describe here a novel, and greener method for the production of gold and gold-silver core shell nanostructures using aqueous fish scales extract of the Labeo rohita. The effect of various reaction parameters, such as temperature and concentration for the synthesis of the nanostructures were studied. Results indicated that triangular and decahedron gold nanostructures were formed at a lower temperature (40°C) and concentration (10%). While, icosahedral and spherical gold nanostructures were produced at a comparatively higher temperature (100°C) and concentration (40%). The study also revealed that the core-shell bimetallic nanostructures with different morphologies (spherical and oval-shape) were formed at different ratios of chloroaurate and silver nitrate solution. Thus, the present study indicated a simple shape controlled synthesis of gold and gold silver core-shell nanostructures. The synthesised gold nanotriangles were coated over the glass substrate and found to be highly efficient in absorbing infra-red radiations for potential architectural applications. Therefore, the study demonstrated the facile usage of gold nanotriangles for optical coatings. The present strategy depicted the dual functional ability of the fish scale extract as reducing and stabilising agents. This strategy also eliminates the usage of hazardous chemicals, toxic solvents and harsh reducing and stabilizing agents.

  14. Preparation of Gold-Silver Alloy Nanoparticles Supported on NiCo2O4 Spinel Oxides for the Treatment of CO in Atmosphere.

    Chinh, Vu Duc; Trung, Nguyen Quoc


    Heterometallics are an important class of catalysts. Alloy nanoparticles have higher activities than monometallic counterparts in catalysis because of the synergistic effects between the two metals. The Ni-Co composition, which is a typical alloy chemical composition, has a remarkable effect on catalytic activity. Ni-Co mixed oxides were characterized by thermal effect, X-ray diffraction, energy dispersive X-ray spectroscopy, Scanning Electron Microscope and BET specific surface area techniques. X-ray diffraction show that the formation of small spinel oxides nanoparticles. Very small amounts of gold-silver alloy nanoparticles deposited on such mixed oxides improve the catalytical activity for CO oxidation.

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

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


    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.

  16. How to detect gold, silver and mercury in human brain and other tissues by autometallographic silver amplification.

    Danscher, G; Stoltenberg, M; Juhl, S


    Gold, silver, mercury and zinc bind chemically to sulphide or selenide ions and create crystal lattices that can be detected in histological sections by a silver amplification technique called autometallography (AMG). The technique specifically magnifies such nanometer-sized catalytic crystals. For each metal, a detailed protocol has been worked out. If several different AMG metals/metal molecules are present in the same tissue, it is possible to distinguish one from another. The AMG technique is based on the capability of small crystal lattices of the aforementioned metals and metal molecules to initiate AMG silver amplification. Electrons released from adhering hydroquinone molecules reduce silver ions that are integrally connected with the crystal lattices. In this manner, particles consisting of only a few atoms of, say, gold, or molecules of mercury selenide (Figure 1), can be silver amplified to a size at which they can be detected in the electron microscope, or even further to dimensions that can be observed in the light microscope. Thus the AMG technique opens up the possibility of visualizing gold, e.g. in the nervous system of rheumatic patients who have been treated with aurothiomalate. Mercury can similarly be visualized in tissues from individuals who have been exposed to mercury, either through leaching from amalgam dental fillings, through eating fish, or by occupational exposure, and silver in the central (CNS) and peripheral nervous systems (PNS) and other tissues from individuals exposed to silver in one form or another. In the future, the possibility of demonstrating vesicular zinc, a particular pool of endogenous zinc that is found in terminals of zinc-enriched neurons (ZEN neurons), might prove valuable for pathological interpretation of diseases such as Alzheimer's disease. The vesicular zinc, present in some of the synaptic vesicles of ZEN neuron terminals, is most impressively demonstrated by AMG in telencephalic structures. It is becoming

  17. Secondary precious metal enrichment by steam-heated fluids in the Crofoot-Lewis hot spring gold-silver deposit and relation to paleoclimate

    Ebert, S.W.; Rye, R.O.


    The Crofoot-Lewis deposit is an adularia-sericite-type (low-sulfidation) epithermal Au-Ag deposit, whose well-preserved paleosurface includes abundant opaline sinters, widespread and intense silicification, bedded hydrothermal eruption breccias, and a large zone of acid sulfate alteration. Radiogenic isotope ages indicate that the system was relatively long-lived, with hydrothermal activity starting around 4 Ma and extending, at least intermittently, for the next 3 m.y. Field evidence indicates that the surficial zone of acid sulfate alteration formed in a steam-heated environment within an active geothermal system. A drop in the water table enabled descending acid sulfate waters to leach Au and Ag from zones of low-grade disseminated mineralization, resulting in the redistribution and concentration of Au and Ag into ore-grade concentrations. These zones of secondary Au-Ag enrichment are associated with opal + alunite + kaolinite + montmorillonite ?? hematite and were deposited in open space fractures at, and within a few tens of meters below, the paleowater table. The stable isotope systematics of alunite and kaolinite in the steam-heated environment are relatively complex, due to variations in the residence time of aqueous SO4 that formed from the oxidation of H2S prior to precipitation of alunite, and the susceptibility of fine-grained kaolinites to hydrogen isotope exchange with later waters. Most of the alunites are enriched in 34S relative to early sulfide minerals, reflecting partial S isotope exchange between aqueous SO4 and H2S. About half of the alunites give reasonable calculated ??18OSO4-OH temperatures for a steam-heated environment indicating O isotope equilibrium between aqueous SO4 and water. The ??5DH2O values of the hydrothermal fluids varied by almost 60 per mil over the life of the meteoric water-dominated system, suggesting significant climate changes. Mineralization is believed to have resulted from large-scale convection of meteoric water

  18. Geology and geochemistry of epithermal precious metal vein systems in the intra-oceanic arcs of Palau and Yap, western Pacific

    Rytuba, J.J.; Miller, W.R.


    -northeast. Hydrothermal alteration of the host rocks consists of a widespread weak to moderately strong propylitic alteration and a more restricted sericitic alteration adjacent to the veins and shear zones. Sulfide minerals in the veins consist primarily of pyrite accompanied by lesser amounts of sphalerite, chalcopyrite, galena, acanthite, native silver, cerargyrite, and iodyrite in partly oxidized parts of the vein system. Gold is typically fine-grained, 1-20 microns, and occurs as native gold, electrum and gold-silver-telluride. Elements correlated with high gold concentrations include molybdenum, tellurium, bismuth, lead, silver, copper, zinc and arsenic. In Yap a similar vein system to that present in Palau is hosted by the Miocene Tomil Volcanics on the islands of Maap and Gagil Tamil. The quartz veins and quartz-cemented breccias contain up to 3.7 ppm gold and trace elements associated with the gold include tellurium, copper, silver and vanadium. Within the mineralized area an unusually iron-rich (3-20%), 4-m-thick, hot-spring deposit contains up to 1.04 ppm gold and high concentrations of tellurium, copper and vanadium. Hydrothermal eruption breccia beds are present within the deposit. The presence of the hot-spring deposit and banded and comb textures of the vein quartz suggest that the vein system presently exposed formed at a shallow level. The vein systems in Palau and Yap have similar textures, geochemical suites and alteration assemblages. Both vein systems formed late in the volcanic evolution of the intra-oceanic arc. Media tested for their effectiveness in geochemical exploration in the tropical, deeply weathered environment of Palau and Yap included stream sediments, heavy-mineral concentrates from stream sediments, and sediment from the mangrove coastal environment which is well developed around most of the islands of Yap and Palau. Geochemical surveys in both Yap and Palau of mangrove sediment show that adjacent to areas of gold mineralization, gold and tellu

  19. Fluid inclusion chemistry of adularia-sericite epithermal Au-Ag deposits of the southern Hauraki Goldfield, New Zealand

    Simpson, Mark P.; Strmic Palinkas, Sabina; Mauk, Jeffrey L.; Bodnar, Robert J.


    Microthermometry, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), and Raman spectroscopy have been used to determine the temperature, apparent salinity, and composition of individual fluid inclusions in adularia-sericite Au-Ag epithermal veins from the Karangahake, Martha, Favona, and Waitekauri deposits, southern Hauraki goldfield, New Zealand. Quartz veins contain colloform to crustiform bands that alternate with coarse-grained quartz and amethyst. The ore mineralization occurs only in colloform to crustiform bands.

  20. La mineralización epitermal Miocena delcomplejo estratovolcánico Quevar, Salta: Parte 1: Geología y petrología. Parte 2: La mineralización The Miocene epithermal mineralization of the Quevar Stratovolcan Complex, Salta

    Klaus Robl


    Full Text Available El Complejo Volcánico Quevar está situado en la Puna, a unos 200 kilómetros al oeste de la ciudad de Salta, y cubre una superficie de aproximadamente 1500 km². Al sudoeste del estratovolcán se sitúan las minas Vince, Armonía y Quespejahuar con paragénesis de Ag-Pb (Sb,As,Bi. La geología regional incluye una gran variedad de de unidades de edades desde el Precámbrico a reciente. En el valle de Incahuasi, durante el Mioceno Superior, se situó un volcanismo dacítico a andesítico rico en K, a lo largo del lineamiento Calama-Olacapato-El Toro, que se manifiesta por capas de ignimbritas seguidos por el emplazamiento de grandes estratovolcanes, como por ejemplo el Quevar. En esta área se localizan dacitas (riodacitas y andesitas pertenecientes a la unidad Dacita Principal, que actúa de roca hospedante de las mineralizaciones. La zona de alteración, que se encuentra al SO del estratovolcán, cubre un área de unos 50 km² y aflora sobre una distancia vertical de 1000 m. La mena se halla en vetas, venillas, bolsones y diseminada. Se pueden distinguir dos estadios; el primero se caracteriza por una paragénesis muy compleja de sulfuros y sulfosales de Ag localizados en el oeste de la mina Armonía dentro de una brecha muy silicificada. El contenido de Sb, As y Bi es muy variable en cada especie. El segundo estadio presenta una paragénesis de Pb- Zn (Sb-As y se halla a lo largo de toda la quebrada. Estas mineralizaciones corresponde posiblemente al extremo sur de la provinciametalogenética polimetálica de Bolivia.The epithermal system of the Incahuasi Valley contains the three Ag-Pb-Zn mines of Vince, Armonía and Quespejahuar. They are located on the SW side of the Quevar Stratovolcan Complex, in the Puna, NW Argentina, and covers approx. 1500 km². The geology of the region includes a variety of lithologic units varying in age from the Precambric to present. During the Upper Miocene K-rich dacitic to andesitic volcanism occured along

  1. Subaqueous environment and volcanic evolution of the Late Cretaceous Chelopech Au-Cu epithermal deposit, Bulgaria

    Chambefort, Isabelle; Moritz, Robert


    A detailed field and petrographic study constrains the volcanic evolution and environment setting of the volcano-sedimentary-hosted Chelopech Cu-Au epithermal deposit, Bulgaria. Magmatic activity and associated high-sulfidation epithermal mineralization occurred at about 91 Ma in the Panagyurishte ore district of the Eastern European Banat-Timok-Srednogorie metallogenic belt. Volcanic and hydrothermal activity took place in a complex subaqueous setting, resulting in the intercalation of quartz sandstone with andesitic volcanic and volcaniclastic breccia. There are also hypabyssal andesite intrusion, phreatomagmatic breccia and interbeds of pyroclastic, oolithic and bioclastic rocks. The presence of altered cerebroid ooid-bearing sedimentary units characteristic of salty environment is in accordance with a lagoon environment predating the mineralization at Chelopech. Four principal stages of evolution for the Chelopech district are proposed based on field and petrographic observations. Initial volcanism occurred in a lake or in a coastal, shallow lagoon environment above crystalline basement. The Chelopech "phreatomagmatic" breccia and subsurface andesites were emplaced at this time. Subsequent hydrothermal activity produced the different hydrothermal breccia types, advanced argillic and quartz-phyllic alteration, and Au-Cu vein and replacement mineralization. The end of volcanism and hydrothermal activity was associated with opening of a pull-apart basin that covered the Chelopech environment with a sedimentary flysch. Tertiary compression faulting juxtaposed various rocks and tilted the ore deposit during the Alpine orogeny.

  2. Enhanced plastic neutron shielding for thermal and epithermal neutrons

    Palomino, L A RodrIguez; Blostein, J J; Dawidowski, J [Consejo Nacional de Investigaciones CientIficas y Tecnicas, Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de EnergIa Atomica, Universidad Nacional de Cuyo, (8400) Bariloche, Av. Bustillo 9500, S. C. de Bariloche, RIo Negro (Argentina); Cuello, G J [Institut Laue Langevin, 6, rue Jules Horowitz, F-38042 Grenoble Cedex 9 (France)], E-mail:


    We describe a compound made of paraffin and boron carbide (boraffin) deviced to enhance epithermal neutron shielding. The compound is easily prepared and is specially suited to be adapted to particular surfaces. Transmission experiments show a favourable comparison with a commercial rubber-boron carbide compound in the epithermal range. A detector shielding built with this material is described and the achieved background reduction experimentally determined is shown.

  3. Minerals

    Vaquero, M. P.


    Full Text Available The possible changes in the mineral composition of food during frying could be the consequence of losses by leaching, or changes in concentrations caused by exchanges between the food and culinary fat of other compounds. The net result depends on the type of food, the frying fat used and the frying process. Moreover, the modifications that frying produces in other nutrients could indirectly affect the availability of dietary minerals. The most outstanding ones are those that can take place in the fat or in the protein. With respect to the interactions between frying oils and minerals, we have recent knowledge concerning the effects of consuming vegetable oils used in repeated fryings of potatoes without turnover, on the nutritive utilization of dietary minerals. The experiments have been carried out in pregnant and growing rats, which consumed diets containing, as a sole source of fat, the testing frying oils or unused oils. It seems that the consumption of various frying oils, with a polar compound content lower or close to the maximum limit of 25% accepted for human consumption, does not alter the absorption and metabolism of calcium, phosphorous, iron or copper. Magnesium absorption from diets containing frying oils tends to increase but the urinary excretion of this element increases, resulting imperceptible the variations in the magnesium balance. The urinary excretion of Zn also increased although its balance remained unchanged. Different studies referring to the effects of consuming fried fatty fish on mineral bioavailability will also be presented. On one hand, frying can cause structural changes in fish protein, which are associated with an increase in iron absorption and a decrease in body zinc retention. The nutritive utilization of other elements such as magnesium, calcium and copper seems to be unaffected. On the other hand; it has been described that an excess of fish fatty acids in the diet produces iron depletion, but when fatty

  4. 青海某铁帽型金银矿石氰化浸出试验研究%The Experimental Study on Cyanidation Leaching of a Gossan Type Gold-Silver Ores in Qinghai Province



    为开发利用铁帽型金银矿产资源,对青海某铁帽型金银矿石进行了氰化法浸出试验研究,考察了磨矿细度、浸出时间、矿浆浓度、NaCN 用量、石灰用量和醋酸铅用量等因素对金银浸出率的影响,进而确定了最佳浸出条件。试验结果表明:在磨矿细度-0.074 mm 占98.23%,矿浆浓度33.33%,石灰用量10 kg/t,氰化钠用量2.5 kg/t,醋酸铅用量100 g/t 以及浸出时间24 h 条件下,该矿石中金、银浸出率分别达到93%和83%以上。该研究成果为青海某铁帽型金银矿的开发利用提供了技术支撑,并对同类型矿石资源的高效开发具有重要的借鉴意义。%In order to develop and utilize mineral resources in gossan type gold and silver ores,cyanide leaching was applied to study the gossan type gold and silver ores in Qinghai Province.We investigated the effect of grinding fineness,leaching time,pulp density,dosage of sodium cyanide,lime and lead acetate to leaching rate for gold and silver,finally the optimum leaching condition was determined.The results showed that grinding fineness of -0.074 mm accounted for 98.23%,pulp density around 33.33%,lime dosage of 10 kg/t,the dosage of sodium cyanide of 2.5 kg/t,lead acetate of 100 g/t,and under the leaching time of 24 h,the leaching rate of gold and silver was above 93% and 83%,respectively.The results provided technical support for the development and utilization of gossan type gold silver ores in Qinghai Province,and it is of great significance for the efficient development of the same kind of resource.

  5. Preliminary mineralogical data on epithermal ore veins associated with Rosia Poieni porphyry copper deposit, Apuseni Mountains, Romania

    Iatan, E. L.; Popescu, Gh. C.


    Rosia Poieni is the largest porphyry copper (±Au±Mo) deposits associated with Neogene magmatic rocks from the South Apuseni Mountains, being located approximately 8 km northeast of the town of Abrud. During a recent examination of some epithermal mineralized veins, crosscutting the porphyry mineralization from the Roşia Poieni deposit, two species of tellurides and one tellurosulfide minerals were identified. The studied samples were collected from the + 1045 m level, SW side of the open pit and are represented by epithermal veins, crosscutting the porphyry copper mineralized body. The thickness of the veins is almost 4 cm. Following reflected-polarized light microscopy to identify the ore-mineral assemblages, the polished sections were studied with a Scanning Electron Microscope (SEM) equipped with a back-scattered electron (BSE) detector to study fine-sized minerals. Quantitative compositional data were determined using a Cameca SX 50 electron microprobe (EMP). Based on optical microscopy, SEM and EMPA three mineral associations have been separated inside the epithermal vein, from the margins to the centre: 1. quartz+tennantite-tetrahedrite+goldfieldite+pyrite+sphalerite; 2. quartz+pyrite+tellurobismutite; 3. chalcopyrite+hessite+vivianite. Goldfieldite occurs in anhedral grains and it is associated with tennantite-tetrahedrite and quartz. The electron microprobe analysis gave a variable content in Te between 13.28-13.39 wt.%, 43.34 wt.% Cu, 0.1 wt. % Fe, 0.2 wt.% Zn, 14.68 wt.% As, 4.35 wt.% Sb and 24.84 wt.% S. The calculated formula for the goldfieldite is Cu11.8Te1.8(Sb,As)4S13.4. The EPM analyses on tetrahedrite-tennantite revealed a low content in Te (0.02-0.03 wt.%) and 42.23 wt.% Cu, 2.67 wt.% Fe, 7.34 wt.% Zn, 0.04 wt.% Sb, 19.28 wt.% As and 28.4 wt.% S. The calculated formula is Cu9.8(Fe,Zn)2.4(Sb,As,Te)3.8S13. The variable ratio of the Te content may reflect a variable content of Te in the hydrothermal fluids from which the tellurian tetrahedrite

  6. Processes of Defragmentation, Thermocapillary Extraction and Agglomeration of Ultradispersed Gold from Mineral Raw Materials and Technogenic Products within Laser Radiation Field

    A.P. Kuzmenko


    Full Text Available According to the analysis of the results of complex studies of mineral raw materials and man-handle products containing ultra-dispersed gold, silver, and platinum before and after laser treatment, a qualitative physical model which explains the origin of thermal processes occurring under the action of laser radiation is proposed. It is noted that laser treatment of those materials generates processes of defragmentation, thermocapillary extraction, and agglomeration of micro-and nanoinclusions of these metals.

  7. Broadband optical absorption enhancement of N719 dye in ethanol by gold-silver alloy nanoparticles fabricated under laser ablation technique

    Al-Azawi, Mohammed A.; Bidin, Noriah; Abbas, Khaldoon N.; Bououdina, Mohamed; Azzez, Shrook A.


    The formation of gold-silver alloy nanoparticles (Au-Ag alloy NPs) by a two-step process with a pulsed Nd:YAG laser without any additives is presented. Mixtures of Au and Ag colloidal suspensions were separately obtained by 1064-nm laser ablation of metallic targets immersed in ethanol. Subsequently, the as-mixed colloidal suspensions were reirradiated by laser-induced heating at the second-harmonic generation (532 nm) for different irradiation periods of time. The absorption spectra and morphology of the colloidal alloys were studied as a function of exposure time to laser irradiation. Transmission electron microscopy revealed the formation of monodispersed spherical nanoparticles with a homogeneous size distribution in all the synthesized samples. UV-vis and photoluminescence spectroscopy measurements were also employed to characterize the changes in the light absorption and emission of N719 dye solution with different concentrations of Au-Ag colloidal alloys, respectively. The localized surface plasmon resonance (LSPR) of Au-Ag alloy NPs enhanced the absorption and fluorescence peak of the dye solution. The mixture of dye molecules with a higher concentration of alloy NPs exhibited an additional coupling of dipole moments with the LSPR, thereby contributing to the improvement of the optical properties of the mixture.

  8. Site-Selective Controlled Dealloying Process of Gold-Silver Nanowire Array: a Simple Approach towards Long-Term Stability and Sensitivity Improvement of SERS Substrate

    Wiriyakun, Natta; Pankhlueab, Karuna; Boonrungsiman, Suwimon; Laocharoensuk, Rawiwan


    Limitations of achieving highly sensitive and stable surface-enhanced Raman scattering (SERS) substrate greatly concern the suitable method for fabrication of large-area plasmonic nanostructures. Herein we report a simple approach using template-based synthesis to create a highly ordered two-dimensional array of gold-silver alloy nanowires, followed by the controlled dealloying process. This particular step of mild acid etching (15%v/v nitric acid for 5 min) allowed the formation of Raman hot spots on the nanowire tips while maintaining the integrity of highly active alloy composition and rigid nanowire array structure. Full consideration of SERS substrate performance was accomplished using 4-mercaptobenzoic acid (4-MBA) as a probe molecule. Exceedingly higher SERS signal (150-fold) can be achieved with respect to typical gold film substrate. Moreover, an excellent stability of SERS substrate was also determined for over 3 months storage time. In contrast to the previous studies which stability improvement was accomplished at a cost of sensitivity reduction, the simultaneous improvement of sensitivity and stability makes the controlled dealloying process an excellent choice of SERS substrate fabrication. In addition, uniformity and reproducibility studies indicated satisfactory results with the acceptable values of relative standard deviation.

  9. Phototodynamic activity of zinc monocarboxyphenoxy phthalocyane (ZnMCPPc) conjugated to gold silver (AuAg) nanoparticles in melanoma cancer cells

    Manoto, Sello L.; Oluwole, David O.; Malabi, Rudzani; Maphanga, Charles; Ombinda-Lemboumba, Saturnin; Nyokong, Tebello; Mthunzi-Kufa, Patience


    Photodynamic therapy (PDT) is a minimally invasive therapeutic modality for the treatment of neoplastic and non-neoplastic diseases. In PDT of cancer, irradiation with light of a specific wavelength leads to activation of a photosensitizer which results in generation of reactive oxygen species (ROS) which induces cell death. Many phthalocyanine photosensitizers are hydrophobic and insoluble in water, which limits their therapeutic efficiency. Consequently, advanced delivery systems and strategies are needed to improve the effectiveness of these photosensitizers. Nanoparticles have shown promising results in increasing aqueous solubility, bioavailability, stability and delivery of photosensitizers to their target. This study investigated the photodynamic activity of zinc monocarboxyphenoxy phthalocyanine (ZnMCPPc) conjugated to gold silver (AuAg) nanoparticles in melanoma cancer cells. The photodynamic activity of ZnMCPPc conjugated to AuAg nanoparticles were evaluated using cellular morphology, viability, proliferation and cytotoxicity. Untreated cells showed no changes in cellular morphology, proliferation and cytotoxicity. However, photoactivated ZnMCPPc conjugated to AuAg nanoparticles showed changes in cell morphology and a dose dependent decrease in cellular viability, proliferation and an increase in cell membrane damage. The ZnMCPPc conjugated to AuAg nanoparticles used in this study was highly effective in inducing cell death of melanoma cancer cells.

  10. Iron isotope constraints on the mineralization processes of the Sandaowanzi telluride gold deposit, NE China

    Li, Xingxing; Liu, Junlai; Lu, Di; Ren, Shunli; Liu, Zhengyang


    Iron isotopes have been widely applied to interpret the fluid evolution, supergene alteration and the metallogenic material sources of the hydrothermal deposit. It may also have significant potentials on the research of the deposit. The Sandaowanzi telluride gold deposit, located in the Great Hinggan Range metallogenic Belt in NE China, is a large epithermal gold deposit of low-sulphidation type. It has a total reserve of ≥25t of Au and an average of 15 g/t. Gold-bearing quartz veins or gold lodes strike to the NW and dip 50-80°northeastward. Ore bodies, including low-grade ores along margins and high-grade ores in the central parts, principally occur in quartz veins. More than the 95 percent Au budgets are hosted in gold-silver tellurides. A six-stage paragenetic sequence of mineralization is revealed according to the compositions and microstructures of the mineral assemblages. Although sulfide minerals in the bonanza quartz veins are rare, pyrite are widespread in quartz veins and altered host rocks. Meanwhile there are always chalcopyrite veins within bonanza quartz veins. Pyrite Fe isotope compositions from different levels (from +50m to +210m) of the main ore body of the Sandaowanzi gold ore deposit are investigated. There is an overall variation in δ57Fe values from -0.09 to +0.99 (av. 0.33). Among them, twenty three samples from different mining levels give positiveδ57Fe values, with the maximum positive value at the economic bonanza ores (level +130m). Four samples, however, possess negative values, one at level 170m, one at level 130m, and two at level 50m, respectively. The two negative values from the levels 170m and 130m are near the cores of the high grade ore body. The two negative values from the level 50m occur at one end of the lode ore body. The above data set shows that the δ57Fe values are not homogeneous at different levels of the ore body. On the other hand, a general trend for the positive values is that the highest δ57Fe value is

  11. An accelerator-based epithermal photoneutron source for BNCT

    Nigg, D.W.; Mitchell, H.E.; Harker, Y.D.; Yoon, W.Y. [and others


    Therapeutically-useful epithermal-neutron beams for BNCT are currently generated by nuclear reactors. Various accelerator-based neutron sources for BNCT have been proposed and some low intensity prototypes of such sources, generally featuring the use of proton beams and beryllium or lithium targets have been constructed. This paper describes an alternate approach to the realization of a clinically useful accelerator-based source of epithermal neutrons for BNCT that reconciles the often conflicting objectives of target cooling, neutron beam intensity, and neutron beam spectral purity via a two stage photoneutron production process.

  12. Raman spectroscopic study of alunite occurrences in the Sapes porphyry-epithermal deposit, NE Greece

    Papazotos, Panagiotis; Perraki, Maria; Voudouris, Panagiotis; Skliros, Vasilios


    The Sapes area, Northeastern Greece, represent a deeply eroded Oligocene volcanic edifice built up of post-collisional intermediate-to-acidic intrusives and their volcanic equivalents. The area hosts a telescoped porphyry-epithermal system and associated high-sulfidation epithermal Au-Ag-Cu-Bi-Te mineralization within advanced argillic alteration lithocaps (Voudouris, 2014). Alunite is a common mineralogical constituent among the advanced argillic alteration assemblages and it is a hydrated aluminium potassium sulfate mineral with a general formula KAl3(SO4)2(OH)6. The objective of this work is to study the alunites samples in the Sapes porphyry-epithermal deposit by means of Raman spectroscopy, as it has been shown to be a useful tool in studying the alunite structure, either natural or synthetic (Frost et al., 2006; Maubec et al., 2012). Raman spectra were excited employing a 532 nm laser at a resolution of 2 cm-1 in the range of 100-4000 cm-1. Raman spectra exhibit distinguished bands at 162 cm-1, attributed to translational mode of cations and or librational and translational modes of SO42-, at 235 cm-1 suggesting framework deformations including the SO42- entities as a whole or attributed to OH/O hydrogen bond stretching mode, a weak band at 385 cm-1 may corresponding to Al-OH stretching vibrations, a moderate band at 564 cm-1 assigned to Al-O and OH deformation modes, bands at 484 and 653 cm-1 respectively due to v2(SO42-) and v4(SO42-) bending modes, a very strong vibration at 1025 cm-1 that is ascribed to the v1 stretching vibration of the SO42- bands located at 1080 and 1186 cm-1 due to v3(SO42-) stretching modes and finally two bands at 3480 cm-1 and 3502 cm-1 that are assigned to the OH stretching vibrations (Breitinger et al., 1997; Frost et al., 2006; Maubec et al., 2012 and references therein). A Raman and FTIR spectroscopic future work will focus on the comparative study among the alunites occurrences in Greece (Sapes, Limnos, Lesvos and Milos), so

  13. Measurement of epithermal neutrons by a coherent demodulation technique

    Horiuchi, N; Takahashi, H; Kobayashi, H; Harasawa, S


    Epithermal neutrons have been measured using a neutron dosimeter via a coherent demodulation technique. This dosimeter consists of CsI(Tl)-photodiode scintillation detectors, four of which are coupled to neutron-gamma converting foils of various sizes. Neutron-gamma converting foils of In, Au and Co materials were used, each of which has a large capture cross section which peaks in the epithermal neutron energy region. The type of foil was selected according to the material properties that best correspond to the energy of the epithermal neutrons to be measured. In addition, the proposed technique was applied using Au-foils in order to measure the Cd ratio. The validity of the proposed technique was examined using an sup 2 sup 4 sup 1 Am-Be source placed in a testing stack of polyethylene blocks, and the results were compared with the theoretical values calculated by the Monte Carlo calculation. Finally, the dosimeter was applied for measuring epithermal neutrons and the Cd ratio in an experimental beam-tube o...

  14. Gold-silver mining districts, alteration zones, and paleolandforms in the Miocene Bodie Hills Volcanic Field, California and Nevada

    Vikre, Peter G.; John, David A.; du Bray, Edward A.; Fleck, Robert J.


    The Bodie Hills is a ~40 by ~30 kilometer volcanic field that straddles the California-Nevada state boundary between Mono Lake and the East Walker River. Three precious metal mining districts and nine alteration zones are delineated in Tertiary-Quaternary volcanic and Mesozoic granitic and metamorphic rocks that comprise the volcanic field. Cumulative production from the mining districts, Bodie, Aurora, and Masonic, is 3.4 million ounces of gold and 28 million ounces of silver. Small amounts of mercury were produced from the Potato Peak, Paramount-Bald Peak, and Cinnabar Canyon-US 395 alteration zones; a native sulfur resource in the Cinnabar Canyon-US 395 alteration zone has been identified by drilling. There are no known mineral resources in the other six alteration zones, Red Wash-East Walker River, East Brawley Peak, Sawtooth Ridge, Aurora Canyon, Four Corners, and Spring Peak. The mining districts and alteration zones formed between 13.4 and 8.1 Ma in predominantly ~15–9 Ma volcanic rocks of the Bodie Hills volcanic field. Ages of hydrothermal minerals in the districts and zones are the same as, or somewhat younger than, the ages of volcanic host rocks.

  15. The Colors and Chromatic Charts of Gold -Silver -Copper Carat Alloys%Au-Ag-Cu系开金合金的颜色与色度图



    颜色和色度坐标是珠宝饰品设计与制造的重要因素与参数.Au- Ag-Cu系合金是最重要的颜色开金饰品合金.文章评述了Ag、Cu对Au和Au基合金的光反射率和颜色的影响;介绍了Au- Ag-Cu系合金的色度图、金合金色泽标准及某些标准颜色合金成分;讨论了某些合金化元素对Au- Ag-Cu系合金颜色的影响.通过调整Ag、Cu组元含量比例和添加其它合金化元素,Au-Ag - Cu系开金合金可以获得丰富多彩的颜色,对于设计与控制珠宝饰品的颜色有重要意义.%Au - Ag - Cu system alloys are the most important color jewelry alloys. The colors of Au - Ag - Cu alloys depend on the composition and the content of the alloying components. The influences of Ag and Cu components on the reflectivity and color of gold and gold - based alloys were reviewed. The chromatic charts of gold - silver - copper carat alloys, color standard of carat alloys and the compositions of some standard color gold alloys were introduced. The effects of some other alloying elements on the color of gold alloys were also discussed. Au - Ag - Cu carat alloys can develop rich and varied colors through regulating the ratio of the contents of Ag and Cu in alloys and adding other alloying elements, which is the basis for designing and controlling colors of carat alloys based on gold.

  16. Combining multiple correspondence analysis with factorial kriging analysis for geochemical mapping of the gold-silver deposit at Marrancos (Portugal)

    Reis, A.P.; Sousa, A.J.; Ferreira da Silva, E.; Patinha, C.; Fonseca, E.C


    This study concerns the application of multiple correspondence analysis and factorial kriging analysis to soil data, and aims to identify spatial patterns and superficial soil anomalies of the Au and Ag deposit at Marrancos, Vila Verde. The mineral deposit can be described as a quartz auriferous shear-zone, consisting of a quartz breccia of tectonic origin hosted by metamorphic rocks (hornfels). Gold is associated with arsenopyrite and pyrite, and Ag with galena and galenobismuthite. A total of 286 soil samples were analysed for Fe, Cu, Zn, Pb, Co, Ni, Mn, Ag and Bi by atomic absorption spectrometry, As, Se, Te and Sb by atomic absorption spectrometry-hydride generation system and Au by inductively coupled plasma-atomic emission spectroscopy after extraction of the metal by an organic solvent (methyl-isobutylketone). The methodology used included (a) multiple correspondence analysis applied to soil data to obtain some factors that summarize geochemical information, (b) a structural analysis (variography) in order to account for spatial variability of these factors, and (c) factorial kriging analysis used to split these factors into their spatial components. This methodology allowed an efficient multi-element characterization of the spatial patterns as well as the identification and interpretation of significant anomalies, not always associated to Au-bearing geological structures.

  17. A toolkit for epithermal neutron beam characterisation in BNCT.

    Auterinen, Iiro; Serén, Tom; Uusi-Simola, Jouni; Kosunen, Antti; Savolainen, Sauli


    Methods for dosimetry of epithermal neutron beams used in boron neutron capture therapy (BNCT) have been developed and utilised within the Finnish BNCT project as well as within a European project for a code of practise for the dosimetry of BNCT. One outcome has been a travelling toolkit for BNCT dosimetry. It consists of activation detectors and ionisation chambers. The free-beam neutron spectrum is measured with a set of activation foils of different isotopes irradiated both in a Cd-capsule and without it. Neutron flux (thermal and epithermal) distribution in phantoms is measured using activation of Mn and Au foils, and Cu wire. Ionisation chamber (IC) measurements are performed both in-free-beam and in-phantom for determination of the neutron and gamma dose components. This toolkit has also been used at other BNCT facilities in Europe, the USA, Argentina and Japan.

  18. Experimental study on Fioatation for a certain gold-silver ore containing lead in Jilin province%吉林省某矿含铅金银矿石浮选工艺试验研究

    郭宏; 邢洪波; 王学哲; 任洪胜


    Experimental study on floatation is carried out for a certain gold-silver ore containing lead in Jilin province.According to the low grade of gold, silver and lead, the experimental flowsheet is chosen as follow, raw ore bulk floatation-concentrate cyanidation-leaching residue floatation for lead.Ideal recovery rates are obtained as follow, gold 83.80 %, silver 51.19 % , lead 77.91% and sulfur 73.59 %.The flowsheet can produce gold and silver on the spot, meanwhile lead and sulfur can be recovered comprehensively.%对吉林省某矿含铅金银矿石进行了浮选工艺试验研究.根据矿石性质,针对矿石中金、银、铅品位较低的特点,试验采用原矿混合浮选-精矿氰化-浸渣浮选铅工艺流程,获得回收率:金83.80%,银51.19%,铅77.91%,硫73.59%.采用该工艺流程可实现就地产金银,同时综合回收铅硫.

  19. Experimental study on comprehensive recovery of gold, silver, copper and sulphur from copper-bearing high-sulphur gold concentrate%某含铜高硫金精矿综合回收金、银、铜、硫试验研究

    贾学国; 何辉; 刘振辉; 谢建宏; 张崇辉


    某金精矿中含金36.25g/t、铜2.37%,硫46.83%。为使其中的有价元素有效回收,在其工艺矿物学研究的基础上,分别进行了全浮流程试验和重-浮联合流程试验。通过大量的试验研究,最终确定采用重-浮联合流程试验,所得选矿指标为金、银、铜在重砂、铜精矿中的总回收率分别高达96.19%、87.91%、96.45%,硫回收率100%,使得资源得到很好的综合回收和利用。%A gold concentrate contained gold of 36.25 g/t, copper of 2.37% and sulphur of 46.83%. In order to effectively recover valuable elements, single flotation process and combination process of gravity concentra- tion and flotation were separately conducted. And then the combination process of gravity concentration and flotation was determined after lots of experimental study. The recovery rate of gold, silver and copper reached 96.19%, 87.91% and 96.45% in the concentrate, and sulphur recovery rate was 100%. The mineral resources were recovered and utilized well.

  20. Gold grade of epithermal gold ore at Lamuntet, Brang Rea, West Sumbawa District, West Nusa Tenggara Province, Indonesia

    Ernawati, Rika; Idrus, Arifudin; TBMP, Himawan


    Lamuntet is one of gold ore mining area carried out by the Artisanal Small scale Gold Mining (ASGM) located in West Sumbawa, Indonesia. Most of the miners at this area are not the local miners but also those from other regions. Mineralization of this area is strong identified as low sulfidation epithermal system. There are two blocks of this mining location, namely, Ngelampar block with an area of 0.164 km2 and Song block with an area of 0.067 km2. This study was focused on Ngelampar block. The characteristic of epithermal system is the existence of quartz vein with comb, vuggy, and sugary texture. The aim of this research was to analyze the gold grade and other metals, such as Cu, Ag, Pb, As, Zn, and Hg. The research methods included literature study from previous researches, field work, laboratory work, and interpretation. The literature study was performed on previous researches with similar study area. The field work comprised of direct observation and sampling. Fieldwork was done for a week to obtain gold ore/vein. Sixteen samples were analyzed to obtain the grade of ore/metal. The Hg laboratory analysis was then performed on the six samples with the highest gold grade. Laboratory works were conducted at Intertek Jakarta by using Fire Assay (FA) for gold grade and Atomic Absorption Spectrophotometry (AAS) for Cu, Ag, Pb, As, Zn, and Hg. Results of the analysis showed the range of Au was grade (0.1 ppm - 27.8 ppm), Cu was 26 ppm -1740 ppm, Pb was 101 ppm- >4000 ppm, Zn of 73 ppm- >10,000 ppm, Ag of 3 ppm -185 ppm, As was 150 ppm-6530 ppm, and Hg of 0.08 ppm - 1.89 ppm. L1 and L15 had high grade for all values (Au, Ag, Zn, Cu, As, and Hg). Gold mineralization was formed as electrum because of Ag content is higher than 20%. Associated minerals of the samples in the study area were galena, sphalerite, arsenopyrite, and chalcopyrite which showed the characteristic of rich base metal of Pb, Zn, and Cu at LS epithermal.

  1. Structural and biological control of the Cenozoic epithermal uranium concentrations from the Sierra Peña Blanca, Mexico

    Angiboust, Samuel; Fayek, Mostafa; Power, Ian M.; Camacho, Alfredo; Calas, Georges; Southam, Gordon


    Epithermal uranium deposits of the Sierra Peña Blanca are classic examples of volcanic-hosted deposits and have been used as natural analogs for radionuclide migration in volcanic settings. We present a new genetic model that incorporates both geochemical and tectonic features of these deposits, including one of the few documented cases of a geochemical signature of biogenic reducing conditions favoring uranium mineralization in an epithermal deposit. Four tectono-magmatic faulting events affected the volcanic pile. Uranium occurrences are associated with breccia zones at the intersection of fault systems. Periodic reactivation of these structures associated with Basin and Range and Rio Grande tectonic events resulted in the mobilization of U and other elements by meteoric fluids heated by geothermal activity. Focused along breccia zones, these fluids precipitated under reducing conditions several generations of pyrite and uraninite together with kaolinite. Oxygen isotopic data indicate a low formation temperature of uraninite, 45-55°C for the uraninite from the ore body and ˜20°C for late uraninite hosted by the underlying conglomerate. There is geochemical evidence for biological activity being at the origin of these reducing conditions, as shown by low δ34S values (˜-24.5‰) in pyrites and the presence of low δ13C (˜-24‰) values in microbial patches intimately associated with uraninite. These data show that tectonic activity coupled with microbial activity can play a major role in the formation of epithermal uranium deposits in unusual near-surface environments.

  2. Genesis of Middle Miocene Yellowstone hotspot-related bonanza epithermal Au-Ag deposits, Northern Great Basin, USA

    Saunders, J. A.; Unger, D. L.; Kamenov, G. D.; Fayek, M.; Hames, W. E.; Utterback, W. C.


    Epithermal deposits with bonanza Au-Ag veins in the northern Great Basin (NGB) are spatially and temporally associated with Middle Miocene bimodal volcanism that was related to a mantle plume that has now migrated to the Yellowstone National Park area. The Au-Ag deposits formed between 16.5 and 14 Ma, but exhibit different mineralogical compositions, the latter due to the nature of the country rocks hosting the deposits. Where host rocks were primarily of meta-sedimentary or granitic origin, adularia-rich gold mineralization formed. Where glassy rhyolitic country rocks host veins, colloidal silica textures and precious metal-colloid aggregation textures resulted. Where basalts are the country rocks, clay-rich mineralization (with silica minerals, adularia, and carbonate) developed. Oxygen isotope data from quartz (originally amorphous silica and gels) from super-high-grade banded ores from the Sleeper deposit show that ore-forming solutions had δ 18O values up to 10‰ heavier than mid-Miocene meteoric water. The geochemical signature of the ores (including their Se-rich nature) is interpreted here to reflect a mantle source for the “epithermal suite” elements (Au, Ag, Se, Te, As, Sb, Hg) and that signature is preserved to shallow crustal levels because of the similar volatility and aqueous geochemical behavior of the “epithermal suite” elements. A mantle source for the gold in the deposits is further supported by the Pb isotopic signature of the gold ores. Apparently the host rocks control the mineralization style and gangue mineralogy of ores. However, all deposits are considered to have derived precious metals and metalloids from mafic magmas related to the initial emergence of the Yellowstone hotspot. Basalt-derived volatiles and metal(loid)s are inferred to have been absorbed by meteoric-water-dominated geothermal systems heated by shallow rhyolitic magma chambers. Episodic discharge of volatiles and metal(loid)s from deep basaltic magmas mixed with

  3. A novel type epithermal neutron radiography detecting and imaging system

    Balasko, M; Svab, E; Eoerdoegh, I


    The transfer technique is widely used for epithermal neutron radiography (ENR) for making images upon the object to be investigated. We propose to use instead of the photosensitive film a gamma sensitive scintillation screen (NaCe single crystal), that is monitored by a computer controlled low light level TV camera. The exposure time has been reduced to a duration of only a short fraction of that needed for the conventional transfer process. The presented ENR images consist of electronic signals that are handled by an advanced image processing and analyzing program, the Iman 1.4 version, using a task oriented video grabber.

  4. Neutron fluence depth profiles in water phantom on epithermal beam of LVR-15 research reactor.

    Viererbl, L; Klupak, V; Lahodova, Z; Marek, M; Burian, J


    Horizontal channel with epithermal neutron beam at the LVR-15 research reactor is used mainly for boron neutron capture therapy. Neutron fluence depth profiles in a water phantom characterise beam properties. The neutron fluence (approximated by reaction rates) depth profiles were measured with six different types of activation detectors. The profiles were determined for thermal, epithermal and fast neutrons.

  5. Assessment of metallic mineral resources in the Humboldt River Basin, Northern Nevada, with a section on Platinum-Group-Element (PGE) Potential of the Humboldt Mafic Complex

    Wallace, Alan R.; Ludington, Steve; Mihalasky, Mark J.; Peters, Stephen G.; Theodore, Ted G.; Ponce, David A.; John, David A.; and Berger, Byron R.; Zientek, Michael L.; Sidder, Gary B.; Zierenberg, Robert A.


    The Humboldt River Basin is an arid to semiarid, internally drained basin that covers approximately 43,000 km2 in northern Nevada. The basin contains a wide variety of metallic and nonmetallic mineral deposits and occurrences, and, at various times, the area has been one of the Nation's leading or important producers of gold, silver, copper, mercury, and tungsten. Nevada currently (2003) is the third largest producer of gold in the world and the largest producer of silver in the United States. Current exploration for additional mineral deposits focuses on many areas in northern Nevada, including the Humboldt River Basin.

  6. Recovery of gold, silver and copper from complex gold concentrate by roasting-acidic leaching-cyanidation process%焙烧-酸浸-氰化法从复杂金精矿中回收金银铜



      采用焙烧-酸浸-氰化工艺综合回收复杂金精矿中的金、银、铜.结果表明,焙烧温度、焙烧时间、焙烧添加剂种类和用量对金、银、铜浸出率影响显著.实验确定了较优工艺条件为:焙烧添加剂NaOH用量为6%,温度630℃,焙烧时间3 h,硫酸浓度1 mol/L,酸浸液固体积质量比5∶1,酸浸温度50℃,酸浸4 h,氰化纳浓度3‰,氰化浸出液固体积质量比5∶1,常温氰化72 h.在上述条件下,金、银、铜浸出率分别达到93.53%、75.37%、94.23%.%Gold, silver and copper were extracted from complex gold concentrate by roasting-acidic leaching-cyanidation process. The experimental results show that the roasting temperature, time, additive and its dosage have great influence on the leaching of gold, silver and copper. The optimal conditions were further determined as follows: NaOH dosage of 6 %(ω), roasting temperature of 630 °C, roasting time of 3 h, sulfuric acid concentration of 1 mol/L, liquid to solid ratio of 5∶1 in acidic leach, leaching temperature of 50 °C, leaching time of 4 h, sodium cyanide concentration of 3 ‰, liquid to solid ratio of 5∶1 in cyanidation, room temperature and cyanidation time of 72 h. Under above-mentioned conditions, the leaching rate of gold, silver and copper achieved at 93.53%, 75.37%and 94.23%respectively.

  7. Precious metal-bearing epithermal deposits in western Patagonia (NE Lago Fontana region), Argentina

    Lanfranchini, Mabel Elena; Etcheverry, Ricardo Oscar; de Barrio, Raúl Ernesto; Recio Hernández, Clemente


    Precious metal-bearing quartz veins occur at the northeastern sector of the Lago Fontana region in southwestern Argentina, within the context of the Andean continental magmatic arc environment. The deposits and their associated alteration zones are spatially related to a Cretaceous calc-alkaline magmatism represented by silicic dikes and hypabyssal intrusions, and hosted by a Late Jurassic to Cretaceous volcano-sedimentary sequence. The veins and related veinlets crop out discontinuously, in general terms in a NW-SE belt. The primary vein mineral assemblage is composed mostly of pyrite ± galena ± chalcopyrite > hematite ± arsenopyrite in silica gangue minerals. Chemical analyses of grab samples from selected quartz veins show as much as 5.7 ppm Au and 224 ppm Ag, as well as elevated Pb, Cu, and Zn. Hydrothermal fluids caused an innermost silicification and adularia-sericite alteration assemblage, and an external propylitic halo. Sulfur isotope values measured for sulfides (δSS from -1.90 to +1.56‰), and oxygen and hydrogen isotopes measured on quartz crystals and extracted primary fluid inclusion waters (δOO = -2.85 to +5.40‰; δDO = -106.0 to -103.4‰) indicate that mineralization probably formed from magmatic fluids, which were mixed with meteoric waters. Also, fluid inclusion data from quartz veins point out that these fluids had low salinity (1.7-4.2 wt% NaCl equiv.), and temperatures of homogenization between 180 and 325 °C. Mineralogical, petrographic and geochemical features for mineralized surface exposures indicate a typical adularia-sericite, low sulfidation epithermal system in the Lago Fontana area that represents a promising target for further exploration programs.

  8. Correlated Observations of Epithermal Neutrons and Polar Illumination for Orbital Neutron Detectors

    McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Droege, G.; Evans, L. G.; Garvin, J.; Harshman, K.; Malakhov, A.; Livengood, T.; Milikh, G. M.; Namkung, M.; Nandikotkur, G.; Neumann, G.; Smith, D.; Sagdeev, R.; Sanin, A. G.; Starr, R. D.; Trombka, J. I.


    We correlate Lunar Reconnaisance Orbiter's (LRO) Lunar Exploration Neutron Detector (LEND) and the Lunar Prospector Neutron Spectrometer's (LPNS) orbital epithermal neutron maps of the Lunar high-latitudes with co-registered illumination maps derived from the Lunar Orbiter Laser Altimeter (LOLA) topography. Epithermal neutron count rate maps were derived from the LEND: 1) Collimated Sensor for Epithermal Neutrons, CSETNI-4 2) Uncollimated Sensor for Epithermal Neutrons, SETN and the Uncollimated Lunar Prospector: 3) Low-altitude and 4) High-altitude mapping phases. In this abstract we illustrate 1) and 3) and include 2) and 4) in our presentation. The correlative study provides unique perspectives on the regional epithermal neutron fluences from the Lunar polar regions under different detector and altitude configurations.

  9. Diverse subaerial and sublacustrine hot spring settings of the Cerro Negro epithermal system (Jurassic, Deseado Massif), Patagonia, Argentina

    Guido, Diego M.; Campbell, Kathleen A.


    The Late Jurassic (~ 150 Ma) Cerro Negro volcanic-epithermal-geothermal system (~ 15 km2 area), Deseado Massif, Patagonia, Argentina, includes two inferred volcanic emission centers characterized by rhyolitic domes linked along NW-SE regional faults that are associated with deeper level Au/Ag mineralization to the NW, and with shallow epithermal quartz veins and mainly travertine surface hot spring manifestations to the SE. Some travertines are silica-replaced, and siliceous and mixed silica-carbonate geothermal deposits also are found. Five hot spring-related facies associations were mapped in detail, which show morphological and textural similarities to Pleistocene-Recent geothermal deposits at Yellowstone National Park (U.S.A.), the Kenya Rift Valley, and elsewhere. They are interpreted to represent subaerial travertine fissure ridge/mound deposits (low-flow spring discharge) and apron terraces (high-flow spring discharge), as well as mixed silica-carbonate lake margin and shallow lake terrace vent-conduit tubes, stromatolitic mounds, and volcano-shaped cones. The nearly 200 mapped fossil vent-associated deposits at Cerro Negro are on a geographical and numerical scale comparable with subaerial and sublacustrine hydrothermal vents at Mammoth Hot Springs, and affiliated with Yellowstone Lake, respectively. Overall, the Cerro Negro geothermal system yields paleoenvironmentally significant textural details of variable quality, owing to both the differential preservation potential of particular subaerial versus subaqueous facies, as well as to the timing and extent of carbonate diagenesis and silica replacement of some deposits. For example, the western fault associated with the Eureka epithermal quartz vein facilitated early silicification of the travertine deposits in the SE volcanic emission center, thereby preserving high-quality, microbial macro- and micro-textures of this silica-replaced "pseudosinter." Cerro Negro provides an opportunity to reconstruct

  10. 从高硫多金属金精矿中提取金银铜试验研究%Experimental study on extraction of gold,silver and copper from high-sulfur content and polymetallic gold concentrates

    王瑞祥; 谢博毅; 刘建华; 张焕然


    采用焙烧-酸浸-氰化工艺从高硫多金属金精矿中提取金、银、铜。其试验结果表明:在最佳条件下,金、银、铜的平均浸出率分别可达到96.56%、79.12%、91.33%。通过对比金精矿、焙砂、氰化渣中金、银的化学物相可知,硅酸盐包裹金、银不易被氰化浸出,而加入复合添加剂焙烧,硅酸盐包裹的金、银品位大幅度下降,由直接焙烧的2.05 g/t、163.35 g/t分别降到0.81 g/t、25.24 g/t。%Gold ,silver and copper are extracted from high-sulfur content and polymetallic gold concentrates by roasting-acid leaching -cyanidation process .It is revealed that under optimal conditions the leaching rates of gold , silver and copper were respectively were 96.56%,79.12%and 91.33%.By comparing the chemical phase of gold and silver in gold concentrates ,calcines and cyanidation slags ,it is known that the gold and silver encapsulated in sili-cates are difficult to leach by cyanide ,but with composite additive in roasting ,the amount of gold and silver encapsula-ted in silicates is greatly reduced obviously ,from 2.05 g/t,163.35 g/t respectively to 0.18 g/t,25.24 g/t.

  11. Noble gas data from Goldfield and Tonopah epithermal Au-Ag deposits, ancestral Cascades Arc, USA: Evidence for a primitive mantle volatile source

    Manning, Andrew H.; Hofstra, Albert H.


    The He, Ne, and Ar isotopic composition of fluid inclusions in ore and gangue minerals were analyzed to determine the source of volatiles in the high-grade Goldfield and Tonopah epithermal Au-Ag deposits in southwestern Nevada, USA. Ar and Ne are mainly atmospheric, whereas He has only a minor atmospheric component. Corrected 3He/4He ratios (with atmospheric He removed) range widely from 0.05 to 35.8 times the air 3He/4He ratio (RA), with a median of 1.43 RA. Forty-one percent of measured 3He/4He ratios are ≥4 RA, corresponding to ≥50% mantle He assuming a mantle ratio of 8 RA. These results suggest that mafic magmas were part of the magmatic-hydrothermal system underlying Goldfield and Tonopah, and that associated mantle-sourced volatiles may have played a role in ore formation. The three highest corrected 3He/4He ratios of 17.0, 23.7, and 35.8 RAindicate a primitive mantle He source and are the highest yet reported for any epithermal-porphyry system and for the Cascades arc region. Compiled 3He/4He measurements from epithermal-porphyry systems in subduction-related magmatic arcs around the world (n = 209) display a statistically significant correlation between 3He/4He and Au-Ag grade. The correlation suggests that conditions which promote higher fluid inclusion 3He/4He ratios (abundance of mantle volatiles and focused upward volatile transport) have some relation to conditions that promote higher Au-Ag grades (focused flow of metal-bearing fluids and efficient chemical traps). Results of this and previous investigations of He isotopes in epithermal-porphyry systems are consistent with the hypothesis posed in recent studies that mafic magmas serve an important function in the formation of these deposits.

  12. Erosion level of the epithermal Rogovik deposit estimated from geochemical data, northeast Russia

    Kravtsova, R. G.; Makshakov, A. S.


    The geochemical zoning of the Rogovik epithermal deposit in northeast Russia has been established on the basis of endogenic anomalous geochemical fields (AGCF) of Au-Ag zones, their qualitative and quantitative compositions, and spatial distribution of chemical element indicators of Au-Ag mineralization. The obtained geochemical data (monoelemental AGCF, associations of elements, their composition, contrast, and correlation) allowed us to estimate the erosion level of Au-Ag ore zones. It has been shown that AGCF related to Au-Ag mineralization are distinguished by simple component composition (Au, Ag, Hg, Sb, As, Cu, Pb, Zn) and regular spatial distribution of the elements. It has been established that the least eroded central part of the object is characterized by widespread and the most contrasting Au, Ag, Hg, Sb, and As AGCF closely related to the ore-bearing units of the deposit. The contrast of these fields gradually decreases with depth. Low-contrast Cu, Pb, and Zn AGCF typical of the footwall depth intervals and flanks of Au-Ag zones intervals appear at depth. The northern part of the area is eroded to the deepest level. The contrast of Ag, Hg, Sb, and As geochemical fields abruptly decreases here, and Cu, Pb, and Zn AGCF become widespread with depth. The relatively contrasting fields of anomalous Au concentrations develop here extremely locally and near the surface. It has been concluded that the as yet poorly explored southern part of the Rogovik deposit most likely is promising for further geological exploration and the discovery of new mineralized areas.

  13. 中国浅成低温热液金矿床%Epithermal gold deposits of China

    裘愉卓; 涂光炽; Byron R. BERGER


    Epithermal gold deposits have been found mainly in eastern China and recently in the northern Xinjiang Region.They are grouped into four bolts based on their tectonic settings and belong to three mineralization episodes. They include:(1) the Cenozoic eastern Taiwan island are belt; (2) the Late Paleozoic North Xinjiang island arc bolt; (3) the Mesozoic continental margin bolt along the northern border of the Sino-Korean Craton; and (4) the Mesozoic continental margin belt of SE China coastal area. Most of the reviewed deposits are of low snlfidation type, three are of high sulfidation type, and one is of Au-Te type related to alkaline rock series. Except the Chinkuashih deposit, the largest gold deposit in China, the epithermal gold deposits in general are of less economic importance at present in the mainland of China. The total reserve of epithennal gold deposits discovered in eastern China is not compared with the huge volume of widespread subaerial volcanic rocks of Mesozoic age. Relatively old mineralization age, Mesozoic in eastern China and Late Paleozoic in North Xinjiang, is an apparent feature of epithermal gold deposits in the mainland of China. Based on the analyses of metallogenic condition and preservation in China, and the comparison with western USA and eastern Russia, a preliminary assessment on the potential of epithermal gold deposits of China has been presented. Northern Xinjiang may be potentially significant for finding epithermal gold deposits.%浅成低温热液金矿床在中国传统上称为陆相火山岩型金矿床,主要发现在中国东部,后来在北疆地区也有新的发现.根据产出的大地构造背景,它们集中分布在3个带,并分属于3个成矿时期.它们包括:(1)新生代台湾东部岛弧带;(2)晚古生代北疆岛弧带;(3)中生代沿中朝克拉通北界的大陆边缘带;(4)中生代中国东南沿海地区的大陆边缘带.绝大多数矿床是低硫化型的,只有3个是高硫化型的,另有1个是

  14. Mineral potential tracts for orogenic, Carlin-like, and epithermal gold deposits in the Islamic Republic of Mauritania, (phase V, deliverable 68): Chapter H1 in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

    Goldfarb, Richard J.; Marsh, Erin; Horton, John D.


    In 1996, at the request of the Government of the Islamic Republic of Mauritania, a team of U.S. Geological Survey (USGS) scientists produced a strategic plan for the acquisition, improvement and modernization of multidisciplinary sets of data to support the growth of the Mauritanian minerals sector and to highlight the geological and mineral exploration potential of the country. In 1999, the Ministry of Petroleum, Energy, and Mines of the Islamic Republic of Mauritania implemented a program for the acquisition of the recommended basic geoscientific information, termed the first Projet de Renforcement Institutionnel du Secteur Minier (Project for Institutional Capacity Building in the Mining Sector, PRISM-I). As a result of the PRISM-I efforts, a great deal of new geological, geophysical, geochemical, remote sensing, and hydrological data became available for evaluation and synthesis. However, the Ministry of Petroleum, Energy, and Mines recognized that additional work was required to extract the full benefit of the data before it could be of greatest use to the international community and of benefit to the Mauritanian minerals and development sector.

  15. Epithermal mercury-antimony and gold-bearing vein lodes of southwestern Alaska

    Gray, John E.; Gent, Carol A.; Snee, Lawrence W.; Wilson, Frederic H.; Goldfarb, Richard J.; Miller, Lance D.


    Epithermal mineral deposits and occurrences of southwestern Alaska consist of Hg-Sb and gold- and sulfide-bearing vein lodes. Numerous Hg-Sb lodes are located throughout a region measuring several tens of thousands of square kilometers in and surrounding the Kuskokwim River basin in southwestern Alaska. The Hg-Sb lodes are hosted in sedimentary rocks of the Cretaceous Kuskokwim Group, the Triassic to Cretaceous Gemuk Group, and the Paleozoic Holitna Group, as well as in Late Cretaceous and early Tertiary mafic to felsic intrusive rocks. Mineralized Hg-Sb vein and vein breccia lodes are found in the sedimentary or igneous rocks or at their contacts. The minerology of the Hg-Sb lodes is dominated by cinnabar and stibnite, with subordinate realgar, orpiment, and native mercury, pyrite, gold, and hematite, as well as solid and liquid hydrocarbons; quartz, carbonate, limonite, dickite, and sercite are alteration gangue minerals. The largest mercury mine in Alaska, Red Devil, produced about 36,000 flasks of mercury, but the Hg-Sb lodes of southwestern Alaska generally consist of small, discontinuous veins that rarely exceed a few meters in width and a few tens of meters in strike length. The Hg-Sb lodes generally contain about 1 to 5 percent Hg and less than 1 percent Sb and As but are generally poor in base emtals and precious metals. Anomalous concentrations of gold in some lodes, however, suggest that gold deposits may be present in higher temperature environments below some of the Hg-Sb lodes.The formation of the Hg-Sb lodes is closely correlated with igneous activity of a Late Cretaceous and early tertiary magmatic arc in southwestern Alaska. Geologic and geochemical characteristics of the Hg-Sb lodes suggest that ore fluids were generated in local sedimentary rocks as they were intruded by magmas. These intrusions provided the heat to initiate dehydration reactions and expel fluids from hydrous minerals and formational waters in the sedimentary rocks, causing

  16. Predictive mapping using GIS to locate epithermal gold deposits at Cabo de Gata (Prov. of Almeria, Spain); Cartografia predictiva mediante SIG de depositos epitermales de oro en Cabo de Gata, Almeria, Espana

    Rogol-Sanchez, J. P.; Chica-Olmo, M.; Rodriguez-Galiano, V.; Pardo-Iguzquiza, E.


    The main aim of mineral potential mapping is to generate predictive maps showing the spatial distribution of a numerical index of favour ability for the presence of a mineral deposit of the type sought. We have studied the mineral favorability for epithermal gold deposits in the Cabo de Gata volcanic field in the Province of Almeria in Spain. Predictive maps deriving from the models suggest the presence of several potentially favourable zones. The performance of predictive maps is similar in most cases. Nevertheless, data-driven methods are able to capture more readily the spatial distribution of known gold occurrences in the area. (Author) 32 refs.

  17. Estimates of iodine in biological materials by epithermal neutron activation analysis

    Sato, T. (Tokyo Metropolitan Inst. for Neurosciences, Fuchu (Japan)); Kato, T. (Tohoku Univ., Sendai (Japan). Coll. of General Education)


    Iodine abundances in NBS biological SRMs and various organs of rats were evaluated by epithermal neutron activation analysis with a boron carbide filter. The detectability of iodine in different biological materials by this method is discussed.

  18. Structural controls and evolution of gold-, silver-, and REE-bearing copper-cobalt ore deposits, Blackbird district, east-central Idaho: Epigenetic origins

    Lund, K.; Tysdal, R.G.; Evans, K.V.; Kunk, M.J.; Pillers, R.M.


    The Cu-Co ± Au (± Ag ± Ni ± REE) ore deposits of the Blackbird district, east-central Idaho, have previously been classified as Besshi-type VMS, sedex, and IOCG deposits within an intact stratigraphic section. New studies indicate that, across the district, mineralization was introduced into the country rocks as a series of structurally controlled vein and alteration systems. Quartz-rich and biotite-rich veins (and alteration zones) and minor albite and siderite veinlets maintain consistent order and sulfide mineral associations across the district. Both early and late quartz veins contain chalcopyrite and pyrite, whereas intermediate-stage tourmaline-biotite veins host the cobaltite. Barren early and late albite and late carbonate (generally siderite) form veins or are included in the quartz veins. REE minerals, principally monazite, allanite, and xenotime, are associated with both tourmaline-biotite and late quartz veins. The veins are in mineralized intervals along axial planar cleavage, intrafolial foliation, and shears.

  19. A New Genetic Type of Gold Deposits-Meso-Epithermal Carbonate-Type Gold Deposits as Exemplified by the Baguamiao Suprlarge Gold Deposit


    Gold deposits of the meso-epithermal carbonate type were first proposed based on the study of the Baguamiao gold deposit.This new type of gold deposits has many unique characteristics as follows:(1)Obviously strata-bound.The gold deposits are hosted in Middle Devonian turbidite formations;(2)Structrually controlled.Struc-ture is an important factor leading to metallogenesis of this type of gold deposits.The shape and distribution of orebodies are controlled by byittle-ductile shear zones;(3)Multi-stage wall-rock alteration.According to the characteristics of mineral assemblage,gold mineralization can be classified into three stages in association with various wall-rock al-terations.Wall-rock alterations closely genetically related to the gold mineralization are ankerization ,silicification,pyrrhotization and pyritization ;(4)Mineral compositions of the orebodies are mainly pyrrhotite,pyrite,marcasitolite,chalcopyrite,quartz,ankerite,and sericite.Gold mineralization is associated closely in space and time with iron sulfides;(5)Rare elements and REE in ores are low in contents relative to those of the crust.Au content varies from 1.91g/t to 11.15g/t ,averaging 5.5g/t;(6)Studies of sulfur,hydrogen,oxygen and carbon isotopes in main gangue minerals (quartz and ankerite)indicate that fluids and ore-forming materials came from deep-seated sources;(7)Three types of inclusions are recognized in terms of their composition and the vapor amounts of inclusions.The homogenization temperatures of inclusions range from 210℃to 310℃,averaging 230℃,showing that this type of gold deposits belongs to the meso-epithermal type;(8)Metallogenic age of this type of gold deposits is similar to that of the collision between the Yangtze Plate and the North China Plate,indicating that gold deposits of this type are genetically related to continental-margin plate activity.

  20. A spin reversal system for polarized epithermal neutrons

    Bowman, J.D. [Los Alamos Nat. Lab., NM (United States); Penttilae, S.I. [Los Alamos Nat. Lab., NM (United States); Tippens, W.B. [University of Virginia, Charlottesville, VA 22903 (United States)


    The design and construction of a spin-reversal system for longitudinally polarized epithermal neutrons are presented. The design uses a static magnetic field parallel to the momentum of the neutron. The longitudinal field changes the direction at its midpoint. A transverse magnetic field is turned off to control the spin direction at the end of the spin flipper. The neutron spin is reversed with respect to both the neutron momentum and the static longitudinal field at the exit of the spin flipper. In the transverse field-on state the spin adiabatically follows the field direction and the spin direction is reversed. In the transverse field-off state the spin passes rapidly through the region where the solenoidal field reverses the sign and the spin direction is not reversed. With this design, the spins of an 8-cm-diameter beam of longitudinally polarized neutrons can be reversed with an efficiency greater than 88% over a range of neutron energies of more than four orders of magnitude. (orig.).

  1. A spin reversal system for polarized epithermal neutrons

    Bowman, J. D.; Penttilä, S. I.; Tippens, W. B.


    The design and construction of a spin-reversal system for longitudinally polarized epithermal neutrons are presented. The design uses a static magnetic field parallel to the momentum of the neutron. The longitudinal field changes the direction at its midpoint. A transverse magnetic field is turned off to control the spin direction at the end of the spin flipper. The neutron spin is reversed with respect to both the neutron momentum and the static longitudinal field at the exit of the spin flipper. In the transverse field-on state the spin adiabatically follows the field direction and the spin direction is reversed. In the transverse field-off state the spin passes rapidly through the region where the solenoidal field reverses the sign and the spin direction is not reversed. With this design, the spins of an 8-cm-diameter beam of longitudinally polarized neutrons can be reversed with an efficiency greater than 88% over a range of neutron energies of more than four orders of magnitude.

  2. Magmatic-vapor expansion and the formation of high-sulfidation gold deposits: Chemical controls on alteration and mineralization

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


    from any external contemporary hydrothermal activity. Subsequent fracturing is localized by the embrittled wallrock to provide high-permeability fracture arrays that constrain vapor expansion with minimization of heat loss. The Sulfide Stage vein sequence is then a consequence of destabilization of metal-vapor species in response to depressurization and decrease in vapor density. The geology, mineralogy, fluid inclusion and stable isotope data and geothermometry for high-sulfidation, bulk-tonnage and lode deposits are quite different from those for epithermal gold-silver deposits such as McLaughlin, California that formed near-surface in groundwater-dominated hydrothermal systems where magmatic fluid has been diluted to less than about 30%. High sulfidation gold deposits are better termed 'Solfataric Gold Deposits' to emphasize this distinction. The magmatic-vapor expansion hypothesis also applies to the phenomenology of acidic geothermal systems in active volcanic systems and equivalent magmatic-vapor discharges on the flanks of submarine volcanoes. ?? 2010.

  3. The mineral base and productive capacities of metals and non-metals of Kosovo

    Rizaj, M.; Beqiri, E.; McBow, I.; O' Brien, E.Z.; Kongoli, F. [University of Prishtina, Prishtina (Kosovo)


    All historical periods of Kosovo - Ilirik, Roman, Medieval, Turkish, and former Yugoslavian - are linked with the intensive development of mining and metallurgy. This activity influenced and still is influencing the overall position of Kosovo as a country. For example, according to a 2006 World Bank report as well as other studies, Kosovo has potential lignite resources (geological reserves) of about 1.5 billion tonnes, which are ranked fifth in the world in importance. Other significant Kosovan mineral resources include lead, zinc, gold, silver, bauxite, and uranium, and rare metals accompanying those minerals, including indium, cadmium, thallium, gallium, and bismuth. These rare metals are of particular importance in developing advanced industrial technologies. Kosovo also has reserves of high-quality non-metals, including magnesite, quartz grit, bentonite, argil, talc, and asbestos. No database exists for these non-metal reserves, and further research and studies are needed.

  4. The mineral base and productive capacities of metals and non-metals of Kosovo

    Rizaj, M.; Beqiri, E.; McBow, I.; O'Brien, E. Z.; Kongoli, F.


    All historical periods of Kosovo—Ilirik, Roman, Medieval, Turkish, and former Yugoslavian—are linked with the intensive development of mining and metallurgy. This activity influenced and still is influencing the overall position of Kosovo as a country. For example, according to a 2006 World Bank report as well as other studies, Kosovo has potential lignite resources (geological reserves) of about 1.5 billion tonnes, which are ranked fifth in the world in importance. Other significant Kosovan mineral resources include lead, zinc, gold, silver, bauxite, and uranium, and rare metals accompanying those minerals, including indium, cadmium, thallium, gallium, and bismuth. These rare metals are of particular importance in developing advanced industrial technologies. Kosovo also has reserves of high-quality non-metals, including magnesite, quartz grit, bentonite, argil, talc, and asbestos. No database exists for these non-metal reserves, and further research and studies are needed.

  5. Renovation of epithermal neutron beam for BNCT at THOR

    Liu, Y.-W.H. E-mail:; Huang, T.T.; Jiang, S.H.; Liu, H.M


    Heading for possible use for clinical trial, THOR (Tsing Hua Open-pool Reactor) at Taiwan was shutdown for renovation of a new epithermal neutron beam in January 2003. In November 2003, concrete cutting was finished for closer distance from core and larger treatment room. This article presents the design base that the construction of the new beam is based on. The filter/moderator design along the beam is Cd(0.1 cm)+Al(10 cm)+FLUENTAL{sup TM}(16 cm)+Al(10 cm)+FLUENTAL(24 cm)+Void(18 cm)+Cd(0.1 cm)+Bi(10 cm) with 6 cm Pb as reflector. Following the filter/moderator is an 88 cm long, 6 cm thick Bi-lined collimator with Li{sub 2}CO{sub 3}-PE at the end. The collimator is surrounded by Li{sub 2}CO{sub 3}-PE and Pb. The calculated beam parameters under 2 MW at the beam exit is phi{sub epi}=3.4x10{sup 9} n/cm{sup 2}/s, D{sub f}/phi{sub epi}=2.8x10{sup -11} cGy cm{sup 2}/n, D{sub {gamma}}/phi{sub epi}=1.3x10{sup -11} cGy cm{sup 2}/n, and J{sub +}/phi= 0.8. For a phantom placed 10 cm from beam exit, MCNP calculation shows that the advantage depth is 8.9 cm, and advantage ratio is 5.6 if boron concentration in tumor and normal tissue are assumed to be 65 and 18 ppm. The maximum dose rate for normal tissue is 50 cGy/min. The maximum therapeutic ratio is 6. The construction of the beam is scheduled to be finished by the end of April 2004.

  6. Renovation of epithermal neutron beam for BNCT at THOR.

    Liu, Y-W H; Huang, T T; Jiang, S H; Liu, H M


    Heading for possible use for clinical trial, THOR (Tsing Hua Open-pool Reactor) at Taiwan was shutdown for renovation of a new epithermal neutron beam in January 2003. In November 2003, concrete cutting was finished for closer distance from core and larger treatment room. This article presents the design base that the construction of the new beam is based on. The filter/moderator design along the beam is Cd(0.1cm)+Al(10 cm)+FLUENTAL (16 cm)+Al(10 cm)+FLUENTAL(24 cm)+Void(18 cm)+Cd(0.1cm)+Bi(10 cm) with 6 cm Pb as reflector. Following the filter/moderator is an 88 cm long, 6 cm thick Bi-lined collimator with Li(2)CO(3)-PE at the end. The collimator is surrounded by Li(2)CO(3)-PE and Pb. The calculated beam parameters under 2 MW at the beam exit is phi(epi) = 3.4 x 10(9) n/cm(2)/s, Df/phi(epi) = 2.8 x 10(-11) cGy cm(2)/n, Dgamma/phi(epi) = 1.3 x 10(-11) cGy cm(2)/n, and J+/phi = 0.8. For a phantom placed 10 cm from beam exit, MCNP calculation shows that the advantage depth is 8.9 cm, and advantage ratio is 5.6 if boron concentration in tumor and normal tissue are assumed to be 65 and 18 ppm. The maximum dose rate for normal tissue is 50 cGy/min. The maximum therapeutic ratio is 6. The construction of the beam is scheduled to be finished by the end of April 2004.

  7. Epithermal Neutron Activation Analysis of the Asian Herbal Plants

    Baljinnyam, N.; Jugder, B.; Norov, N.; Frontasyeva, M. V.; Ostrovnaya, T. M.; Pavlov, S. S.


    Asian medicinal herbs Chrysanthemum (Spiraea aquilegifolia Pall.) and Red Sandalwood (Pterocarpus Santalinus) are widely used in folk and Ayurvedic medicine for healing and preventing some diseases. The modern medical science has proved that the Chrysanthemum (Spiraea aquilegifolia Pall.) possesses the following functions: reducing blood press, dispelling cancer cell, coronary artery's expanding and bacteriostating and Red Sandalwood (Pterocarpus Santalinus) is recommended against headache, toothache, skin diseases, vomiting and sometimes it is taken for treatment of diabetes. Species of Chrysanthemums were collected in the north-eastern and central Mongolia, and the Red Sandalwood powder was imported from India. Samples of Chrysanthemums (branches, flowers and leaves) (0.5 g) and red sandalwood powder (0.5 g) were subjected to the multi-element instrumental neutron activation analysis using epithermal neutrons (ENAA) at the IBR-2 reactor, Frank Laboratory of Neutron Physics (FLNP) JINR, Dubna. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Cs, Ba, La, Hf, Ta, W, Sb, Au, Hg, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Th, U, Lu) were determined. For the first time such a large group of elements was determined in the herbal plants used in Mongolia. The quality control of the analytical results was provided by using certified reference material Bowen Cabbage. The results obtained are compared to the "Reference plant» data (B. Markert, 1992) and interpreted in terms of excess of such elements as Se, Cr, Ca, Fe, Ni, Mo, and rare earth elements.

  8. Experimental demonstration of a compact epithermal neutron source based on a high power laser

    Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Raspino, D.; Ansell, S.; Wilson, L. A.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Kelleher, J.; Murphy, C. D.; Notley, M.; Rusby, D. R.; Schooneveld, E.; Borghesi, M.; McKenna, P.; Rhodes, N. J.; Neely, D.; Brenner, C. M.; Kar, S.


    Epithermal neutrons from pulsed-spallation sources have revolutionised neutron science allowing scientists to acquire new insight into the structure and properties of matter. Here, we demonstrate that laser driven fast (˜MeV) neutrons can be efficiently moderated to epithermal energies with intrinsically short burst durations. In a proof-of-principle experiment using a 100 TW laser, a significant epithermal neutron flux of the order of 105 n/sr/pulse in the energy range of 0.5-300 eV was measured, produced by a compact moderator deployed downstream of the laser-driven fast neutron source. The moderator used in the campaign was specifically designed, by the help of MCNPX simulations, for an efficient and directional moderation of the fast neutron spectrum produced by a laser driven source.

  9. The Local-time variations of Lunar Prospector epithermal-neutron data

    Teodoro, L F A; Eke, V E; Elphic, R E; Feldman, W C; Maurice, S; Siegler, M A; Paige, D A


    We assess local-time variations of epithermal-neutron count rates measured by the Lunar Prospector Neutron Spectrometer. We investigate the nature of these variations and find no evidence to support the idea that such variations are caused by diurnal variations of hydrogen concentration across the lunar surface. Rather we find an anticorrelation between instrumental temperature and epithermal-neutron count rate. We have also found that the measured counts are dependent on the temperatures of the top decimeters of the lunar subsurface as constrained by the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment temperature measurements. Finally, we have made the first measurement of the effective leakage depth for epithermal-neutrons of ~20 cm.

  10. Analytic expression for epithermal neutron spectra amplitudes as a function of water content

    Drake, Darrell


    The epithermal portion of an equilibrium neutron spectrum in a planetary body is a function of the water content of its material. The neutrons are produced at high energies but are moderated by elastic and inelastic scattering until they either are captured by surrounding nuclei or escape. We have derived an expression that explicitly shows the dependance of epithermal neutron spectra on water content. Additionally, we compared its predictions to calculations done by Boltzman transport code for infinite media for silicon, oxygen, and a possible lunar composition, and we have obtained very good agreement.

  11. Flux and instrumentation upgrade for the epithermal neutron beam facility at Washington State University.

    Nigg, D W; Venhuizen, J R; Wemple, C A; Tripard, G E; Sharp, S; Fox, K


    An epithermal neutron beam facility for preclinical neutron capture therapy research has been constructed at the Washington State University TRIGA research reactor installation. Subsequent to a recent upgrade, this new facility offers a high-purity epithermal beam with intensity on the order of 1.2x10(9)n/cm(2)s. Key features include a fluoride-based design for the neutron filtering and moderating components as well as a novel collimator design that allows ease of assembly and disassembly of the beamline components.

  12. A new monitor for routine thermal and epithermal neutron fluence rate monitoring in k0 INAA.

    Koster-Ammerlaan, M J J; Bacchi, M A; Bode, P; De Nadai Fernandes, E A


    The Zr-Au set for monitoring the thermal and epithermal neutron fluence rate and the epithermal spectrum parameter alpha is not always practicable for routine application of INAA in well-thermalized facilities. An alternative set consisting of Cr, Au and Mo provides values for the thermal neutron fluence rate, f and alpha that are not significantly different from those found via the Zr-Au method and the Cd-covered Zr-method. The IRMM standard SMELS-II was analyzed using the (Au-Cr-Mo) monitor and a good agreement was obtained.

  13. The optimization study of Bonner sphere in the epi-thermal neutron irradiation field for BNCT.

    Ueda, H; Tanaka, H; Maruhashi, A; Ono, K; Sakurai, Y


    The optimization study on the Bonner sphere in the epi-thermal neutron irradiation field for BNCT was done for the moderator material, moderator size, and activation foils as a neutron detector in the sphere. The saturated activity for the activation foil was obtained from the calculated response, and the effective energy range for each Bonner sphere was determined from the saturated activity. We can see that boric acid solution moderator is suitable for the spectrum measurement of a epi-thermal neutron irradiation field.

  14. High-value utilization of egg shell to synthesize Silver and Gold-Silver core shell nanoparticles and their application for the degradation of hazardous dyes from aqueous phase-A green approach.

    Sinha, Tanur; Ahmaruzzaman, M


    The common household material, egg shell of Anas platyrhynchos is utilized for the synthesis of Silver and Gold-Silver core shell nanoparticles using greener, environment friendly and economic way. The egg shell extracts were acting as a stabilizing and reducing agents. This method avoids the use of external reducing and stabilizing agents, templates and solvents. The effects of various reaction parameters, such as reaction temperature, concentration in the formation of nanoparticles have also been investigated. The compositional abundance of gelatin may be envisaged for the effective reductive as well as stabilizing potency. The mechanisms for the formation of NPs have also been presented. The synthesized Ag NPs formed were predominantly spherical in nature with an average size of particles in the range of 6-26 nm. While, Au-Ag core shell nanoparticles formed were spherical and oval shaped, within a narrow size spectrum of 9-18 nm. Both the Ag NPs Au-and Ag core shell nanoparticles showed characteristic Bragg's reflection planes of fcc structure and surface plasmon resonance at 430 nm and 365 nm, respectively. The NPs were utilized for the removal of toxic and hazardous dyes, such as Rose Bengal, Methyl Violet 6 B and Methylene Blue from aqueous phase. Approximately 98.2%, 98.4% and 97% degradations of Rose Bengal, Methyl Violet 6 B, and Methylene Blue were observed with Ag NPs, while the percentage degradation of these dyes was 97.3%, 97.6% and 96% with Au-Ag NPs, respectively. Therefore, the present study has opened up an innovative way for synthesizing Ag NPs and Au-Ag bimetallic nanostructures of different morphologies and sizes involving the utilization of egg shell extract. The high efficiency of the NPs as photocatalysts has opened a promising application for the removal of hazardous dyes from the industrial effluents. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Mineralogy, alteration patterns, geochemistry, and fluid properties of the Ag-Au epithermal deposit Nová Baňa, Slovakia

    Majzlan, Juraj; Berkh, Khulan; Kiefer, Stefan; Koděra, Peter; Fallick, Anthony E.; Chovan, Martin; Bakos, František; Biroň, Adrián; Ferenc, Štefan; Lexa, Jaroslav


    In this contribution, we report new data on mineralogy, alteration patterns, geochemistry, fluid properties and source of fluids for the deposit Nová Baňa, one of the smaller epithermal deposits in the Middle Miocene Štiavnica andesite stratovolcano (Western Carpathians, Slovakia). Ore veins and the associated rocks were studied in samples from outcrops and old mines, grab samples, and bore holes from the central part of the deposit (ore structures Althandel, Jozef, Jakub, Vavrinec), northern part (Freischurf), SE part (Gupňa) and SW part (Šibeničný vrch). Pervasive hydrothermal alteration transformed the rock-forming minerals into a mixture of adularia and fine-grained quartz, with lesser amount of pyrite, Ti oxides and Fe oxides. This assemblage was further altered to omnipresent interstratified illite/smectite that was used in this study as a geothermometer, corroborating the results from the fluid inclusion work. Ore minerals comprise predominantly pyrite, sphalerite, galena but all sulfides are relatively sparse in the samples studied. Minerals of precious metals are electrum, Ag-tetrahedrite, acanthite, members of the polybasite-pearceite and pyrargyrite-proustite solid solution, and rare miargyrite, Hg-Ag tetrahedrite, and diaphorite. In the central part, we have found also some stibnite. In the SE part of the deposit, acanthite, uytenbogaardtite, and petrovskaite occur and seem to be related to supergene enrichment of the ores. In bulk ore samples, Zn usually dominates over Pb and Cu. The average Ag:Au ratio for the entire deposit is 64:1. The concentrations of precious metals in the grab samples reach maxima of 50 ppm Au and 570 ppm Ag in the SE part and 116 ppm Au and 1110 ppm Ag in the central part of the deposit. Fluid inclusions show signs of trapping of a heterogeneous fluid. In the central, northern and SE parts of the deposit, homogenization temperatures of 190-260 °C and consistently low salinities of hydrothermal fluids falling between the

  16. Epithermal uranium deposits in a volcanogenic context: the example of Nopal 1 deposit, Sierra de Pena Blanca, Mexico

    Calas, G.; Angiboust, S.; Fayek, M.; Camacho, A.; Allard, T.; Agrinier, P.


    The Peña Blanca molybdenum-uranium field (Chihuahua, Mexico) exhibits over 100 airborne anomalies hosted in tertiary ignimbritic ash-flow tuffs (44 Ma) overlying the Pozos conglomerate and a sequence of Cretaceous carbonate rocks. Uranium occurrences are associated with breccia zones at the intersection of two or more fault systems. Periodic reactivation of these structures associated with Basin and Range and Rio Grande tectonic events resulted in the mobilization of U and other elements by meteoric fluids heated by geothermal activity. Trace element geochemistry (U, Th, REE) provides evidence for local mobilization of uranium under oxidizing conditions. In addition, O- and H-isotope geochemistry of kaolinite, smectite, opal and calcite suggests that argillic alteration proceeded at shallow depth with meteoric water at 25-75 °C. Focussed along breccia zones, fluids precipitated several generations of pyrite and uraninite together with kaolinite, as in the Nopal 1 mine, indicating that mineralization and hydrothermal alteration of volcanic tuffs are contemporaneous. Low δ34S values (~ -24.5 ‰) of pyrites intimately associated with uraninite suggest that the reducing conditions at the origin of the U-mineralization arise from biological activity. Later, the uplift of Sierra Pena Blanca resulted in oxidation and remobilization of uranium, as confirmed by the spatial distribution of radiation-induced defect centers in kaolinites. These data show that tectonism and biogenic reducing conditions can play a major role in the formation and remobilization of uranium in epithermal deposits. By comparison with the other uranium deposits at Sierra Pena Blanca and nearby Sierra de Gomez, Nopal 1 deposit is one of the few deposits having retained a reduced uranium mineralization.

  17. Fluid evolution in a volcanic-hosted epithermal carbonate-base metal-gold vein system: Alto de la Blenda, Farallón Negro, Argentina

    Márquez-Zavalía, M. Florencia; Heinrich, Christoph A.


    Alto de la Blenda is a ˜6.6-Ma intermediate-sulphidation epithermal vein system in the Farallón Negro Volcanic Complex, which also hosts the 7.1-Ma porphyry-Cu-Au deposit of Bajo de la Alumbrera. The epithermal vein system is characterised by a large extent and continuity (2 km × 400 m open to depth × 6 m maximum width) and an average gold grade of ˜8 g/t. The vein is best developed within an intrusion of a fine-grained equigranular monzonite, interpreted as the central conduit of a stratovolcano whose extrusive activity ended prior to porphyry-Cu-Au emplacement at Bajo de la Alumbrera, which is in turn cut by minor epithermal veins. The Alto de la Blenda vein consists predominantly of variably Mn-rich carbonates and quartz, with a few percent of pyrite, sphalerite, galena and other sulphide and sulphosalt minerals. Four phases of vein opening, hydrothermal mineralisation and repeated brecciation can be correlated between different vein segments. Stages 2 and 3 contain the greatest fraction of sulphide and gold. They are separated by the emplacement of a polymictic breccia containing clasts of quartz feldspar porphyry as well as basement rocks. Fluid inclusions in quartz related to stages 2 to 4 are liquid rich with 2-4 wt% NaCl(eq). They homogenise between 160 and 300 °C, with very consistent values within each assemblage. Vapour inclusions are practically absent in the epithermal vein. Quartz fragments in the polymictic breccia contain inclusions of intermediate to vapour-like density and similar low salinity (˜3 wt% NaCl(eq)), besides rare brine inclusions containing halite. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of epithermal inclusions indicate high concentrations of K, Fe, As, Sb, Cs, and Pb that significantly vary within and through subsequent vein stages. Careful consideration of detection limits for individual inclusions shows high gold concentrations of ˜0.5 to 3 ppm dissolved in the ore fluid, which

  18. Epithermal Neutron Evidence for a Diurnal Surface Hydration Process in the Moon's High Latitudes

    McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Parsons, A.; Starr, R. D.; Evans, L. G.; Sanin, A.; Litvak, M.; Livengood, T.


    We report evidence from epithermal neutron flux observations that show that the Moon's high latitude surfaces are being actively hydrated, dehydrated and rehydrated in a diurnal cycle. The near-surface hydration is indicated by an enhanced suppression of the lunar epithermal neutron leakage flux on the dayside of the dawn terminator on poleward-facing slopes (PFS). At 0600 to 0800 local-time, hydrogen concentrations within the upper 1 meter of PFS are observed to be maximized relative to equivalent equator-facing slopes (EFS). During the lunar day surface hydrogen concentrations diminish towards dusk and then rebuild overnight. Surface hydration is determined by differential comparison of the averaged EFS to PFS epithermal neutron count rates above +/- 75 deg latitude. At dawn the contrast bias towards PFS is consistent with at least 15 to 25 parts-per-million (ppm) hydrogen that dissipates by dusk. We review several lines of evidence derived from temperature and epithermal neutron data by a correlated analysis of observations from the Lunar Reconnaissance Orbiter's (LRO) Lunar Exploration Neutron Detector (LEND) that were mapped as a function of lunar local-time, Lunar Observing Laser Altimeter (LOLA) topography and Diviner (DLRE) surface temperature.

  19. Stable isotope variations in the Quaternary epithermal calcite-fluorite deposit at Monte delle Fate near Cerveteri (Latium, central Italy)

    Masi, U.; O'Neil, J.R.


    Carbon, oxygen and hydrogen isotope variations have been measured in samples from the epithermal fluorite vein deposit at Monte delle Fate, Latium. The ranges in ?? 13C and ??18O of calcite are -1.3 to 3.4 and 9.5 to 17.3, respectively. ??D values of water extracted from fluid inclusions are -49 to -39 for calcite and -41 to -34 for fluorite. Fluid inclusion filling temperatures (225??-240??C) and salinites (3.75) are nearly the same for both fluorite and sparry calcite. An elongated form of calcite, of minor abundance, precipitated at lower temperatures. The data indicate that (1) the CO2 involved in the mineralization was provided by the local marine limestones, (2) the waters were meteoric in origin and underwent an 18O shift of ??? 10 permil by exchange with marine country rocks, and (3) all geochemical features can be explained by the action of two hydrothermal fluids. Hot brines recently discovered in the Cesano geothermal area, 30 km to the east, have temperatures and some chemical characteristics similar to the hydrothermal fluids at Monte delle Fate. ?? 1980 Springer-Verlag.

  20. Gold grade distribution within an epithermal quartz vein system, Kestanelik, NW Turkey: implications for gold exploration

    Gulyuz, Nilay; Shipton, Zoe; Gulyuz, Erhan; Lord, Richard; Kaymakci, Nuretdin; Kuscu, İlkay


    Vein-hosted gold deposits contribute a large part to the global gold production. Discovery of these deposits mainly include drilling of hundreds of holes, collecting thousands of soil and rock samples and some geophysical surveys which are expensive and time consuming. Understanding the structures hosting the veins and the variations in gold concentrations within the veins is crucial to constrain a more economic exploration program. The main aim of this study is to investigate the gold grade distribution in the mineralized quartz veins of a well exposed epithermal gold deposit hosted by Paleozoic schist and Eocene quartz-feldspar-hornblende porphyry in Lapseki, NW Turkey. We have constructed 3D architecture of the vein surfaces by mapping their outcrop geometries using a highly sensitive Trimble GPS, collecting detailed field data, well-logs and geochemistry data from 396 drill holes (255 diamond cut and 141 reverse circulation holes). Modelling was performed in MOVE Structural Modelling and Analysis software granted by Midland Valley's Academic Software Initiative, and GIS application softwares Global Mapper and Esri-ArcGIS. We envisaged that while fluid entering the conduit ascents, a sudden thickness increase in the conduit would lead to a drop in the fluid pressure causing boiling (the most dominant gold precipitation mechanism) and associated gold precipitation. Regression analysis was performed between the orthogonal thickness values and gold grades of each vein, and statistical analyses were performed to see if the gold is concentrated at specific structural positions along dip. Gold grades in the alteration zones were compared to those in the adjacent veins to understand the degree of mineralization in alteration zones. A possible correlation was also examined between the host rock type and the gold grades in the veins. These studies indicated that gold grades are elevated in the adjacent alteration zones where high gold grades exist in the veins. Schist

  1. An accelerator-based epithermal neutron beam design for BNCT and dosimetric evaluation using a voxel head phantom.

    Lee, Deok-jae; Han, Chi Young; Park, Sung Ho; Kim, Jong Kyung


    The beam shaping assembly design has been investigated in order to improve the epithermal neutron beam for accelerator-based boron neutron capture therapy in intensity and quality, and dosimetric evaluation for the beams has been performed using both mathematical and voxel head phantoms with MCNP runs. The neutron source was assumed to be produced from a conventional 2.5 MeV proton accelerator with a thick (7)Li target. The results indicate that it is possible to enhance epithermal neutron flux remarkably as well as to embody a good spectrum shaping to epithermal neutrons only with the proper combination of moderator and reflector. It is also found that a larger number of thermal neutrons can reach deeply into the brain and, therefore, can reduce considerably the treatment time for brain tumours. Consequently, the epithermal neutron beams designed in this study can treat more effectively deep-seated brain tumours.

  2. Molecular structural analysis of HPRT mutations induced by thermal and epithermal neutrons in Chinese hamster ovary cells.

    Kinashi, Y; Sakurai, Y; Masunaga, S; Suzuki, M; Takagaki, M; Akaboshi, M; Ono, K


    Chinese hamster ovary (CHO) cells were exposed to thermal and epithermal neutrons, and the occurrence of mutations at the HPRT locus was investigated. The Kyoto University Research Reactor (KUR), which has been improved for use in neutron capture therapy, was the neutron source. Neutron energy spectra ranging from nearly pure thermal to epithermal can be chosen using the spectrum shifters and thermal neutron filters. To determine mutant frequency and cell survival, cells were irradiated with thermal and epithermal neutrons under three conditions: thermal neutron mode, mixed mode with thermal and epithermal neutrons, and epithermal neutron mode. The mutagenicity was different among the three irradiation modes, with the epithermal neutrons showing a mutation frequency about 5-fold that of the thermal neutrons and about 1.5-fold that of the mixed mode. In the thermal neutron and mixed mode, boron did not significantly increase the frequency of the mutants at the same dose. Therefore, the effect of boron as used in boron neutron capture therapy (BNCT) is quantitatively minimal in terms of mutation induction. Over 300 independent neutron-induced mutant clones were isolated from 12 experiments. The molecular structure of HPRT mutations was determined by analysis of all nine exons by multiplex polymerase chain reaction. In the thermal neutron and mixed modes, total and partial deletions were dominant and the fraction of total deletions was increased in the presence of boron. In the epithermal neutron mode, more than half of the mutations observed were total deletions. Our results suggest that there are clear differences between thermal and epithermal neutron beams in their mutagenicity and in the structural pattern of the mutants that they induce. Mapping of deletion breakpoints of 173 partial-deletion mutants showed that regions of introns 3-4, 7/8-9 and 9-0 are sensitive to the induction of mutants by neutron irradiation.

  3. Microgranular enclaves in island-arc andesites: A possible link between known epithermal Au and potential porphyry Cu-Au deposits in the Tulasu ore cluster, western Tianshan, Xinjiang, China

    Zhao, Xiaobo; Xue, Chunji; Symons, David T. A.; Zhang, Zhaochong; Wang, Honggang


    The successful exploration for porphyry copper deposit in western Tianshan, Xinjiang, faces great challenge. Tulasu basin is an important epithermal gold ore cluster in western Tianshan, which was formed in a southwest-Pacific-type island-arc setting during the late Paleozoic by the southward subduction of the North Tianshan ocean beneath the Yili plate. Porphyry Cu-Au deposits are possibly to be found at depth or adjacent to these epithermal gold deposits. Some sulfide-mineralized microgranular enclaves of monzonite porphyry and microdiorite were found in andesites of the Tawuerbieke gold district, Tulasu basin. The enclaves are randomly distributed, with generally round or subangular shape and commonly clearly defined within their host andesite, and have a chilled surrounding margin of andesite. The monzonite porphyry enclaves (MPE) exhibit porphyritic texture with the phenocrysts of plagioclase and K-feldspar. The microdiorite enclaves (MDE) are mainly composed of plagioclase and hornblende with an aplitic texture and massive structure. The host andesites show porphyritic texture, with the phenocrysts major of plagioclase, minor of hornblende and clinopyroxene. The groundmass consists of short-column plagioclase and minor clinopyroxene with a hyalopilitic texture. Zircon grains from a MPE sample yield a weighted 206Pb/238U age of 356.2 ± 4.3 Ma (n = 13, MSWD = 1.11), which is effectively coincident with the 360.5 ± 3.4 Ma (n = 20, MSWD = 0.61) of an andesite sample within analytical error, indicating that they were coeval. In addition, the MPE, MDE and the andesite samples share similar normalized incompatible element and rare earth element patterns that are characterized by a pronounced enrichment of large ion lithophile elements and a deficit of high field strength elements. Moreover, the samples show similar Nd isotope compositions to the contemporary andesites and basaltic andesites. Detailed petrology, geochronology and geochemistry studies suggest that

  4. Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru

    Chauvet, Alain; Bailly, Laurent; André, Anne-Sylvie; Monié, Patrick; Cassard, Daniel; Tajada, Fernando Llosa; Vargas, Juan Rosas; Tuduri, Johann


    The epithermal Shila-Paula Au-Ag district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main E-W vein with secondary N55-60°W veins—two directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have been guided by regional N40°E and N40°W fractures. Two main vein-filling stages are identified. stage 1 is a quartz-adularia-pyrite-galena-sphalerite-chalcopyrite-electrum-Mn silicate-carbonate assemblage that fills the main E-W veins. stage 2, which contains most of the precious-metal mineralization, is divided into pre-bonanza and bonanza substages. The pre-bonanza substage consists of a quartz-adularia-carbonate assemblage that is observed within the secondary N45-60°W veins, in veinlets that cut the stage 1 assemblage, and in final open-space fillings. The two latter structures are finally filled by the bonanza substage characterized by a Fe-poor sphalerite-chalcopyrite-pyrite-galena-tennantite-tetrahedrite-polybasite-pearceite-electrum assemblage. The ore in the main veins is systematically brecciated, whereas the ore in the secondary veins and geodes is characteristic of open-space crystallization. Microthermometric measurements on sphalerite from both stages and on quartz and calcite from stage 2 indicate a salinity range of 0 to 15.5 wt% NaCl equivalent and homogenization temperatures bracketed between 200 and 330°C. Secondary CO2-, N2- and H2S-bearing fluid inclusions are also identified. The age of vein emplacement, based on 40Ar/39Ar ages obtained on adularia of different veins, is estimated at around 11 Ma, with some overlap between adularia of stage 1 (11.4±0.4 Ma) and of stage 2 (10.8±0.3 Ma). A three-phase tectonic model has been constructed to explain the

  5. Mesozoic Large-scale Mineralization and Multiple Lithospheric Extensions in South China


    South China is the most important polymetallic (tungsten, tin, bismuth, copper, silver,antimony, mercury, rare metals, heavy rare earth elements, gold and lead-zinc) province in China. This paper describes the basic characteristics of Mesozoic large-scale mineralization in South China. The large-scale mineralization mainly took place in three intervals: 170-150 Ma, 140-126 Ma and 110-80Ma. Among these the first stage is mainly marked by copper, lead-zinc and tungsten mineralization and the third stage is mainly characterized by tin, gold, silver and uranium mineralization. The stage of 140-126 Ma mainly characterized by tungsten and tin mineralization is a transitional interval from the first to the third stage. In light of the current research results of the regional tectonic evolution it is proposed that the large-scale mineralization in the three stages is related to post-collision between the South China block and the North China block, transfer of the principal stress-field of tectonic regimes from N-S to E-W direction, and multiple back-arc lithospheric extensions caused by subduction of the Paleo-Pacific plate.

  6. Design of a high-flux epithermal neutron beam using 235U fission plates at the Brookhaven Medical Research Reactor.

    Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P


    Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed.

  7. Time-of-flight calibration of a 6Li glass epithermal neutron detector

    Livingston; Saleh; Block; Brand


    The curing of Portland cement concrete involves the conversion of water from a free to a bound state. The process can be monitored nondestructively by measuring the shift in the neutron energy spectrum in the epithermal range (0.025-1 eV). A tuned array of 6Li glass detectors has been constructed with varying efficiencies over the epithermal energy range. To determine the efficiency of each detector as a function of neutron energy, it is necessary to calibrate it against a reference neutron spectrum. This was accomplished using a time-of-flight approach with a pulsed neutron beam produced at the Gaerttner LINAC Laboratory at Rensselaer Polytechnic Institute. With a neutron flight path of 25 m it was possible to determine the neutron detector efficiencies to an energy resolution of 11 microeV. The data showed good agreement with the detector design calculations.

  8. Evaluation of an iron-filtered epithermal neutron beam for neutron-capture therapy.

    Musolino, S V; McGinley, P H; Greenwood, R C; Kliauga, P; Fairchild, R G


    An epithermal neutron filter using iron, aluminum, and sulfur was evaluated to determine if the therapeutic performance could be improved with respect to aluminum-sulfur-based filters. An empirically optimized filter was developed that delivered a 93% pure beam of 24-keV epithermal neutrons. It was expected that a thick filter using iron with a density thickness greater than 200 g/cm2 would eliminate the excess gamma contamination found in Al-S filters. This research showed that prompt gamma production from neutron interactions in iron was the dominant dose component. Dosimetric parameters of the beam were determined from the measurement of absorbed dose in air, thermal neutron flux in a head phantom, neutron and gamma spectroscopy, and microdosimetry.

  9. Optimization of an accelerator-based epithermal neutron source for neutron capture therapy

    Kononov, O.E.; Kononov, V.N.; Bokhovko, M.V.; Korobeynikov, V.V.; Soloviev, A.N.; Chu, W.T.


    A modeling investigation was performed to choose moderator material and size for creating optimal epithermal neutron beams for BNCT based on a proton accelerator and the 7Li(p,n)7Be reaction as a neutrons source. An optimal configuration is suggested for the beam shaping assembly made from polytetrafluoroethylene and magnesium fluorine. Results of calculation were experimentally tested and are in good agreement with measurements.

  10. Can epithermal boron neutron capture therapy treat primary and metastatic liver cancer?

    Wallace, S.A. [Austin Repatriation Medical Centre, Heidelberg (Australia); Carolan, M.C. [Illawarra Cancer Care Centre, Wollongong (Australia); Allen, B.J. [St George Cancer Care Centre, Kogarah (Australia)


    Full text: The poor prognosis of metastatic cancer to the liver calls for the investigation of alternative treatment modalities. This paper analyses the possible use of epithermal boron neutron capture therapy for the palliative treatment of these cancers. We examine possible treatment planning scenarios for selected tumour to liver boron ratios, and specifically for the epithermal beam at the HFR, Petten. It is required that a therapeutic ratio> 1 be achieved over the entire organ. Monte Carlo calculations were performed using the radiation transport code MCNP. The geometrical model used a `variable voxel` technique to reconstruct an anthropomorphic phantom from CT scans. Regions of interest such as the liver were modelled to a resolution of a few millimetres, whereas surrounding regions were modelled with lesser detail thereby facilitating faster computation time. Three dimensional dose distributions were calculated for a frontal beam directed at the liver, and found to be in satisfactory agreement with measurements using bare and cadmium covered gold foils, PIN and MOSFET dosimeters for fast neutron and gamma measurements respectively. Dose distributions were calculated for orthogonal epithermal neutron beams to the front and side, using the parameters of the epithermal beam at Petten, and assumed tumour and normal tissue boron-10 concentrations of 30 ppm and 7.5 ppm boron-10 respectively. The therapeutic ratio (i e the dose to the tumour relative to the maximum dose to normal tissue) was found to be about 1.8, reducing to unity for the limiting condition of a tumour in the posterior liver. This result opens up the possibility of palliative therapy for the management of primary and metastatic liver cancer.

  11. Facility for parity and time reversal experiments with intense epithermal (eV) neutron beams

    Bowman, C. D.; Bowman, J. D.; Herczeg, P.; Szymanski, J.; Yuan, V. W.; Anaya, J. M.; Mortensen, R.; Postma, H.; Delheij, P. P. J.; Baker, O. K.; Gould, C. R.; Haase, D. G.; Mitchell, G. E.; Roberson, N. R.; Zhu, X.; McDonald, A. B.; Benton, D.; Tippens, B.; Chupp, T. E.


    A facility for polarized epithermal neutrons of high intensity is set up at the Los Alamos National Laboratory for parityviolation and time reversal experiments at neutron resonances over a wide range of neutron energies. The beam is polarized with the aid of a polarized proton target used as a neutronspin filter. Total cross section measurements as well as capture gamma-ray experiments will be carried out. The main features of this system will be discussed.

  12. Performance characteristics of the MIT fission converter based epithermal neutron beam.

    Riley, K J; Binns, P J; Harling, O K


    A pre-clinical characterization of the first fission converter based epithermal neutron beam (FCB) designed for boron neutron capture therapy (BNCT) has been performed. Calculated design parameters describing the physical performance of the aluminium and Teflon filtered beam were confirmed from neutron fluence and absorbed dose rate measurements performed with activation foils and paired ionization chambers. The facility currently provides an epithermal neutron flux of 4.6 x 10(9) n cm(-2) s(-1) in-air at the patient position that makes it the most intense BNCT source in the world. This epithermal neutron flux is accompanied by very low specific photon and fast neutron absorbed doses of 3.5 +/- 0.5 and 1.4 +/- 0.2 x 10(-13) Gy cm2, respectively. A therapeutic dose rate of 1.7 RBE Gy min(-1) is achievable at the advantage depth of 97 mm when boronated phenylalanine (BPA) is used as the delivery agent, giving an average therapeutic ratio of 5.7. In clinical trials of normal tissue tolerance when using the FCB, the effective prescribed dose is due principally to neutron interactions with the nonselectively absorbed BPA present in brain. If an advanced compound is considered, the dose to brain would instead be predominately from the photon kerma induced by thermal neutron capture in hydrogen and advantage parameters of 0.88 Gy min(-1), 121 mm and 10.8 would be realized for the therapeutic dose rate, advantage depth and therapeutic ratio, respectively. This study confirms the success of a new approach to producing a high intensity, high purity epithermal neutron source that attains near optimal physical performance and which is well suited to exploit the next generation of boron delivery agents.

  13. Shielding and beam performance of the new epithermal neutron irradiation facility at the MITR-II

    Riley, K.J.; Binns, P.J.; Ledesma, M.N.; Sutharshan, B.; Harling, O.K. [Nuclear Reactor Laboratory, MIT, Cambridge, MA (United States)


    A new epithermal neutron beam for NCT research has been constructed at the MIT Research Reactor. The computer code MCNP was used extensively in the neutronic design of the beamline and shielding for the treatment room. The calculated design parameters compare well with those obtained from a series of measurements performed to assess ambient radiation levels and in-beam performance at the facility. (author)

  14. Epithermal neutron formation for boron neutron capture therapy by adiabatic resonance crossing concept

    Khorshidi, A.; Ghafoori-Fard, H.; Sadeghi, M.


    Low-energy protons from the cyclotron in the range of 15-30 MeV and low current have been simulated on beryllium (Be) target with a lead moderator around the target. This research was accomplished to design an epithermal neutron beam for Boron Neutron Capture Therapy (BNCT) using the moderated neutron on the average produced from 9Be target via (p, xn) reaction in Adiabatic Resonance Crossing (ARC) concept. Generation of neutron to proton ratio, energy distribution, flux and dose components in head phantom have been simulated by MCNP5 code. The reflector and collimator were designed in prevention and collimation of derivation neutrons from proton bombarding. The scalp-skull-brain phantom consisting of bone and brain equivalent material has been simulated in order to evaluate the dosimetric effect on the brain. Results of this analysis demonstrated while the proton energy decreased, the dose factor altered according to filters thickness. The maximum epithermal flux revealed using fluental, Fe and bismuth (Bi) filters with thicknesses of 9.4, 3 and 2 cm, respectively and also the epithermal to thermal neutron flux ratio was 103.85. The potential of the ARC method to replace or complement the current reactor-based supply sources of BNCT purposes.

  15. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    Mitchell, H.E.


    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 10{sup 7} neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF{sub 3} composite and a stacked Al/Teflon design) at various incident electron energies.

  16. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    Mitchell, Hannah E. [Georgia Inst. of Technology, Atlanta, GA (United States)


    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 107 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF3 composite and a stacked Al/Teflon design) at various incident electron energies.

  17. Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming

    Day, Warren C.; Frost, Thomas P.; Hammarstrom, Jane M.; Zientek, Michael L.


    Scientific Investigations Report 2016–5089 and accompanying data releases are the products of the U.S. Geological Survey (USGS) Sagebrush Mineral-Resource Assessment (SaMiRA). The assessment was done at the request of the Bureau of Land Management (BLM) to evaluate the mineral-resource potential of some 10 million acres of Federal and adjacent lands in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming. The need for this assessment arose from the decision by the Secretary of the Interior to pursue the protection of large tracts of contiguous habitat for the greater sage-grouse (Centrocercus urophasianus) in the Western United States. One component of the Department of the Interior plan to protect the habitat areas includes withdrawing selected lands from future exploration and development of mineral and energy resources, including copper, gold, silver, rare earth elements, and other commodities used in the U.S. economy. The assessment evaluates the potential for locatable minerals such as gold, copper, and lithium and describes the nature and occurrence of leaseable and salable minerals for seven Sagebrush Focal Areas and additional lands in Nevada (“Nevada additions”) delineated by BLM. Supporting data are available in a series of USGS data releases describing mineral occurrences (the USGS Mineral Deposit Database or “USMIN”), oil and gas production and well status, previous mineral-resource assessments that covered parts of the areas studied, and a compilation of mineral-use cases based on data provided by BLM, as well as results of the locatable mineral-resource assessment in a geographic information system. The present assessment of mineral-resource potential will contribute to a better understanding of the economic and environmental trade-offs that would result from closing approximately 10 million acres of Federal lands to mineral entry.

  18. Synchrotron radiation X-ray fluorescence analysis on altered mineral muscovite in gold deposit

    TANG Yun-Hui; YUAN Wan-Ming; WANG Li-Hua; HAN Chun-Ming; HUANG Yu-Ying; HE Wei


    Synchrotron radiation X-ray fluorescence (SRXRF) microprobe was used to ananlyse altered mineral muscovite and its surrounding feldspar in Yuerya gold deposit. The major, minor and trace elements of the two minerals were detected and analyzed. SRXRF analysis showed that the Yuerya muscovite had a complex chemical composition, containing K, Fe, Ca, Ti, Cr, Mn, Co, Cu, Zn and many trace or ultra-trace elements. Since muscovite resulted from the alteration of hydrothermal ore fluid acting on feldspar (plagioclase), the difference of chemical composition between the two minerals shows the components of ore fluid, which are characterized by the enrichment of alkaline and alkaline-earth metal elements K, Ca and ore-associated elements Fe, Cu, Zn. And gold, silver and platinum, invisible under microscope, were detected in some areas of muscovite, but not found in feldspar. Especially platinum, a mantle material, is rarely seen in the earth crust but now found in the gold deposit of magmatic sources; its appearance approves the idea of mantle flux participating in the gold mineralization, which suggests that the tectonic event controlling gold mineralization in the Yuerya district is a mantle phenomenon.

  19. Tetrahedrite-Group Minerals in the Jinjitai Gold Deposit, Western Sichuan


    There are quite a few tetrahedrite-group minerals in the Jinjitai gold deposit, western Sichuan, which occur in an interstratified fractured zone of Middle Devonian carbonate rock series. The gold ore consists of pyrite, chalcopyrite, tetrahedrite-group minerals, galena, sphalerite and gold-silver series minerals, with an element association of Au-Cu-Ag-Pb-As-Sb-Bi. Electron microprobe analyses of the tetrahedrite-group minerals gave the following results: copper 40.04 to 42.27% (average 40.04%), iron 1.24 to 7.78% (average 4.13%), zinc 0.39 to 7.06% (average 3.58%), arsenic 5.41 to 17.40% (average 8.84%), antimony 2.70 to 20.46% (average 15.87%), and silver 0.02 to 0.73% (average 0.28%). The mineral varieties include zinc-antimony-tetrahedrite, iron-antimony-tetrahedrite, iron-tennatite and zincotennatite. These data show that there is a complete isomorphous series between Sb and As. From above downwards tetrahedrite varies from zinc- and antimony-rich to iron- and arsenic-rich compositions. Their occurrence and zonal features are very important for exploration of the same type of gold deposits in western Sichuan.

  20. 微波马弗炉处理—火焰原子吸收光谱法测定废旧电路板中金银铂钯%Determination of gold, silver, platinum, palladium in waste circuit boards samples by flame atomic absorption spectrometry with microwave muffle furnace pretreatment

    叶艳青; 羊波; 杨新周; 李银科; 胡秋芬


    A novel method for the determination of gold, silver, platinum and palladium in waste circuit board samples was investigated in this paper by flame atomic absorption spectrometry with microwave muffle furnace pretreatment. 5. 0 g of crashed waste circuit board samples was weighed and burned in microwave muffle furnace at 550 ℃ for 30 min to decompose organic matter. After the burning things were dissolved with aqua regia, gold, silver, platinum and palladium in the sample solution were determined by flame atomic absorption spectrometry. The detection limit of gold, silver, platinum and palladium was 0. 078, 0. 12, 0. 15 and 0. 15 mg/mL, respectively. The recoveries were between 90% and 108%. The method was applied to the same waste circuit board sample for 7 times. The relative standard deviations on the same day were between 2. 2% and 2. 9%, and the relative standard deviations on different day between 3,3% and 3. 5%. The method was applied to the analysis of waste circuit board and the results were consistent with those obtained by microwave digestion inductively coupled plasma atomic emission spectrometry.%研究了微波马弗炉加热处理样品,火焰原子吸收光谱法测定废旧电路板中金、银、铂、钯的方法.称取5.0g粉碎后废旧电路板样品,用微波马弗炉在550℃灼烧30 min分解有机物,用王水溶解样品,样品溶液中的金、银、铂、钯用火焰原子吸收光谱法进行测定.金、银、铂、钯的方法检出限分别为0.078、0.12、0.15和0.15 mg/mL;方法回收率在90%~108%之间;用本方法平行测定同一废旧电路板样品7次,日内相对标准偏差为2.2%~2.9%;日间相对标准偏差为3.3%~3.5%.将本方法用于废旧电路板分析,测得结果与微波消解—电感耦合等离子体发射光谱法一致.

  1. Precious metaltellurides and other Te-bearing minerals in different paragenesis of Argentina: A review

    Milka K de Brodtkorb


    Full Text Available Severalpolymetallic deposits containing tellurides and Te-bearing minerals occur indifferent geologic terrains of Argentina. Tellurides with Ag and /or Au arewidespread in meso and epithermal environments; they are structurallycontrolled and genetically related to Jurassic or Miocene-Pliocene volcanism.These species are represented by calaverite, hessite, stützite, krennerite,sylvanite, petzite and cervellite. Other Te-bearing minerals are present notonly in epithermal deposits but also in different assemblages such asintraplutonic W deposits, skarn and mafic-ultramafic bodies. They are Te,altaite, nagyágite, melonite- merenskyite, tetradymite, telurobismuthite,kawazulite, Te-canfieldite and goldfieldite. Paragenesis of the differentdeposits and chemical data of the minerals are given.

  2. Late Cretaceous porphyry Cu and epithermal Cu-Au association in the Southern Panagyurishte District, Bulgaria: the paired Vlaykov Vruh and Elshitsa deposits

    Kouzmanov, Kalin; Moritz, Robert; von Quadt, Albrecht; Chiaradia, Massimo; Peytcheva, Irena; Fontignie, Denis; Ramboz, Claire; Bogdanov, Kamen


    Vlaykov Vruh-Elshitsa represents the best example of paired porphyry Cu and epithermal Cu-Au deposits within the Late Cretaceous Apuseni-Banat-Timok-Srednogorie magmatic and metallogenic belt of Eastern Europe. The two deposits are part of the NW trending Panagyurishte magmato-tectonic corridor of central Bulgaria. The deposits were formed along the SW flank of the Elshitsa volcano-intrusive complex and are spatially associated with N110-120-trending hypabyssal and subvolcanic bodies of granodioritic composition. At Elshitsa, more than ten lenticular to columnar massive ore bodies are discordant with respect to the host rock and are structurally controlled. A particular feature of the mineralization is the overprinting of an early stage high-sulfidation mineral assemblage (pyrite ± enargite ± covellite ± goldfieldite) by an intermediate-sulfidation paragenesis with a characteristic Cu-Bi-Te-Pb-Zn signature forming the main economic parts of the ore bodies. The two stages of mineralization produced two compositionally different types of ores—massive pyrite and copper-pyrite bodies. Vlaykov Vruh shares features with typical porphyry Cu systems. Their common geological and structural setting, ore-forming processes, and paragenesis, as well as the observed alteration and geochemical lateral and vertical zonation, allow us to interpret the Elshitsa and Vlaykov Vruh deposits as the deep part of a high-sulfidation epithermal system and its spatially and genetically related porphyry Cu counterpart, respectively. The magmatic-hydrothermal system at Vlaykov Vruh-Elshitsa produced much smaller deposits than similar complexes in the northern part of the Panagyurishte district (Chelopech, Elatsite, Assarel). Magma chemistry and isotopic signature are some of the main differences between the northern and southern parts of the district. Major and trace element geochemistry of the Elshitsa magmatic complex are indicative for the medium- to high-K calc-alkaline character of

  3. Lunar prospector epithermal neutrons from impact craters and landing sites: Implications for surface maturity and hydrogen distribution

    Johnson, J. R.; Feldman, W.C.; Lawrence, D.J.; Maurice, S.; Swindle, T.D.; Lucey, P.G.


    Initial studies of neutron spectrometer data returned by Lunar Prospector concentrated on the discovery of enhanced hydrogen abundances near both lunar poles. However, the nonpolar data exhibit intriguing patterns that appear spatially correlated with surface features such as young impact craters (e.g., Tycho). Such immature crater materials may have low hydrogen contents because of their relative lack of exposure to solar wind-implanted volatiles. We tested this hypothesis by comparing epithermal* neutron counts (i.e., epithermal -0.057 ?? thermal neutrons) for Copernican-age craters classified as relatively young, intermediate, and old (as determined by previous studies of Clementine optical maturity variations). The epithermal* counts of the crater and continuous ejecta regions suggest that the youngest impact materials are relatively devoid of hydrogen in the upper 1 m of regolith. We also show that the mean hydrogen contents measured in Apollo and Luna landing site samples are only moderately well correlated to the epithermal* neutron counts at the landing sites, likely owing to the effects of rare earth elements. These results suggest that further work is required to define better how hydrogen distribution can be revealed by epithermal neutrons in order to understand more fully the nature and sources (e.g., solar wind, meteorite impacts) of volatiles in the lunar regolith.

  4. Designing an epithermal neutron beam for boron neutron capture therapy for a DIDO type reactor using MCNP

    Ross, D.; Constantine, G.; Weaver, D. R.; Beynon, T. D.


    This paper describes work undertaken to design an epithermal neutron beam for a DIDO type reactor for use in boron neutron capture therapy, a form of cancer treatment. It involved extensive use of MCNP, a Monte Carlo computer code. Initially, calculations were made with MCNP to simulate earlier experiments with an epithermal beam on the DIDO reactor. This comparison made it possible both to validate the Monte Carlo modelling of the reactor and to gain an insight into the important features of the simulation. Following this, MCNP was used to design a filtered epithermal neutron beam facility for DIDO's largest beam tube, a 13.7 cm radius horizontal tube which extends radially away from the core. First a selection was made of the optimum filter components for the beam. Then the research concentrated on combining these filter elements to construct a practical epithermal beam design. The results suggest that the optimum method of generating the epithermal neutron source is to employ a filter combination consisting principally of liquid argon with the addition of cadmium, aluminium, titanium and possibly tin. The calculations also show that the resultant neutron beam would have a flux greater than 1.0 × 10 9 n cm -2 s -1 and have sufficiently low fast-neutron and gamma-ray contamination.

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

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


    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.

  6. Epithermal neutron beam adoption for liver cancer treatment by boron and gadolinium neutron capture therapy

    Matsumoto, Tetsuo [Musashi Inst. of Tech., Kawasaki, Kanagawa (Japan). Atomic Energy Research Lab


    Comparative evaluation was made on depth-dose distribution in boron neutron capture therapy (B-NCT) and gadolinium one (Gd-NCT) for the treatments of liver cancers. At present, epithermal neutron beam is expected to be applicable to the treatment of deep and widespread tumors. ICRU computational model of ADAM and EVA was used as a liver phantom loading a tumor at depth of 6 cm in its central region. Epithermal neutron beam of Musashi reactor was used as the primary neutron beam for the depth-dose calculation. Calculation was conducted using the three-dimensional continuous-energy Monte Carlo code MCNP4A. The doses observed in both NCTs were bumped over the tumor region but the dose for Gd-NCT was not so tumor-specific compared with that for BNCT because radiation in Gd-NCT was due to {gamma}-ray. The mean physical dose was 4 Gy/h for boron 30 ppm and 5 Gy/h for Gd 1000 ppm when exposed to an epithermal neutron flux of 5x10{sup 8} n/cm{sup -2}/sec and the dose ratio of tumor-to normal tissue was 2.7 for boron and 2.5 for Gd. The lethal dose of 50 Gy for the liver can be accomplished under conditions where the dose has not reached 25 Gy, the tolerance dose of the normal tissue. This seems very encouraging and indicating that both B-NCT and Gd-NCT are applicable for the treatment for liver cancer. However, if normal tissue contain 1/4 of the tumor concentration of boron or Gd, the BNCT would still possible when considering a large RBE value for {sup 10}B(n, {alpha}) reaction but the Gd-NCT would impossible for deep liver treatment. (M.N.)

  7. Neutron kinetics in moderators and SNM detection through epithermal-neutron-induced fissions

    Gozani, Tsahi; King, Michael J.


    Extension of the well-established Differential Die Away Analysis (DDAA) into a faster time domain, where more penetrating epithermal neutrons induce fissions, is proposed and demonstrated via simulations and experiments. In the proposed method the fissions stimulated by thermal, epithermal and even higher-energy neutrons are measured after injection of a narrow pulse of high-energy 14 MeV (d,T) or 2.5 MeV (d,D) source neutrons, appropriately moderated. The ability to measure these fissions stems from the inherent correlation of neutron energy and time ("E-T" correlation) during the process of slowing down of high-energy source neutrons in common moderating materials such as hydrogenous compounds (e.g., polyethylene), heavy water, beryllium and graphite. The kinetic behavior following injection of a delta-function-shaped pulse (in time) of 14 MeV neutrons into such moderators is studied employing MCNPX simulations and, when applicable, some simple "one-group" models. These calculations served as a guide for the design of a source moderator which was used in experiments. Qualitative relationships between slowing-down time after the pulse and the prevailing neutron energy are discussed. A laboratory system consisting of a 14 MeV neutron generator, a polyethylene-reflected Be moderator, a liquid scintillator with pulse-shape discrimination (PSD) and a two-parameter E-T data acquisition system was set up to measure prompt neutron and delayed gamma-ray fission signatures in a 19.5% enriched LEU sample. The measured time behavior of thermal and epithermal neutron fission signals agreed well with the detailed simulations. The laboratory system can readily be redesigned and deployed as a mobile inspection system for SNM in, e.g., cars and vans. A strong pulsed neutron generator with narrow pulse (<75 ns) at a reasonably high pulse frequency could make the high-energy neutron induced fission modality a realizable SNM detection technique.

  8. Neutron kinetics in moderators and SNM detection through epithermal-neutron-induced fissions

    Gozani, Tsahi, E-mail: [1050 Harriet St., Palo Alto, CA 94301 (United States); King, Michael J. [Rapiscan Laboratories Inc., 520 Almanor Ave., Sunnyvale, CA 94085 (United States)


    Extension of the well-established Differential Die Away Analysis (DDAA) into a faster time domain, where more penetrating epithermal neutrons induce fissions, is proposed and demonstrated via simulations and experiments. In the proposed method the fissions stimulated by thermal, epithermal and even higher-energy neutrons are measured after injection of a narrow pulse of high-energy 14 MeV (d,T) or 2.5 MeV (d,D) source neutrons, appropriately moderated. The ability to measure these fissions stems from the inherent correlation of neutron energy and time (“E–T” correlation) during the process of slowing down of high-energy source neutrons in common moderating materials such as hydrogenous compounds (e.g., polyethylene), heavy water, beryllium and graphite. The kinetic behavior following injection of a delta-function-shaped pulse (in time) of 14 MeV neutrons into such moderators is studied employing MCNPX simulations and, when applicable, some simple “one-group” models. These calculations served as a guide for the design of a source moderator which was used in experiments. Qualitative relationships between slowing-down time after the pulse and the prevailing neutron energy are discussed. A laboratory system consisting of a 14 MeV neutron generator, a polyethylene-reflected Be moderator, a liquid scintillator with pulse-shape discrimination (PSD) and a two-parameter E–T data acquisition system was set up to measure prompt neutron and delayed gamma-ray fission signatures in a 19.5% enriched LEU sample. The measured time behavior of thermal and epithermal neutron fission signals agreed well with the detailed simulations. The laboratory system can readily be redesigned and deployed as a mobile inspection system for SNM in, e.g., cars and vans. A strong pulsed neutron generator with narrow pulse (<75 ns) at a reasonably high pulse frequency could make the high-energy neutron induced fission modality a realizable SNM detection technique.

  9. Epithermal neutron beam for BNCT research at the Washington State University TRIGA research reactor

    Nigg, D.W.; Venhuizen, J.R.; Wheeler, F.J.; Wemple, C.A. [Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID (United States); Tripard, G.E.; Gavin, P.R. [Washington State University, Pullman, WA (United States)


    A new epithermal-neutron beam facility for BNCT (Boron Neutron Capture Therapy) research and boronated agent screening in animal models is in the final stages of construction at Washington State University (WSU). A key distinguishing feature of the design is the incorporation of a new, high-efficiency, neutron moderating and filtering material, Fluental, developed by the Technical Research Centre of Finland. An additional key feature is the provision for adjustable filter-moderator thickness to systematically explore the radiobiological consequences of increasing the fast-neutron contamination above the nominal value associated with the baseline system. (author)

  10. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    Kosunen, A


    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?){sup water} {sub air}, in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in {sup 60}Co gamma beams. In photon beam dosimetry (S I ?){sup water} {sub air} can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation

  11. Filter/moderator system for a BNCT beam of epithermal neutrons at nuclear reactor MARIA

    Tyminska, Katarzyna


    Boron Neutron Capture Therapy is a very promising form of cancer therapy, consisting in irradiating a stable isotope of boron (10B) concentrated in tumor cells with a low energy neutron beam. This technique makes it possible to destroy tumor cells, leaving healthy tissues practically unaffected. In order to carry out the therapy in the proper way, the proper range of the neutron beam energy has to be chosen. In this paper we present a filter/moderator system modeled with MCNP code in order to obtain an epithermal neutron beam for BNCT post at MARIA reactor in Swierk.

  12. Comparison of neutron spectrum measurement methods used for the epithermal beam of the LVR-15 research reactor.

    Viererbl, L; Klupák, V; Lahodová, Z; Marek, M


    The LVR-15 research reactor's horizontal channel with its epithermal neutron beam is used mainly for boron neutron capture therapy. Neutrons from the reactor core pass through a special filter before the collimator and the beam outlet. Neutron fluence and spectrum are the basic characteristics of an epithermal neutron beam. Three methods used to measure the beam's neutron spectrum are described: the activation method, a Bonner sphere spectrometer with gold activation detectors and a Bonner sphere spectrometer with LiI(Eu) scintillation detector. Examples of results are compared and discussed.

  13. A new monitor for routine thermal and epithermal neutron fluence rate monitoring in k{sub 0} INAA

    Koster-Ammerlaan, M.J.J. [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629JB Delft (Netherlands)], E-mail:; Bacchi, M.A. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo 13400-970, Piracicaba (Brazil); Bode, P. [Delft University of Technology, Reactor Institute Delft, Mekelweg 15, 2629JB Delft (Netherlands); Nadai Fernandes, E.A. de [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo 13400-970, Piracicaba (Brazil)


    The Zr-Au set for monitoring the thermal and epithermal neutron fluence rate and the epithermal spectrum parameter {alpha} is not always practicable for routine application of INAA in well-thermalized facilities. An alternative set consisting of Cr, Au and Mo provides values for the thermal neutron fluence rate, f and {alpha} that are not significantly different from those found via the Zr-Au method and the Cd-covered Zr-method. The IRMM standard SMELS-II was analyzed using the (Au-Cr-Mo) monitor and a good agreement was obtained.

  14. Timing and origin of ignimbrites exposed in the Palmarejo and Guazapares mining districts in western Chihuahua: Implications for the genesis of Ag-Au epithermal deposits

    Mahar, M. A.; Ramirez, A.; Goodell, P.


    In the present work, we provided the zircon U-Pb ages and Hf isotope composition of the post-Laramidic ignimbrites exposed in the Palmarejo and Guazapares Ag-Au epithermal mineralization districts in western Chihuahua, Mexico. Three ignimbrite samples from Guerra Al Tirano and one sample from Guadalupe Norte dome in the Palmarejo district yielded weighted mean ages of 23.1 ± 0.4 Ma, 23.4 ± 0.4 Ma, 23.7 ± 0.4 Ma and 23.7 ± 1.1 Ma, respectively. One sample from San Francisco in the Guazapares district yielded a weighted mean age of 28 ± 1.0 Ma. Zircon U-Pb ages suggest that the post-subduction ignimbrite flare-up in the Palmarejo and Guazapares district remained restricted in the Early Oligocene to Early Miocene. The Hf isotope composition of the selected grains is dominantly positive with the majority (85%) of the analyses ranging from +1.0 to +5.8. Three samples from Guerra Al Tirano and one sample from San Francisco yielded radiogenic and positive weighted mean ɛHf (t) of 4.6 ± 1.0, 3.3 ± 0.8, and 4.7 ± 0.9 and 1.6 ± 0.9, respectively. The Hf isotope composition observed in the post-Laramidic ignimbrites is identical to the Late-Cretaceous Early Tertiary granodiorites exposed 60 km southeast in the Rio El Fuerte region. However, we did not find any inheritance from the Laramidic plutons. It is possible that the older zircons have dissolved by the strong acidic fluids (pH <4), that is typical for the high sulfidation epithermal mineralization. Newly grown inheritance-free zircons actually recorded the timing of achieving the near-surface relatively lower sulfidation conditions, where acidic fluids have been neutralized while interacting with meteoric waters. Alternatively, the absence of zircon inheritance and dominant positive Hf isotope composition suggest a minimum role of crustal-derived melts in the generation of the ignimbrites during Early Oligocene to Early Miocene. We suggest that the ignimbrites recorded the dominant contribution from mantle

  15. The Chahnaly low sulfidation epithermal gold deposit, western Makran volcanic arc, southeastern Iran

    Sholeh, Ali; Rastad, Ebrahim; Huston, David L.; Gemmell, J. Bruce; Taylor, Ryan D.


    The Chahnaly low-sulfidation epithermal Au deposit and nearby Au prospects are located northwest of the intermittently active Bazman stratovolcano on the western end of the Makran volcanic arc, which formed as the result of subduction of the remnant Neo-Tethyan oceanic crust beneath the Lut block. The arc hosts the Siah Jangal epithermal and Kharestan porphyry prospects, near Taftan volcano, as well as the Saindak Cu-Au porphyry deposit and world-class Reko Diq Cu-Au porphyry deposit, near Koh-i-Sultan volcano to the east-northeast in Pakistan. The host rocks for the Chahnaly deposit include early Miocene andesite and andesitic volcaniclastic rocks that are intruded by younger dacitic domes. Unaltered late Miocene dacitic ignimbrites overlie these rocks. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon geochronology data yield ages between 21.8 and 9.9 Ma for the acidic-intermediate regional volcanism. The most recent volcanic activity of the Bazman stratovolcano involved extrusion of an olivine basalt during Pliocene to Quaternary times. Interpretation of geochemical data indicate that the volcanic rocks are synsubduction and calc-alkaline to subalkaline. The lack of a significant negative Eu anomaly, a listric-shaped rare earth element pattern, and moderate La/Yb ratios of host suites indicate a high water content of the source magma.

  16. The dose comparison between the THOR and HFR epithermal neutron beams

    Lin, Yi-Chun [Biomedical Engineering and Environmental Sciences Department, National Tsing Hua University, Hsinchu, Taiwan (China); Roca, Antoaneta [Institute for Energy, Joint Research Centre, European Commission (Netherlands); Faculty of Physics, University of Bucharest, Bucuresti-Magurele (Romania); Liu, Yuan-Hao, E-mail: [Health Physics Division, Nuclear Science and Technology Development Center, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Tsai, Pi-En [Health Physics Division, Nuclear Science and Technology Development Center, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Nievaart, Sander [Institute for Energy, Joint Research Centre, European Commission (Netherlands); Liu, Hong-Ming [Health Physics Division, Nuclear Science and Technology Development Center, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Moss, Ray [Institute for Energy, Joint Research Centre, European Commission (Netherlands); Chou, Wen-Tsae [Biomedical Engineering and Environmental Sciences Department, National Tsing Hua University, Hsinchu, Taiwan (China); Jiang, Shiang-Huei [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan (China)


    This study is a part of the beam comparison campaign, inter-center dose comparison, between boron neutron capture therapy facilities at the Tsing Hua Open-pool Reactor and the High Flux Reactor. The clinical information exchange can improve the dosimetry uncertainty for medical physics in a mixed field. The method of paired Mg(Ar) and TE(TE) ionization chambers was used to determine the gamma-ray and neutron dose rates. Furthermore, activation foils, including gold, copper, and manganese, were employed to estimate the thermal and epithermal neutron fluxes. Measurements were performed free in air and also in a PMMA phantom. All the chambers were calibrated using a {sup 60}Co primary standard source at the Institute of Nuclear Energy Research, Taiwan. Spectrum dependent neutron sensitivity of TE(TE) chamber is one of the important parameters to evaluate dose components. The requested neutron spectra were calculated by the Monte Carlo code MCNP. The measured thermal neutron fluxes, gamma-ray and neutron dose rates of the THOR beam in the phantom were 2.6, 2.2, and 2.1 times of the HFR beam at 2.5-cm depth, respectively. The higher thermal neutron flux and neutron and gamma-ray dose rates are due to the higher epithermal neutron beam intensity of the THOR.

  17. Dose monitoring for boron neutron capture therapy using a reactor-based epithermal neutron beam

    Raaijmakers, C. P. J.; Nottelman, E. L.; Konijnenberg, M. W.; Mijnheer, B. J.


    The aims of this study were (i) to determine the variation with time of the relevant beam parameters of a clinical reactor-based epithermal neutron beam for boron neutron capture therapy (BNCT) and (ii) to test a monitoring system for its applicability to monitor the dose delivered to the dose specification point in a patient treated with BNCT. For this purpose two fission chambers covered with Cd and two GM counters were positioned in the beam-shaping collimator assembly of the epithermal neutron beam. The monitor count rates were compared with in-phantom reference measurements of the thermal neutron fluence rate, the gamma-ray dose rate and the fast neutron dose rate, at a constant reactor power, over a period of 2 years. Differences in beam output, defined as the thermal neutron fluence rate at 2 cm depth in a phantom, of up to 15% were observed between various reactor cycles. A decrease in beam output of about 5% was observed in each reactor cycle. An unacceptable decrease of 50% in beam output due to malfunctioning of the beam filter assembly was detected. For safe and accurate treatment of patients, on-line monitoring of the beam is essential. Using the calibrated monitor system, the standard uncertainty in the total dose at depth due to variations with time of the beam output parameters has been reduced to a clinically acceptable value of 1% (one standard deviation).

  18. Design of a californium-based epithermal neutron beam for neutron capture therapy.

    Yanch, J C; Kim, J K; Wilson, M J


    The potential of the spontaneously fissioning isotope, 252Cf, to provide epithermal neutrons for use in boron neutron capture therapy (BNCT) has been investigated using Monte Carlo simulation. The Monte Carlo code MCNP was used to design an assembly composed of a 26 cm long, 11 cm radius cylindrical D2O moderator followed by a 64 cm long Al filter. Lithium filters are placed between the moderator and the filter and between the Al and the patient. A reflector surrounding the moderator/filter assembly is required in order to maintain adequate therapy flux at the patient position. An ellipsoidal phantom composed of skull- and brain-equivalent material was used to determine the dosimetric effect of this beam. It was found that both advantage depths and advantage ratios compare very favourably with reactor and accelerator epithermal neutron sources. The dose rate obtainable, on the other hand, is 4.1 RBE cGy min-1, based on a very large (1.0 g) source of 252Cf. This dose rate is two to five times lower than those provided by existing reactor beams and can be viewed as a drawback of using 252Cf as a neutron source. Radioisotope sources, however, do offer the advantage of in-hospital installation.

  19. Ultraslow Wave Nuclear Burning of Uranium-Plutonium Fissile Medium on Epithermal Neutrons

    Rusov, V D; Eingorn, M V; Chernezhenko, S A; Kakaev, A A


    For a fissile medium, originally consisting of uranium-238, the investigation of fulfillment of the wave burning criterion in a wide range of neutron energies is conducted for the first time, and a possibility of wave nuclear burning not only in the region of fast neutrons, but also for cold, epithermal and resonance ones is discovered for the first time. For the first time the results of the investigation of the Feoktistov criterion fulfillment for a fissile medium, originally consisting of uranium-238 dioxide with enrichments 4.38%, 2.00%, 1.00%, 0.71% and 0.50% with respect to uranium-235, in the region of neutron energies 0.015-10.0eV are presented. These results indicate a possibility of ultraslow wave neutron-nuclear burning mode realization in the uranium-plutonium media, originally (before the wave initiation by external neutron source) having enrichments with respect to uranium-235, corresponding to the subcritical state, in the regions of cold, thermal, epithermal and resonance neutrons. In order to...

  20. Petrology, geochemistry and U-Pb geochronology of magmatic rocks from the high-sulfidation epithermal Au-Cu Chelopech deposit, Srednogorie zone, Bulgaria

    Chambefort, Isabelle; Moritz, Robert; von Quadt, Albrecht


    The Chelopech deposit is one of the largest European gold deposits and is located 60 km east of Sofia, within the northern part of the Panagyurishte mineral district. It lies within the Banat-Srednegorie metallogenic belt, which extends from Romania through Serbia to Bulgaria. The magmatic rocks define a typical calc-alkaline suite. The magmatic rocks surrounding the Chelopech deposit have been affected by propylitic, quartz-sericite, and advanced argillic alteration, but the igneous textures have been preserved. Alteration processes have resulted in leaching of Na2O, CaO, P2O5, and Sr and enrichment in K2O and Rb. Trace element variation diagrams are typical of subduction-related volcanism, with negative anomalies in high field strength elements (HFSE) and light element, lithophile elements. HFSE and rare earth elements were relatively immobile during the hydrothermal alteration related to ore formation. Based on immobile element classification diagrams, the magmatic rocks are andesitic to dacitic in compositions. Single zircon grains, from three different magmatic rocks spanning the time of the Chelopech magmatism, were dated by high-precision U-Pb geochronology. Zircons of an altered andesitic body, which has been thrust over the deposit, yield a concordant 206Pb/238U age of 92.21 ± 0.21 Ma. This age is interpreted as the crystallization age and the maximum age for magmatism at Chelopech. Zircon analyses of a dacitic dome-like body, which crops out to the north of the Chelopech deposit, give a mean 206Pb/238U age of 91.95 ± 0.28 Ma. Zircons of the andesitic hypabyssal body hosting the high-sulfidation mineralization and overprinted by hydrothermal alteration give a concordant 206Pb/238U age of 91.45 ± 0.15 Ma. This age is interpreted as the intrusion age of the andesite and as the maximum age of the Chelopech epithermal high-sulfidation deposit. 176Hf/177Hf isotope ratios of zircons from the Chelopech magmatic rocks, together with published data on the

  1. Potential mineral resources, Payette National Forest, Idaho: description and probabilistic estimation

    Bookstrom, Arthur A.; Johnson, Bruce R.; Cookro, Theresa M.; Lund, Karen; Watts, Kenneth C.; King, Harley D.; Kleinkopf, Merlin D.; Pitkin, James A.; Sanchez, J. David; Causey, J. Douglas


    The Payette National Forest (PNF), in west-central Idaho, is geologically diverse and contains a wide variety of mineral resources. Mineral deposit types are grouped into locatable, leasable, and salable categories. The PNF has substantial past production and identified resources of locatable commodities, including gold, silver, copper, zinc, tungsten, antimony, mercury, and opal. Minor lignitic coal is the only leasable mineral resource known to be present in the PNF. Resources of salable commodities in the PNF include sand-and-gravel, basalt for crushed-rock aggregate, and minor gypsum. Locatable mineral resources are geographically divided between eastern and western parts of the PNF. The western PNF lies west of the Riggins-to-Cascade highway (US 95 - Idaho 55), and the eastern PNF is east of that highway. The western and eastern parts of the PNF are geologically distinctive and have different types of locatable mineral deposits, so their locatable mineral resources are described separately. Within the western and eastern parts of the PNF, locatable deposit types generally are described in order of decreasing geologic age. An expert panel delineated tracts considered geologically permissive and (or) favorable for the occurrence of undiscovered mineral deposits of types that are known to be present within or near the PNF. The panel also estimated probabilities for undiscovered deposits, and used numerical simulation, based on tonnage-grade distribution models, to derive estimates of in-situ metals contained. These estimates are summarized in terms of mean and median measures of central tendency. Most grade and tonnage distributions appear to be log-normal, with the median lower than the mean. Inasmuch as the mean is influenced by the largest deposits in the model tonnage-grade distribution, the median provides a lower measure of central tendency and a more conservative estimation of undiscovered resources.

  2. Design of epithermal neutron beam for clinical BNCT treatment at Slovenian TRIGA research reactor

    Maucec, Marko [Jozef Stefan Institute, Reactor Physics Division, Lubljana (Slovenia). E-mail:


    The Monte Carlo feasibility study of development of epithermal neutron beam for BNCT clinical trials on Jozef Stefan Institute (JSI) TRIGA reactor is presented. The investigation of the possible use of fission converter for the purpose of enhancement of neutron beam, as well as the set-up of TRIGA reactor core is performed. The optimization of the irradiation facility components is carried out and the configuration with the most favorable cost/performance ratio is proposed. The simulation results prove that a BNCT irradiation facility with performances, comparable to existing beams throughout the world, could be installed in the thermalizing column of the TRIGA reactor, quite suitable for the clinical treatments of human patients. (author)

  3. Evaluation of the effective dose during BNCT at TRR thermal column epithermal facility.

    Jarahi, Hossein; Kasesaz, Yaser; Saleh-Koutahi, Seyed Mohsen


    An epithermal neutron beam has been designed for Boron neutron Capture Therapy (BNCT) at the thermal column of Tehran Research Reactor (TRR) recently. In this paper the whole body effective dose, as well as the equivalent doses of several organs have been calculated in this facility using MCNP4C Monte Carlo code. The effective dose has been calculated by using the absorbed doses determined for each individual organ, taking into account the radiation and tissue weighting factors. The ICRP 110 whole body male phantom has been used as a patient model. It was found that the effective dose during BNCT of a brain tumor is equal to 0.90Sv. This effective dose may induce a 4% secondary cancer risk.

  4. Design of an epithermal column for BNCT based on D D fusion neutron facility

    Durisi, E.; Zanini, A.; Manfredotti, C.; Palamara, F.; Sarotto, M.; Visca, L.; Nastasi, U.


    Boron Neutron Capture Therapy (BNCT) is currently performed on patients at nuclear reactors. At the same time the international BNCT community is engaged in the development of alternative facilities for in-hospital treatments. This paper investigates the potential of a novel high-output D-D neutron generator, developed at Lawrence Berkeley National Laboratory (CA, USA), for BNCT. The simulation code MCNP-4C is used to realize an accurate study of the epithermal column in view of the treatment of deep tumours. Different materials and Beam Shaping Assemblies (BSA) are investigated and an optimized configuration is proposed. The neutron beam quality is defined by the standard free beam parameters, calculated averaging over the collimator aperture. The results are discussed and compared with the performances of other facilities.

  5. Design for an accelerator-based orthogonal epithermal neutron beam for boron neutron capture therapy.

    Allen, D A; Beynon, T D; Green, S


    This paper is concerned with the proposed Birmingham accelerator-based epithermal neutron beam for boron neutron capture therapy (BNCT). In particular, the option of producing a therapy beam at an orthogonal direction to the incoming protons is considered. Monte Carlo radiation transport simulations, both with and without a head phantom, have shown that an orthogonal beam geometry is not only acceptable but is indeed beneficial, in terms of a lower mean neutron energy and an enhanced therapeutic ratio for the same useful neutron fluence in the therapy beam. Typical treatment times for various beam options have been calculated, and range from 20 to 48 min with a 5 mA beam of 2.8 MeV protons, if the maximum photon-equivalent dose delivered to healthy tissue is to be 12.6 Gy Eq. The effects of proton beam diameter upon the therapy beam parameters have also been considered.

  6. Hydrologic models of modern and fossil geothermal systems in the Great Basin: Genetic implications for epithermal Au-Ag and Carlin-type gold deposits

    Person, M.; Banerjee, A.; Hofstra, A.; Sweetkind, D.; Gao, Y.


    The Great Basin region in the western United States contains active geothermal systems, large epithermal Au-Ag deposits, and world-class Carlin-type gold deposits. Temperature profiles, fluid inclusion studies, and isotopic evidence suggest that modern and fossil hydrothermal systems associated with gold mineralization share many common features, including the absence of a clear magmatic fluid source, discharge areas restricted to fault zones, and remarkably high temperatures (>200 ??C) at shallow depths (200-1500 m). While the plumbing of these systems varies, geochemical and isotopic data collected at the Dixie Valley and Beowawe geothermal systems suggest that fluid circulation along fault zones was relatively deep (>5 km) and comprised of relatively unexchanged Pleistocene meteoric water with small (enthalpy, ??18O, silica compositions of fluids and/or rocks, groundwater residence times, fluid inclusion homogenization temperatures, and apatite fission track anomalies. Our results suggest that these hydrothermal systems were driven by natural thermal convection along anisotropic, subvertical faults connected in many cases at depth by permeable aquifers within favorable lithostratigraphic horizons. Those with minimal fluid ?? 18O shifts are restricted to high-permeability fault zones and relatively small-scale (???5 km), single-pass flow systems (e.g., Beowawe). Those with intermediate to large isotopic shifts (e.g., epithermal and Carlin-type Au) had larger-scale (???15 km) loop convection cells with a greater component of flow through marine sedimentary rocks at lower water/rock ratios and greater endowments of gold. Enthalpy calculations constrain the duration of Carlin-type gold systems to probably concentrations suggest that the duration of the modern Beowawe system is enthalpy fluids. Computed fission track ages along the Carlin trend included the convective effects, and ranged between 91.6 and 35.3 Ma. Older fission track ages occurred in zones of

  7. Feasibility study on epithermal neutron field for cyclotron-based boron neutron capture therapy.

    Yonai, Shunsuke; Aoki, Takao; Nakamura, Takashi; Yashima, Hiroshi; Baba, Mamoru; Yokobori, Hitoshi; Tahara, Yoshihisa


    To realize the accelerator-based boron neutron capture therapy (BNCT) at the Cyclotron and Radioisotope Center of Tohoku University, the feasibility of a cyclotron-based BNCT was evaluated. This study focuses on optimizing the epithermal neutron field with an energy spectrum and intensity suitable for BNCT for various combinations of neutron-producing reactions and moderator materials. Neutrons emitted at 90 degrees from a thick (stopping-length) Ta target, bombarded by 50 MeV protons of 300 microA beam current, were selected as a neutron source, based on the measurement of angular distributions and neutron energy spectra. As assembly composed of iron, AlF3/Al/6LiF, and lead was chosen as moderators, based on the simulation trials using the MCNPX code. The depth dose distributions in a cylindrical phantom, calculated with the MCNPX code, showed that, within 1 h of therapeutic time, the best moderator assembly, which is 30-cm-thick iron, 39-cm-thick AlF3/Al/6LiF, and 1-cm-thick lead, provides an epithermal neutron flux of 0.7 x 10(9) [n cm(-2) s(-1)]. This results in a tumor dose of 20.9 Gy-eq at a depth of 8 cm in the phantom, which is 6.4 Gy-eq higher than that of the Brookhaven Medical Research Reactor at the equivalent condition of maximum normal tissue tolerance. The beam power of the cyclotron is 15 kW, which is much lower than other accelerator-based BNCT proposals.

  8. Accelerator-based epithermal neutron beam design for neutron capture therapy.

    Yanch, J C; Zhou, X L; Shefer, R E; Klinkowstein, R E


    Recent interest in the production of epithermal neutrons for use in boron neutron capture therapy (BNCT) has promoted an investigation into the feasibility of generating such neutrons with a high current proton accelerator. Energetic protons (2.5 MeV) on a 7Li target produce a spectrum of neutrons with maximum energy of roughly 800 keV. A number of combinations of D2O moderator, lead reflector, 6Li thermal neutron filtration, and D2O/6Li shielding will result in a useful epithermal flux of 1.6 x 10(8) n/s at the patient position. The neutron beam is capable of delivering 3000 RBE-cGy to a tumor at a depth of 7.5 cm in a total treatment time of 60-93 min (depending on RBE values used and based on a 24-cm diameter x 19-cm length D2O moderator). Treatment of deeper tumors with therapeutic advantage would also be possible. Maximum advantage depths (RBE weighted) of 8.2-9.2 (again depending on RBE values and precise moderator configuration) are obtained in a right-circular cylindrical phantom composed of brain-equivalent material with an advantage ratio of 4.7-6.3. A tandem cascade accelerator (TCA), designed and constructed at Science Research Laboratory (SRL) in Somerville MA, can provide the required proton beam parameters for BNCT of deep-seated tumors. An optimized configuration of materials required to shift the accelerator neutron spectrum down to therapeutically useful energies has been designed using Monte Carlo simulation in the Whitaker College Biomedical Imaging and Computation Laboratory at MIT. Actual construction of the moderator/reflector assembly is currently underway.

  9. Thick beryllium target as an epithermal neutron source for neutron capture therapy.

    Wang, C K; Moore, B R


    Accelerator-based intense epithermal neutron sources for Neutron Capture Therapy (NCT) have been considered as an alternative to nuclear reactors. Lithium (Li) has generally received the widest attention for this application, since the threshold energy is low and neutron yield is high. Because of the poor thermal and chemical properties of Li and the need for heat removal in the target, the design of Li targets has been quite difficult. Beryllium (Be) has been thought of as an alternative target because of its good thermal and chemical properties and reasonable neutron yield. However, in order to have a neutron yield comparable to that of a thick Li target bombarded with 2.5 MeV protons, the proton energy required for a thick Be target must be approaching 4 MeV. Consequently, the neutrons emitted are more energetic. In addition, a significant amount of high-energy gamma rays, which is undesirable, will occur when Be is bombarded with low-energy protons. Regardless of the more energetic neutrons and additional gamma rays, in this paper it is shown that it is possible to develop a high-quality and high-intensity epithermal neutron beam based on a thick Be target for NCT treatment. For a fixed proton current, the optimal Be-target-based beam (with 4-MeV protons) can produce a neutron beam, with both quality and intensity slightly better than those produced by the optimal Li-target-based beam (with 2.5-MeV protons). The single-session NCT treatment time for the optimal Be-target-based beam is estimated to be 88 min for a proton current of 50 mA.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. The Marianas-San Marcos vein system: characteristics of a shallow low sulfidation epithermal Au-Ag deposit in the Cerro Negro district, Deseado Massif, Patagonia, Argentina

    Vidal, Conrado Permuy; Guido, Diego M.; Jovic, Sebastián M.; Bodnar, Robert J.; Moncada, Daniel; Melgarejo, Joan Carles; Hames, Willis


    The Cerro Negro district, within the Argentinian Deseado Massif province, has become one of the most significant recent epithermal discoveries, with estimated reserves plus resources of ˜6.7 Moz Au equivalent. The Marianas-San Marcos vein system contains about 70 % of the Au-Ag resources in the district. Mineralization consists of Upper Jurassic (155 Ma) epithermal Au- and Ag-rich veins of low to intermediate sulfidation style, hosted in and genetically related to Jurassic intermediate composition volcanic rocks (159-156 Ma). Veins have a complex infill history, represented by ten stages with clear crosscutting relationships that can be summarized in four main episodes: a low volume, metal-rich initial episode (E1), an extended banded quartz episode with minor mineralization (E2), a barren waning stage episode (E3), and a silver-rich late tectonic-hydrothermal episode (E4). The first three episodes are interpreted to have formed at the same time and probably from fluids of similar composition: a 290-230 °C fluid dominated by meteoric and volcanic waters (-3‰ to -0‰ δ18Owater), with <3 % NaCl equivalent salinity and with a magmatic source of sulfur (-1 to -2 ‰ δ34Swater). Metal was mainly precipitated at the beginning of vein formation (episode 1) due to a combination of boiling at ˜600 to 800 m below the paleowater table, and associated mixing/cooling processes, as evidenced by sulfide-rich bands showing crustiform-colloform quartz, adularia, and chlorite-smectite banding. During episodes 2 and 3, metal contents progressively decrease during continuing boiling conditions, and veins were filled by quartz and calcite during waning stages of the hydrothermal system, and the influx of bicarbonate waters (-6 to -8.5 ‰ δ18Owater). Hydrothermal alteration is characterized by proximal illite, adularia, and silica zone with chlorite and minor epidote, intermediate interlayered illite-smectite and a distal chlorite halo. This assemblage is in agreement with

  11. Study on Minerogenetic Series and Mineralization pedigree of important minerals in Shandong Province%山东省重要矿种成矿系列成矿谱系研究

    倪振平; 倪志霄; 李秀章; 王立功


    以陈毓川院士“矿床成矿系列”理论为指导,以全省煤、油页岩、铁、铜、铅、锌、铝、金、银、钼、稀土、硫、萤石、重晶石、菱镁矿、钾、磷、金刚石、石膏、石墨、滑石、水泥用灰岩、膨润土等23个重要矿种为基础,辅以其他矿种,从山东省区域地质构造环境与区域成矿作用关系研究划分全省重要矿种成矿系列;按照鲁西陆块、胶北陆块和胶南-威海造山带构造单元建立全省区域成矿谱系,以揭示全省在不同地质历史时期、不同区域地质构造环境下成矿作用的时空演化关系。%Based on "Minerogenetic Series of Mineral Deposits"proposed by Chen Yuchuan , the authors suggest minerogenetic series of important minerals in Shandong province , through study on relationship of regional geolog-ical environment and regional mineralization , targeted at 23 important minerals including coal , oil shale, iron, cop-per, lead, zinc, aluminum, gold, silver, molybdenum, rare earth, sulfur, fluorite, barite, magnesite, potassium, phosphorus, diamond, gypsum, graphite, talc, cement limestone, bentonite, and other minerals.Regional miner-alization pedigree is established by tectonic units of Luxi landmass , Jiaobei landmass and Jiaonan -Weihai orogenic belt, to reveal temporal evolution relationship of mineralization in different geological history and different regional tectonic environment in Shandong Province .

  12. Measurements of gamma dose and thermal neutron fluence in phantoms exposed to a BNCT epithermal beam with TLD-700.

    Gambarini, G; Magni, D; Regazzoni, V; Borroni, M; Carrara, M; Pignoli, E; Burian, J; Marek, M; Klupak, V; Viererbl, L


    Gamma dose and thermal neutron fluence in a phantom exposed to an epithermal neutron beam for boron neutron capture therapy (BNCT) can be measured by means of a single thermoluminescence dosemeter (TLD-700). The method exploits the shape of the glow curve (GC) and requires the gamma-calibration GC (to obtain gamma dose) and the thermal-neutron-calibration GC (to obtain neutron fluence). The method is applicable for BNCT dosimetry in case of epithermal neutron beams from a reactor because, in most irradiation configurations, thermal neutrons give a not negligible contribution to the TLD-700 GC. The thermal neutron calibration is not simple, because of the impossibility of having thermal neutron fields without gamma contamination, but a calibration method is here proposed, strictly bound to the method itself of dose separation.

  13. Fluid flow and mineralization of Youjiang Basin in the Yunnan-Guizhou-Guangxi area, China

    王国芝; 胡瑞忠; 苏文超; 朱赖民


    Comprehensive studies, based on isotope geochemistry of C, H, O, S and Sr, chronology, common element and trace element geochemistry of fluid inclusions for the epithermal Au, As, Sb and Hg deposits in the Youjiang Basin and its peripheral areas, suggested that the ore fluid was the basin fluid with abundant metallic elements and the large-scale fluid flow of the same source in the late Yenshan stage was responsible for huge epithermal mineralization and silicification. The ore fluid flowed from the basin to the platform between the basin and the platform and migrated from the inter-platform basin to the isolated platform in the Youjiang Basin. The synsedimentary faults and paleokast surface acted respectively as main conduits for vertical and lateral fluid flow.

  14. Coarse-scaling adjustment of fine-group neutron spectra for epithermal neutron beams in BNCT using multiple activation detectors

    Liu, Yuan-Hao; Nievaart, Sander; Tsai, Pi-En; Liu, Hong-Ming; Moss, Ray; Jiang, Shiang-Huei


    In order to provide an improved and reliable neutron source description for treatment planning in boron neutron capture therapy (BNCT), a spectrum adjustment procedure named coarse-scaling adjustment has been developed and applied to the neutron spectrum measurements of both the Tsing Hua Open-pool Reactor (THOR) epithermal neutron beam in Taiwan and the High Flux Reactor (HFR) in The Netherlands, using multiple activation detectors. The coarse-scaling adjustment utilizes a similar idea as the well-known two-foil method, which adjusts the thermal and epithermal neutron fluxes according to the Maxwellian distribution for thermal neutrons and 1/ E distribution over the epithermal neutron energy region. The coarse-scaling adjustment can effectively suppress the number of oscillations appearing in the adjusted spectrum and provide better smoothness. This paper also presents a sophisticated 9-step process utilizing twice the coarse-scaling adjustment which can adjust a given coarse-group spectrum into a fine-group structure, i.e. 640 groups, with satisfactory continuity and excellently matched reaction rates between measurements and calculation. The spectrum adjustment algorithm applied in this study is the same as the well-known SAND-II.

  15. The alanine detector in BNCT dosimetry: Dose response in thermal and epithermal neutron fields

    Schmitz, T., E-mail: [Institute for nuclear chemistry, Johannes Gutenberg-University, Mainz D-55128 (Germany); Bassler, N. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, Aarhus 8000 (Denmark); Blaickner, M. [AIT Austrian Institute of Technology GmbH, Vienna A-1220 (Austria); Ziegner, M. [AIT Austrian Institute of Technology GmbH, Vienna A-1220, Austria and TU Wien, Vienna University of Technology, Vienna A-1020 (Austria); Hsiao, M. C. [Insitute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liu, Y. H. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Koivunoro, H. [Department of Physics, University of Helsinki, POB 64, FI-00014, Finland and HUS Medical Imaging Center, Helsinki University Central Hospital, FI-00029 HUS (Finland); Auterinen, I.; Serén, T.; Kotiluoto, P. [VTT Technical Research Centre of Finland, Espoo (Finland); Palmans, H. [National Physical Laboratory, Acoustics and Ionising Radiation Division, Teddington TW11 0LW, United Kingdom and Medical Physics Group, EBG MedAustron GmbH, Wiener Neustadt A-2700 (Austria); Sharpe, P. [National Physical Laboratory, Acoustics and Ionising Radiation Division, Teddington TW11 0LW (United Kingdom); Langguth, P. [Department of Pharmacy and Toxicology, University of Mainz, Mainz D-55128 (Germany); Hampel, G. [Institut für Kernchemie, Johannes Gutenberg-Universität, Mainz D-55128 (Germany)


    Purpose: The response of alanine solid state dosimeters to ionizing radiation strongly depends on particle type and energy. Due to nuclear interactions, neutron fields usually also consist of secondary particles such as photons and protons of diverse energies. Various experiments have been carried out in three different neutron beams to explore the alanine dose response behavior and to validate model predictions. Additionally, application in medical neutron fields for boron neutron capture therapy is discussed. Methods: Alanine detectors have been irradiated in the thermal neutron field of the research reactor TRIGA Mainz, Germany, in five experimental conditions, generating different secondary particle spectra. Further irradiations have been made in the epithermal neutron beams at the research reactors FiR 1 in Helsinki, Finland, and Tsing Hua open pool reactor in HsinChu, Taiwan ROC. Readout has been performed with electron spin resonance spectrometry with reference to an absorbed dose standard in a {sup 60}Co gamma ray beam. Absorbed doses and dose components have been calculated using the Monte Carlo codes FLUKA and MCNP. The relative effectiveness (RE), linking absorbed dose and detector response, has been calculated using the Hansen and Olsen alanine response model. Results: The measured dose response of the alanine detector in the different experiments has been evaluated and compared to model predictions. Therefore, a relative effectiveness has been calculated for each dose component, accounting for its dependence on particle type and energy. Agreement within 5% between model and measurement has been achieved for most irradiated detectors. Significant differences have been observed in response behavior between thermal and epithermal neutron fields, especially regarding dose composition and depth dose curves. The calculated dose components could be verified with the experimental results in the different primary and secondary particle fields. Conclusions: The

  16. Geological setting and styles of mineralization, north arm of Sulawesi, Indonesia

    Kavalieris, I.; van Leeuwen, Th. M.; Wilson, M.

    The north arm of Sulawesi consists of a Neogene island arc (North Sulawesi Arc) built upon Paleogene volcanic-sedimentary basement and underlain by oceanic crust, which is followed to the west by an arcuate, highly deformed terrane (neck of Sulawesi) characterized by metamorphic rocks and felsic granitoids belonging to the Sundaland continental margin. These two terranes have been contiguous during the Tertiary. The evolution of the North Sulawesi Arc is divided into two stages separated by collision of the north arm with the Sula Platform microcontinent in mid-Miocene time. During the Early Miocene a calc-alkaline andesitic arc developed in relation to west-directed subduction. Arc-continent collision resulted in back-arc thrusting, clockwise rotation of the north arm, and inception of subduction along the North Sulawesi Trench. Post-collisional magmatism in the North Sulawesi Arc produced felsic to mafic volcanic suites that are thought to be related primarily to rifting of the former arc rather than directly to subduction. In the neck of Sulawesi,LILE and LREE-element enriched, potassic granites (Dondo suite) of continental affinity (Sr 87/Sr 86 0.71) were generated. The north arm of Sulawesi is comparatively well mineralized. Porphyry CuAu and porphyry Mo mineralization is approximately 2-4 Ma old based on preliminary KAr dating and geological relationships. The former developed in an oceanic terrane following collision-related arc reversal, whereas the latter developed in a continental terrane that underwent lower crustal melting during extension following the same collision. Porphyry CuAu mineralization in the North Sulawesi Arc is associatedwith clusters of small hornblende diorite or quartz diorite stocks, but the specific volcanic environment above these intrusions and their magmatic affinity remain unknown. Mineralization related to porphyry CuAu districts includes CuAu skarn, polymetallic vein and high sulphidation epithermal Au (+enargite

  17. Epithermal neutron activation analysis of Cr(VI)-reducer basalt-inhabiting bacteria.

    Tsibakhashvili, Nelly Yasonovna; Frontasyeva, Marina Vladimirovna; Kirkesali, Elena Ivanovna; Aksenova, Nadezhda Gennadievna; Kalabegishvili, Tamaz Levanovich; Murusidze, Ivana Georgievich; Mosulishvili, Ligury Mikhailovich; Holman, Hoi-Ying N


    Epithermal neutron activation analysis (ENAA) has been applied to study elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance, demonstrating that the bacteria differ in their rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(V) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 microg/g of dry weight) indicate bacterial adaptation to the environmental conditions typical of the basalts. The concentrations of at least 12-19 different elements were determined in each type of bacteria simultaneously starting with the major to ultratrace elements. The range of concentrations spans over 8 orders of magnitude.

  18. Marine Gradients of Halogens in Moss Studied by Epithermal Neutron Activation Analysis

    Frontasyeva, M V


    Epithermal neutron activation analysis is known to be a powerful technique for the simultaneous study of chlorine, bromine and iodine in environmental samples. In this paper it is shown to be useful to elucidate marine gradients of these elements. Examples are from a transect study in northern Norway where samples of the feather moss Hylocomium splendens were collected at distances 0-300 km from the coastline. All three elements decreased exponentially as a function of distance from the ocean in the moss samples, strongly indicating that atmospheric supply from the marine environment is the predominant source of these elements to the terrestrial ecosystem. These results are compared with similar data for surface soils along the same gradients. Comparison is also made with previous data for halogens in moss in Norway obtained by conventional NAA and covering similar transects in other geographical regions. The Cl/Br and Br/I ratios in moss showed a regular change distance from the ocean in all transects, and h...

  19. A state-of-the-art epithermal neutron irradiation facility for neutron capture therapy

    Riley, K. J.; Binns, P. J.; Harling, O. K.


    At the Massachusetts Institute of Technology (MIT) the first fission converter-based epithermal neutron beam (FCB) has proven suitable for use in clinical trials of boron neutron capture therapy (BNCT). The modern facility provides a high intensity beam together with low levels of contamination that is ideally suited for use with future, more selective boron delivery agents. Prescriptions for normal tissue tolerance doses consist of 2 or 3 fields lasting less than 10 min each with the currently available beam intensity, that are administered with an automated beam monitoring and control system to help ensure safety of the patient and staff alike. A quality assurance program ensures proper functioning of all instrumentation and safety interlocks as well as constancy of beam output relative to routine calibrations. Beam line shutters and the medical room walls provide sufficient shielding to enable access and use of the facility without affecting other experiments or normal operation of the multipurpose research reactor at MIT. Medical expertise and a large population in the greater Boston area are situated conveniently close to the university, which operates the research reactor 24 h a day for approximately 300 days per year. The operational characteristics of the facility closely match those established for conventional radiotherapy, which together with a near optimum beam performance ensure that the FCB is capable of determining whether the radiobiological promise of NCT can be realized in routine practice.

  20. Experimental and theoretical evaluation of accelerator based epithermal neutron yields for BNCT

    Wielopolski, L.; Ludewig, H.; Powell, J. R.; Raparia, D.; Alessi, J. G.; Alburger, D. E.; Zucker, M. S.; Lowenstein, D. I.


    At BNL, we have evaluated the beam current required to produce a clinical neutron beam for Boron Neutron Capture Therapy (BNCT) with an epithermal neutron flux of 1012n/cm2/hr. Experiments were carried out on a Van de Graaff accelerator at the Radiological Research Accelerator Facility (RARAF) at Columbia University. A thick Li target was irradiated by protons with energies from 1.8 to 2.5 MeV. The neutron spectra resulting from the 7Li(p,n)7Be reaction, followed by various filter configurations, were determined by measuring pulse height distributions with a gas filled proton recoil spectrometer. These distributions were unfolded into neutron energy spectra using the PSNS code, from which the required beam currents were estimated to be about 5 mA. Results are in good agreement with calculations using the MCNP-4A transport code. In addition comparison was also made between the neutron flux obtained at the Brookhaven Medical Research Reactor (where clinical trials of BNCT are ongoing), and measurements at RARAF, using a 10BF3 detector in a phantom. These results also support the requirement for about 5 mA beam current.

  1. Dosimetric effects of beam size and collimation of epithermal neutrons for boron neutron capture therapy.

    Yanch, J C; Harling, O K


    A series of studies of "ideal" beams has been carried out using Monte Carlo simulation with the goal of providing guidance for the design of epithermal beams for boron neutron capture therapy (BNCT). An "ideal" beam is defined as a monoenergetic, photon-free source of neutrons with user-specified size, shape and angular dependence of neutron current. The dosimetric behavior of monoenergetic neutron beams in an elliptical phantom composed of brain-equivalent material has been assessed as a function of beam diameter and neutron emission angle (beam angle), and the results are reported here. The simulation study indicates that substantial differences exist in the dosimetric behavior of small and large neutron beams (with respect to the phantom) as a function of the extent of beam collimation. With a small beam, dose uniformity increases as the beam becomes more isotropic (less collimated); the opposite is seen with large beams. The penetration of thermal neutrons is enhanced as the neutron emission angle is increased with a small beam; again the opposite trend is seen with large beams. When beam size is small, the dose delivered per neutron is very dependent on the extent of beam collimation; this does not appear to be the case with a larger beam. These trends in dose behavior are presented graphically and discussed in terms of their effect on several figures of merit, the advantage depth, the advantage ratio, and the advantage depth-dose rate. Tables giving quick summaries of these results are provided.

  2. A design study for an accelerator-based epithermal neutron beam for BNCT.

    Allen, D A; Beynon, T D


    An achievable design concept for a boron neutron capture therapy (BNCT) facility, based on a high-current, low-energy proton accelerator, is described. Neutrons are produced within a thick natural lithium target, under bombardment from protons with an initial energy between 2.5 and 3.0 MeV. The proton current will be up to 10 mA. After gamma-ray filtering, the neutrons are partially moderated to epithermal energies within a heavy-water moderator, poisoned with 6Li to remove thermal neutrons. Monte Carlo modelling has been used to predict system performance in terms of neutron fluence rate and neutron and gamma-ray dose at the patient position. The relationship between the system performance and key parameters, such as proton energy, moderator depth and 6Li concentration, has been investigated. With a proton current of 10 mA, the facility is capable of providing a therapy beam with a useful neutron fluence rate of 10(9) cm-2 s-1 and a neutron dose per unit fluence of less than 6 x 10(-13) Gy cm2, with a gamma-ray contamination of the therapy beam of about 10(-13) Gy cm2.

  3. Designing accelerator-based epithermal neutron beams for boron neutron capture therapy.

    Bleuel, D L; Donahue, R J; Ludewigt, B A; Vujic, J


    The 7Li(p,n)7Be reaction has been investigated as an accelerator-driven neutron source for proton energies between 2.1 and 2.6 MeV. Epithermal neutron beams shaped by three moderator materials, Al/AlF3, 7LiF, and D2O, have been analyzed and their usefulness for boron neutron capture therapy (BNCT) treatments evaluated. Radiation transport through the moderator assembly has been simulated with the Monte Carlo N-particle code (MCNP). Fluence and dose distributions in a head phantom were calculated using BNCT treatment planning software. Depth-dose distributions and treatment times were studied as a function of proton beam energy and moderator thickness. It was found that an accelerator-based neutron source with Al/AlF3 or 7LiF as moderator material can produce depth-dose distributions superior to those calculated for a previously published neutron beam design for the Brookhaven Medical Research Reactor, achieving up to approximately 50% higher doses near the midline of the brain. For a single beam treatment, a proton beam current of 20 mA, and a 7LiF moderator, the treatment time was estimated to be about 40 min. The tumor dose deposited at a depth of 8 cm was calculated to be about 21 Gy-Eq.

  4. Spectrum-tuners for thermal and epithermal boron neutron capture therapy

    Gessaghi, Valeria [Instituto Balseiro, San Carlos de Bariloche (Argentina); Jatuff, Fabian E.; Esposto, Fernando J. [Investigacion Aplicada S.E. (INVAP), San Carlos de Bariloche (Argentina)


    The first condition for BNCT is the appropriate neutron beam spectrum tuning, with minimum damage due to undesired particles. This includes the proper design of filters, gamma shields, and collimator geometry and materials, as well as exit beam aperture size and beam shutters. The set of all these elements is called spectrum-tuner in this work, which presents the conceptual design for epithermal neutron therapy in a hypothetical 10-MW MTR-type research reactor. The design has a filter section and a collimator section, separated by a bismuth gamma shield of {approx}15cm. The collimator is composed of bismuth, with stainless-steel case. The neutrons exiting the filter are collimated from the filter assembly to a 20 cm diameter beam port at the patient location in approximately 1 m. With the MCNP-4.2 code, the design was tested and the particle fields characterized, showing the extend by which the length of the collimator section and the filter configuration affects beam intensity, angular divergence, and radial flatness of the beam. (author)

  5. Epithermal Neutron Activation Analysis (ENAA) of Cr(VI)-reducer Basalt-inhabiting Bacteria

    Tsibakhashvili, N Ya; Kirkesali, E I; Aksenova, N G; Kalabegishvili, T L; Murusidze, I G; Mosulishvili, L M; Holman, H Y N


    Epithermal neutron activation analysis (ENAA) has been applied to studying elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance (ESR) demonstrating that the bacteria differ in the rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(V) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 $\\mu $g/g of dry weight) indicate bacterial adaptation to the environmental condition...

  6. Mineral oils

    Furby, N. W.


    The characteristics of lubricants made from mineral oils are discussed. Types and compositions of base stocks are reviewed and the product demands and compositions of typical products are outlined. Processes for commercial production of mineral oils are examined. Tables of data are included to show examples of product types and requirements. A chemical analysis of three types of mineral oils is reported.

  7. Mineralogical, fluid inclusion, and stable isotope constraints on mechanisms of ore deposition at the Samgwang mine (Republic of Korea)—a mesothermal, vein-hosted gold-silver deposit

    Yoo, Bong Chul; Lee, Hyun Koo; White, Noel C.


    The Samgwang mine is located in the Cheongyang gold district (Cheonan Metallogenic Province) of the Republic of Korea. It consists of eight massive, gold-bearing quartz veins that filled NE- and NW-striking fractures along fault zones in Precambrian granitic gneiss of the Gyeonggi massif. Their mineralogy and paragenesis allow two separate vein-forming episodes to be recognized, temporally separated by a major faulting event. The ore minerals occur in quartz and calcite of stage I, associated with fracturing and healing of veins. Hydrothermal wall-rock alteration minerals of stage I include Fe-rich chlorite (Fe/(Fe+Mg) ratios 0.74-0.81), muscovite, illite, K-feldspar, and minor arsenopyrite, pyrite, and carbonates. Sulfide minerals deposited along with electrum during this stage include arsenopyrite, pyrite, pyrrhotite, sphalerite, marcasite, chalcopyrite, galena, argentite, pyrargyrite, and argentian tetrahedrite. Only calcite was deposited during stage II. Fluid inclusions in quartz contain three main types of C-O-H fluids: CO2-rich, CO2-H2O, and aqueous inclusions. Quartz veins related to early sulfides in stage I were deposited from H2O-NaCl-CO2 fluids (1,500-5,000 bar, average 3,200) with T htotal values of 200°C to 383°C and salinities less than about 7 wt.% NaCl equiv. Late sulfide deposition was related to H2O-NaCl fluids (140-1,300 bar, average 700) with T htotal values of 110°C to 385°C and salinities less than about 11 wt.% NaCl equiv. These fluids either evolved through immiscibility of H2O-NaCl-CO2 fluids as a result of a decrease in fluid pressure, or through mixing with deeply circulated meteoric waters as a result of uplift or unloading during mineralization, or both. Measured and calculated sulfur isotope compositions (δ34SH2S = 1.5 to 4.8‰) of hydrothermal fluids from the stage I quartz veins indicate that ore sulfur was derived mainly from a magmatic source. The calculated and measured oxygen and hydrogen isotope compositions (δ18OH2O

  8. ESR-dosimetry in thermal and epithermal neutron fields for application in boron neutron capture therapy

    Schmitz, Tobias


    Dosimetry is essential for every form of radiotherapy. In Boron Neutron Capture Therapy (BNCT) mixed neutron and gamma fields have to be considered. Dose is deposited in different neutron interactions with elements in the penetrated tissue and by gamma particles, which are always part of a neutron field. The therapeutic dose in BNCT is deposited by densely ionising particles, originating from the fragmentation of the isotope boron-10 after capture of a thermal neutron. Despite being investigated for decades, dosimetry in neutron beams or fields for BNCT remains complex, due to the variety in type and energy of the secondary particles. Today usually ionisation chambers combined with metal foils are used. The applied techniques require extensive effort and are time consuming, while the resulting uncertainties remain high. Consequently, the investigation of more effective techniques or alternative dosimeters is an important field of research. In this work the possibilities of ESR-dosimeters in those fields have been investigated. Certain materials, such as alanine, generate stable radicals upon irradiation. Using Electron Spin Resonance (ESR) spectrometry the amount of radicals, which is proportional to absorbed dose, can be quantified. Different ESR detector materials have been irradiated in the thermal neutron field of the research reactor TRIGA research reactor in Mainz, Germany, with five setups, generating different secondary particle spectra. Further irradiations have been conducted in two epithermal neutron beams. The detector response, however, strongly depends on the dose depositing particle type and energy. It is hence necessary to accompany measurements by computational modelling and simulation. In this work the Monte Carlo code FLUKA was used to calculate absorbed doses and dose components. The relative effectiveness (RE), linking absorbed dose and detector response, has been calculated using amorphous track models. For the simulation, detailed models of

  9. The design, construction and performance of a variable collimator for epithermal neutron capture therapy beams

    Riley, K. J.; Binns, P. J.; Ali, S. J.; Harling, O. K.


    A patient collimator for the fission converter based epithermal neutron beam (FCB) at the Massachusetts Institute of Technology Research Reactor (MITR-II) was built for clinical trials of boron neutron capture therapy (BNCT). A design was optimized by Monte Carlo simulations of the entire beam line and incorporates a modular construction for easy modifications in the future. The device was formed in-house by casting a mixture of lead spheres (7.6 mm diameter) in epoxy resin loaded with either 140 mg cm-3 of boron carbide or 210 mg cm-3 of lithium fluoride (95% enriched in 6Li). The cone shaped collimator allows easy field placement anywhere on the patient and is equipped with a laser indicator of central axis, beam's eye view optics and circular apertures of 80, 100, 120 and 160 mm diameter. Beam profiles and the collateral dose in a half-body phantom were measured for the 160 mm field using fission counters, activation foils as well as tissue equivalent (A-150) and graphite walled ionization chambers. Leakage radiation through the collimator contributes less than 10% to the total collateral dose up to 0.15 m beyond the edge of the aperture and becomes relatively more prominent with lateral displacement. The measured whole body dose equivalent of 24 ± 2 mSv per Gy of therapeutic dose is comparable to doses received during conventional therapy and is due principally (60-80%) to thermal neutron capture reactions with boron. These findings, together with the dose distributions for the primary beam, demonstrate the suitability of this patient collimator for BNCT.

  10. Physics design for the Brookhaven Medical Research Reactor epithermal neutron source.

    Wheeler, F J; Parsons, D K; Nigg, D W; Wessol, D E; Miller, L G; Fairchild, R G


    A collaborative effort by researchers at the Idaho National Engineering Laboratory and the Brookhaven National Laboratory has resulted in the design and implementation of an epithermal-neutron source at the Brookhaven Medical Research Reactor (BMRR). Large aluminum containers, filled with aluminum oxide tiles and aluminum spacers, were tailored to pre-existing compartments on the animal side of the reactor facility. A layer of cadmium was used to minimize the thermal-neutron component. Additional bismuth was added to the pre-existing bismuth shield to minimize the gamma component of the beam. Lead was also added to reduce gamma streaming around the bismuth. The physics design methods are outlined in this paper. Information available to date shows close agreement between calculated and measured beam parameters. The neutron spectrum is predominantly in the intermediate energy range (0.5 eV - 10 keV). The peak flux intensity is 6.4E + 12 n/(m2.s.MW) at the center of the beam on the outer surface of the final gamma shield. The corresponding neutron current is 3.8E + 12 n/(m2.s.MW). Presently, the core operates at a maximum of 3 MW. The fast-neutron KERMA is 3.6E-15 cGy/(n/m2) and the gamma KERMA is 5.0E-16 cGY/(n/m2) for the unperturbed beam. The neutron intensity falls off rapidly with distance from the outer shield and the thermal flux realized in phantom or tissue is strongly dependent on the beam-delimiter and target geometry.

  11. The design, construction and performance of a variable collimator for epithermal neutron capture therapy beams.

    Riley, K J; Binns, P J; Ali, S J; Harling, O K


    A patient collimator for the fission converter based epithermal neutron beam (FCB) at the Massachusetts Institute of Technology Research Reactor (MITR-II) was built for clinical trials of boron neutron capture therapy (BNCT). A design was optimized by Monte Carlo simulations of the entire beam line and incorporates a modular construction for easy modifications in the future. The device was formed in-house by casting a mixture of lead spheres (7.6 mm diameter) in epoxy resin loaded with either 140 mg cm(-3) of boron carbide or 210 mg cm(-3) of lithium fluoride (95% enriched in 6Li). The cone shaped collimator allows easy field placement anywhere on the patient and is equipped with a laser indicator of central axis, beam's eye view optics and circular apertures of 80, 100, 120 and 160 mm diameter. Beam profiles and the collateral dose in a half-body phantom were measured for the 160 mm field using fission counters, activation foils as well as tissue equivalent (A-150) and graphite walled ionization chambers. Leakage radiation through the collimator contributes less than 10% to the total collateral dose up to 0.15 m beyond the edge of the aperture and becomes relatively more prominent with lateral displacement. The measured whole body dose equivalent of 24 +/- 2 mSv per Gy of therapeutic dose is comparable to doses received during conventional therapy and is due principally (60-80%) to thermal neutron capture reactions with boron. These findings, together with the dose distributions for the primary beam, demonstrate the suitability of this patient collimator for BNCT.

  12. Multipurpose epithermal neutron beam on new research station at MARIA research reactor in Swierk-Poland

    Gryzinski, M.A.; Maciak, M. [National Centre for Nuclear Research, Andrzeja Soltana 7, 05-400 Otwock-Swierk (Poland)


    MARIA reactor is an open-pool research reactor what gives the chance to install uranium fission converter on the periphery of the core. It could be installed far enough not to induce reactivity of the core but close enough to produce high flux of fast neutrons. Special design of the converter is now under construction. It is planned to set the research stand based on such uranium converter in the near future: in 2015 MARIA reactor infrastructure should be ready (preparation started in 2013), in 2016 the neutron beam starts and in 2017 opening the stand for material and biological research or for medical training concerning BNCT. Unused for many years, horizontal channel number H2 at MARIA research rector in Poland, is going to be prepared as a part of unique stand. The characteristics of the neutron beam will be significant advantage of the facility. High flux of neutrons at the level of 2x10{sup 9} cm{sup -2}s{sup -1} will be obtainable by uranium neutron converter located 90 cm far from the reactor core fuel elements (still inside reactor core basket between so called core reflectors). Due to reaction of core neutrons with converter U{sub 3}Si{sub 2} material it will produce high flux of fast neutrons. After conversion neutrons will be collimated and moderated in the channel by special set of filters and moderators. At the end of H2 channel i.e. at the entrance to the research room neutron energy will be in the epithermal energy range with neutron intensity at least at the level required for BNCT (2x10{sup 9} cm{sup -2}s{sup -1}). For other purposes density of the neutron flux could be smaller. The possibility to change type and amount of installed filters/moderators which enables getting different properties of the beam (neutron energy spectrum, neutron-gamma ratio and beam profile and shape) is taken into account. H2 channel is located in separate room which is adjacent to two other empty rooms under the preparation for research laboratories (200 m2). It is

  13. Compton suppression method and epithermal NAA in the determination of nutrients and heavy metals in Nigerian food and beverages.

    Ahmed, Y A; Landsberger, S; O'Kelly, D J; Braisted, J; Gabdo, H; Ewa, I O B; Umar, I M; Funtua, I I


    We used in this study Compton suppression method and epithermal neutron activation analysis to determine the concentration of nutrients and heavy metals in Nigerian food and beverages. The work was performed at the University of Texas TRIGA Reactor by short, medium, and long irradiation protocols, using thermal flux of 1.4x10(12)n cm(-2)s(-1) and epithermal flux of 1.4x10(11)n cm(-2)s(-1). Application of Compton suppression method has reduced interferences from Compton scattered photons thereby allowing easy evaluation of Na, Cl, Ca, Cu, Mn, Mg, Co, Cr, Rb, Fe, and Se. The epithermal NAA method has enabled determination of Cd, As, Ba, Sr, Br, I, and V with little turn-around time. Quality Control and Quality Assurance of the method was tested by analyzing four Standard Reference Materials (non-fat powdered milk, apple leaves, citrus leaves, and peach leaves) obtained from National Institute for Standards and Technology. Our results show that sorghum, millet, and maize have high values of Zn, Mn, Fe, low values of Cd, As, and Se. Powdered milks, rice, beans, and soybeans were found to have moderate amounts of all the elements. Tobacco recorded high content of Cd, Mn, and As, whereas tea, tsobo leaves, Baobab leaves, and okro seed have more As values than others. However, biscuits, macaroni, spaghetti, and noodles show lower concentrations of all the elements. The distribution of these nutrients and heavy metals in these food and beverages shows the need to fortify biscuits and pastas with micro and macro-nutrients and reduce the use of tobacco, tea, tsobo leaves, Baobab leaves, and Okro seed to avoid intake of heavy elements.

  14. Maps showing mineral resource assessment for porphyry and stockwork deposits of copper, molybdenum, and tungsten and for stockwork and disseminated deposits of gold and silver in the Butte 1 degree by 2 degrees Quadrangle, Montana

    Elliott, J.E.; Moll, S.H.; Wallace, C.A.; Lee, G.K.; Antweiler, J.C.; Lidke, D.J.; Rowan, L.C.; Hanna, W.F.; Trautwein, C.M.; Dwyer, J.L.


    This report documents the assessment for potential occurrences of undiscovered porphyry and stockwork deposits of copper, molybdenum, and tungsten (porphyry Cu-Mo-W) and stockwork and disseminated deposits of gold and silver (disseminated Au-Ag) in the Butte 1 °X2° quadrangle. The Butte quadrangle, in west-central Montana, is one of the best known mineral producing regions in the U.S. Mining districts in the quadrangle, including the world famous Butte or Summit Valley district, have produced a variety of metallic and nonmetallic mineral commodities valued at more than $6.4 billion (at the time of production). Because of its importance as a mineral producing region, the Butte quadrangle was selected for study by the U.S. Geological Survey under the Conterminous United States Mineral Assessment Program (CUSMAP). Under this program, new data on geology, geochemistry, geophysics, geochronology, mineral resources, and remote sensing were collected and synthesized. The field and laboratory studies were supported, in part, by funding from the Geologic Framework and Synthesis Program and the Wilderness Program. The methods used in this resource assessment for porphyry Cu-Mo-W and disseminated Au-Ag deposits in the quadrangle include a compilation of all data, the development of descriptive occurrence models, and the analysis of data using techniques provided by a Geographic Information System (GIS). This map is one of several maps on the Butte 1 °X2° quadrangle. Other deposit types have been assessed for the Butte quadrangle, and maps (U.S. Geological Survey (USGS) Miscellaneous Investigation Series Maps) for each of the following have been prepared: Vein and replacement deposits of gold, silver, copper, lead, zinc, manganese, and tungsten (Elliott, Wallace, and others, 1992a) and skarn deposits of gold, silver, copper, tungsten, and iron (Elliott and others, 1992b ). Other publications resulting from this study include linear features map (Rowan and others, 1991

  15. gold mineralization in Masjeddaghi area, east of Jolfa, NW Iran

    Ali Imamalipour


    Full Text Available Two types of mineralization including porphyry copper and epithermal gold mineralization have occurred in relation with an intermediate volcano-plutonic complex in Masjeddaghi area. Different alterations including silica, advanced argillic, intermediate argillic and propylitic have been distinguished in relation with epithermal mineralization, which have a zonal pattern. Elemental mass gains and losses during alterations were calculated using Zr as an immobile monitor. Silica zone has enriched in SiO2 and relatively in Al2O3 and K2O, and has depleted in Na2O, MgO and CaO. Ba, Sr, Pb, Rb and Cu elements have also enriched. The advanced argillic zone shows enrichment in SO3, Al2O3, SiO2, K2O, MgO and L.O.I; and depletion in Fe2O3, CaO, Na2O, MnO and MgO. Barium, Cu, Sr and Zn have depleted in this zone. Propylitic zone has enriched in MgO, CaO, L.O.I and SiO2, and has depleted in Na2O and K2O. Geochemical and mineralogical evidences indicate that the hydrothermal leaching of mafic minerals in parent rocks and formation of quartz, kaolinite, sericite and alunite assemblage in advanced argillic zone; and chlorite, epidote and calcite assemblage in propylitic zone is responsible for the above mentioned chemical variations. It is likely that the gains and losses of elements have been controlled by agents such as water/rock ratios, temperature changes and chemistry of hydrothermal solutions. The CIA and MIA indicators in the altered rocks indicate the intensity of alteration in silica and advanced argillic zones in comparison with propylitic zone.

  16. Application of Epithermal Neutron Activation Analysis to Investigate Accumulation and Adsorption of Mercury by Spirulina platensis Biomass

    Mosulishvili, L M; Khizanishvili, A I; Frontasyeva, M V; Kirkesali, E I; Aksenova, N G


    Epithermal neutron activation analysis was used to study interaction of blue-green alga Spirulina platensis with toxic metal mercury. Various concentrations of Hg(II) were added to cell cultures in a nutrient medium. The dynamics of accumulation of Hg was investigated over several days in relation to Spirulina biomass growth. The process of Hg adsorption by Spirulina biomass was studied in short-time experiments. The isotherm of adsorption was carried out in Freindlich coordinates. Natural Spirulina biomass has potential to be used in the remediation of sewage waters at Hg concentrations \\sim 100 {\\mu}g/l.

  17. Boron neutron capture therapy (BNCT) for glioblastoma multiforme using the epithermal neutron beam at the Brookhaven Medical Research Reactor

    Capala, J. [Brookhaven National Lab., Upton, NY (United States); Diaz, A.Z.; Chadha, M. [Univ. Hospital, State Univ. of New York, NY (United States)] [and others


    The abstract describes evaluation of boron neutron capture therapy (BNCT) for two groups of glioblastoma multiforme patients. From September 1994 to February 1996 15 patients have been treated. In September 1997 another 34 patients were examined. Authors determined a safe starting dose for BNCT using epithermal neutrons and BPA-F. They have also evaluated adverse effects of BNCT at this starting dose. Therapeutic effectiveness of this starting dose has been evaluated. No significant side effects from BPA-F infusion or BNCT treatment were observed in normal brains.

  18. Epithermal Neutron Activation Analysis of Spirulina platensis Biomass, of the C-Phycocianin and of DNA Extracted from It

    Mosulishvili, L M; Belokobylsky, A I; Kirkesali, E I; Khizanishvili, A I; Pomyakushina, E V


    The epithermal neutron activation analysis (ENAA) was used for study of the biomass of Spirulina platensis. The background levels of concentration 27 macro-, micro- and trace elements ranging from 10^{-3} up to 10^{4} ppm were determined. It was found that the biomass of spirulina does not contain toxic elements above the tolerance levels and can be utilized as a matrix of pharmaceuticals based on it. The concentrations of basic elements in C-phycocianin and DNA extracted from Spirulina platensis were determined by ENAA. A comparison of the element content of a whole spirulina biomass with that of a refined C-phycocianin preparation was made.

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

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


    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. Geology of the epithermal Ag-Au Huevos Verdes vein system and San José district, Deseado massif, Patagonia, Argentina

    Dietrich, Andreas; Gutierrez, Ronald; Nelson, Eric P.; Layer, Paul W.


    The San José district is located in the northwest part of the Deseado massif and hosts a number of epithermal Ag-Au quartz veins of intermediate sulfidation style, including the Huevos Verdes vein system. Veins are hosted by andesitic rocks of the Bajo Pobre Formation and locally by rhyodacitic pyroclastic rocks of the Chon Aike Formation. New 40Ar/39Ar constraints on the age of host rocks and mineralization define Late Jurassic ages of 151.3 ± 0.7 Ma to 144.7 ± 0.1 Ma for volcanic rocks of the Bajo Pobre Formation and of 147.6 ± 1.1 Ma for the Chon Aike Formation. Illite ages of the Huevos Verdes vein system of 140.8 ± 0.2 and 140.5 ± 0.3 Ma are 4 m.y. younger than the volcanic host rock unit. These age dates are among the youngest reported for Jurassic volcanism in the Deseado massif and correlate well with the regional context of magmatic and hydrothermal activity. The Huevos Verdes vein system has a strike length of 2,000 m, with several ore shoots along strike. The vein consists of a pre-ore stage and three main ore stages. Early barren quartz and chalcedony are followed by a mottled quartz stage of coarse saccharoidal quartz with irregular streaks and discontinuous bands of sulfide-rich material. The banded quartz-sulfide stage consists of sulfide-rich bands alternating with bands of quartz and bands of chlorite ± illite. Late-stage sulfide-rich veinlets are associated with kaolinite gangue. Ore minerals are argentite and electrum, together with pyrite, sphalerite, galena, chalcopyrite, minor bornite, covellite, and ruby silver. Wall rock alteration is characterized by narrow (220°C. Kaolinite occurring with the late sulfide-rich veinlet stage indicates pH 315°, whereas strike directions of <315° are predicted with an induced dextral strike-slip movement. The components of the structural model appear to be present on a regional scale and are not restricted to the San José district.

  1. Mineral and energy resource assessment maps of the Mount Katmai, Naknek, and western Afognak quadrangles, Alaska

    Church, S.E.; Riehle, J.R.; Magoon, L.B.; Campbell, D.L.


    On the basis of new geologic mapping and exploration geochemical studies, we have provided a mineral and energy resource assessment of the Mount Katmai, Naknek, and western Afognak quadrangles, Alaska. We delineate four tracts of ground that have metallic mineral resources. The mineral deposit types considered in each tract are summarized in table 4. Estimates of the number of undiscovered mineral deposits have been made for porphyry copper and polymetallic vein deposits. We estimate that one undiscovered porphyry copper deposit is present in the Katmai study area at the ten percent probability level. Although the sampling density may be too low to give an accurate estimate of the number of undiscovered polymetallic vein deposits, we suggest that, at a minimum, there is a five percent probability for five or more undiscovered polymetallic vein deposits in the Katmai study area. In addition, several areas have potential for undiscovered porphyry molybdenum, massive sulfide, and epithermal gold and mercury deposits.

  2. Boron neutron capture therapy (BNCT). Recent aspect, a change from thermal neutron to epithermal neutron beam and a new protocol

    Nakagawa, Yoshinobu [Dept. of Neurosurgery National Kagawa Children' s Hospital, Zentsuji, Kagawa (Japan)


    Since 1968, One-hundred seventy three patients with glioblastoma (n=81), anaplastic astrocytoma (n=44), low grade astrocytoma (n=16) or other types of tumor (n=32) were treated by boron-neutron capture therapy (BNCT) using a combination of thermal neutron and BSH in 5 reactors (HTR n=13, JRR-3 n=1, MuITR n=98, KUR n=28, JRR-2 n=33). Out of 101 patients with glioma treated by BNCT under the recent protocol, 33 (10 glioblastoma, 14 anaplastic astrocytoma, 9 low grade astrocytoma) patients lived or have lived longer than 3 years. Nine of these 33 lived or have lived longer than 10 years. According to the retrospective analysis, the important factors related to the clinical results were tumor dose radiation dose and maximum radiation dose in thermal brain cortex. The result was not satisfied as it was expected. Then, we decided to introduce mixed beams which contain thermal neutron and epithermal neutron beams. KUR was reconstructed in 1996 and developed to be available to use mixed beams. Following the shutdown of the JRR-2, JRR-4 was renewed for medical use in 1998. Both reactors have capacity to yield thermal neutron beam, epithermal neutron beam and mixed beams. The development of the neutron source lead us to make a new protocol. (author)

  3. Shielding design of a treatment room for an accelerator-based epithermal neutron irradiation facility for BNCT.

    Evans, J F; Blue, T E


    Protecting the facility personnel and the general public from radiation exposure is a primary safety concern of an accelerator-based epithermal neutron irradiation facility. This work makes an attempt at answering the questions "How much?" and "What kind?" of shielding will meet the occupational limits of such a facility. Shielding effectiveness is compared for ordinary and barytes concretes in combination with and without borated polyethylene. A calculational model was developed of a treatment room , patient "scatterer," and the epithermal neutron beam. The Monte Carlo code, MCNP, was used to compute the total effective dose equivalent rates at specific points of interest outside of the treatment room. A conservative occupational effective dose rate limit of 0.01 mSv h-1 was the guideline for this study. Conservative Monte Carlo calculations show that constructing the treatment room walls with 1.5 m of ordinary concrete, 1.2 m of barytes concrete, 1.0 m of ordinary concrete preceded by 10 cm of 5% boron-polyethylene, or 0.8 m of barytes concrete preceded by 10 cm of 5% boron-polyethylene will adequately protect facility personnel.

  4. Simultaneous determination of 76As, 122Sb and 153Sm in Chinese medicinal herbs by epithermal neutron activation analysis.

    Chen, Chien-Yi


    Optimal conditions for the simultaneous determination of As, Sb and Sm in Chinese medicinal herbs using epithermal neutron activation analysis were investigated. The minimum detectable concentrations of 76As, 122Sb and 153Sm in lichen and medicinal herbs depended on the weight of the irradiated sample, and irradiation and decay durations. Optimal conditions were obtained by wrapping the irradiated target with 3.2 mm borated polyethylene neutron filters, which were adopted to screen the original reactor fission neutrons and to reduce the background activities of 38Cl, 24Na and 42K. Twelve medicinal herbs, commonly consumed by Taiwanese children as a diuretic treatment, were analysed since trace elements, such as As and Sb, in these herbs may be toxic when consumed in sufficiently large quantities over a long period. Various amounts of medicinal herbs, standardised powder, lichen and tomato leaves were weighed, packed into polyethylene bags, irradiated and counted under different conditions. The results indicated that about 350 mg of lichen irradiated for 24 h and counted for 20 min following a 30-60 h decay period was optimal for irradiation in a 10(11)n/cm s epithermal neutron flux. The implications of the content of the studied elements in Chinese medicinal herbs are discussed.

  5. 3D inversion of magnetic and electrical resistivity-induced polarization data for an epithermal Au-Ag and underlying porphyry deposit: A case study from British Columbia, Canada

    Abbassi, B.; Huebert, J.; Liu, L.; Lee, B.; Cheng, L.; Richards, J. P.; Unsworth, M. J.; Oldenburg, D.


    The Newton property is an epithermal Au-Ag deposit containing precious metals in association with disseminated sulfide minerals such as pyrite. This type of deposit often shows variable geological patterns, so it is important to find fast and cost-efficient methods for their exploration. Aeromagnetic surveys and ground electrical resistivity-induced polarization methods were applied over the Newton property. From preliminary 3D inversion of ZTEM and aeromagnetic data, and joint 3D inversion of electrical resistivity-induced polarization data, we show that low-resistivity and high-chargeability regions are signatures of disseminated sulfide mineralization. Potassic alteration, characterized by hydrothermal biotite (now mostly chloritized) and magnetite is also present locally, and may be related to underlying porphyry-type mineralization. This type of alteration can be identified from its magnetic signature, but the occurrence of other magnetic formations in the deposit area made interpretations of magnetic data difficult. We show that filtering geological noises related to background magnetic anomalies is an essential step in focusing on potassic alteration zones. We used electrical resistivity and induced polarization chargeability models to remove the signals of barren magnetic zones to focus on the susceptibilities pertaining to deep potassic alterations. In order to test the credibility of these interpretations, extensive petrophysical measurements (magnetic susceptibility, electrical resistivity, and gamma ray spectra) were collected on drill-core samples. We show that potassic alteration can also be characterized accurately from high levels of potassium to thorium ratio (K/Th) in gamma ray spectrometric measurements, and that this correlation is stronger than the magnetic signal (likely because hydrothermal magnetite is variable in abundance). Therefore, we focused on magnetic susceptibility values correlated with high K/Th ratios in order to reduce the

  6. Applicability of near-infrared hyperspectral imagery (NIR-HI) for sensor based sorting of an epithermal Au-Ag ore

    Dalm, M.; Buxton, M.W.N.; Van Ruitenbeek, F.J.A.


    In the presented study test work was performed with near-infrared hyperspectral imagery (NIR-HI) on 36 ore samples from a South-American epithermal Au-Ag mine. The aim of the test work was to investigate if NIR-HI provides information about the alteration mineralogy of samples that can be used to pr

  7. Comparison of measured parameters from a 24-keV and a broad spectrum epithermal neutron beam for neutron capture therapy: an identification of consequential parameters.

    Fairchild, R G; Saraf, S K; Kalef-Ezra, J; Laster, B H


    Epithermal neutron beams are under development in a number of locations in the U.S. and abroad. The increased penetration in tissue provided by these neurons should circumvent problems associated with the rapid attenuation of thermal neutron beams encountered in previous clinical trials of neutron capture therapy (NCT). Physical and radiobiological experiments with two "intermediate energy" or "epithermal" beams have been reported. A comparison is made here between the 24-keV iron-filtered beam at Harwell, England, and the broad-spectrum Al2 O3 moderated beam at the Brookhaven Medical Research Reactor (BMRR). In addition, parameters which are relevant for NCT, and which are best suited for evaluation and comparison of beams, are discussed. Particular attention is paid to the mean neutron energy which can be tolerated without significant reduction of therapeutic gain (TG), where TG is the ratio of tumor dose to maximum normal tissue dose. It is suggested that the simplest and most meaningful parameters for comparison of beam intensity and purity are the epithermal neutron fluence rate, and the fast neutron dose per epithermal neutron (4.2 X 10(-11) rad/neutron for the broad-spectrum beam and 29 X 10(-11) rad/neutron for the 24-keV beam). While the Al2O3 beam is close to optimal, the 24-keV beam produces a significant fast neutron dose which results in a lower TG.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Characteristics of Mineralized Volcanic Centers in Javanese Sunda Island Arc, Indonesia

    Setijadji, L. D.; Imai, A.; Watanabe, K.


    The subduction-related arc magmatism in Java island, Sunda Arc, Indonesia might have started in earliest Tertiary period, but the distinctively recognizable volcanic belts related with Java trench subduction occurred since the Oligocene. We compiled geoinformation on volcanic centers of different epochs, distribution of metallic mineral deposits, petrochemistry of volcanic rocks, geologic structures, and regional gravity image in order to elucidate characteristics of the known mineralized volcanic centers. Metallic deposits are present in various styles from porphyry-related, high-sulfidation, and low-sulfidation epithermal systems; all related with subaerial volcanism and subvolcanic plutonism. Only few and small occurrences of volcanigenic massive sulfides deposits suggest that some mineralization also occurred in a submarine environment. Most locations of mineral deposits can be related with location of Tertiary volcanic centers along the volcanic arcs (i.e. volcanoes whose genetic link with subduction is clear). On the other side there is no mineralization has been identified to occur associated with backarc magmatism whose genetic link with subduction is under debate. There is strong evidence that major metallic deposit districts are located within compressive tectonic regime and bound by coupling major, deep, and old crustal structures (strike-slip faults) that are recognizable from regional gravity anomaly map. So far the most economical deposits and the only existing mines at major industry scale are high-grade epithermal gold deposits which are young (Upper Miocene to Upper Pliocene), concentrated in Bayah dome complex in west Java, and are associated with alkalic magmatism-volcanism. On the other hand, known porphyry Cu-Au deposits are associated with old (Oligocene to Upper Miocene) stocks, and except for one case, all deposits are located in east Java. Petrochemical data suggest a genetic relationship between porphyry mineralization with low- to

  9. Aggregate and Mineral Resources - Minerals

    NSGIC State | GIS Inventory — This point occurrence data set represents the current mineral and selected energy resources of Utah. The data set coordinates were derived from USGS topographic maps...

  10. Optimization of the Epithermal Neutron Beam for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor

    Hu, Jih-Perng; Rorer, David C.; Reciniello, Richard N.; Holden, Norman E.


    Clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumor had been carried out for half a decade, using an epithermal neutron beam at the Brookhaven Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new protocols. Details of the conceptual design to produce a higher intensity, more forward-directed neutron beam with less contamination from gamma rays, fast and thermal neutrons are presented here for their potential applicability to other reactor facilities. Monte Carlo calculations were used to predict the flux and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use.

  11. Optimization of the epithermal neutron beam for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor.

    Hu, Jih-Perng; Reciniello, Richard N; Holden, Norman E


    The use of epithermal neutron beam in clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumors had been carried out for half a decade at the Brookhaven's Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new BNCT protocols. Details of the conceptual design to produce a highly intensified and focused neutron beam with less gamma and neutron contamination in tissues are presented here for their potential applicability to other reactor facilities. Neutron-photon coupled Monte Carlo calculations were used to predict the flux, current, heating, and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use.

  12. In-phantom characterisation studies at the Birmingham Accelerator-Generated epIthermal Neutron Source (BAGINS) BNCT facility.

    Culbertson, Christopher N; Green, Stuart; Mason, Anna J; Picton, David; Baugh, Gareth; Hugtenburg, Richard P; Yin, Zaizhe; Scott, Malcolm C; Nelson, John M


    A broad experimental campaign to validate the final epithermal neutron beam design for the BNCT facility constructed at the University of Birmingham concluded in November 2003. The final moderator and facility designs are overviewed briefly, followed by a summary of the dosimetric methods and presentation of a small subset of the results from this campaign. The dual ionisation chamber technique was used together with foil activation to quantify the fast neutron, photon, and thermal neutron beam dose components in a large rectangular phantom exposed to the beam with a 12 cm diameter beam delimiter in place. After application of a normalisation factor, dose measurements agree with in-phantom MCNP4C predictions within 10% for the photon dose, within 10% for thermal neutron dose, and within 25% for the proton recoil dose along the main beam axis.

  13. Geochemistry of sediments and surface soils from the Nile Delta and lower Nile valley studied by epithermal neutron activation analysis

    Arafa, Wafaa M.; Badawy, Wael M.; Fahmi, Naglaa M.; Ali, Khaled; Gad, Mohamed S.; Duliu, Octavian G.; Frontasyeva, Marina V.; Steinnes, Eiliv


    The distributions of 36 major and trace elements in 40 surface soil and sediment samples collected from the Egyptian section of the river Nile were determined by epithermal neutron activation analysis and compared with corresponding data for the Upper Continental Crust and North American Shale Composite. Their relative distributions indicate the presence of detrital material of igneous origin, most probably resulting from weathering on Ethiopian highlands and transported by the Blue Nile, the Nile main tributary. The distributions of the nickel, zinc, and arsenic contents suggest that the lower part of the Nile and its surroundings including the Nile Delta is not seriously polluted with metals from local human activity. The geographical distributions of Na, Cl, and I as well as results of principal component analysis suggest atmospheric supply of these elements from the ocean. In general the present data may contribute to a better understanding of the geochemistry of the Nile sediments.

  14. Fumarolic minerals

    Balic Zunic, Tonci; Garavelli, Anna; Jakobsson, Sveinn Peter


    The fumarolic mineralogy of the Icelandic active volcanoes, the Tyrrhenian volcanic belt (Italy) and the Aegean active arc (Greece) is investigated, and literature data surveyed in order to define the characteristics of the European fumarolic systems. They show broad diversity of mineral...... associations, with Vesuvius and Vulcano being also among the world localities richest in mineral species. Volcanic systems, which show recession over a longer period, show fumarolic development from the hightemperature alkaline halide/sulphate, calcic sulphate or sulphidic parageneses, synchronous...... fluctuations in activity, illustrated by the example of Vulcano where the high-temperature association appears intermittently. A full survey of the mineral groups and species is given in respect to their importance and appearance in fumarolic associations....

  15. Thermal and epithermal neutron fluence rate gradient measurements by PADC detectors in LINAC radiotherapy treatments-field

    Barrera, M. T., E-mail:; Barros, H.; Pino, F.; Sajo-Bohus, L. [Universidad Simón Bolívar, Nuclear Physics Laboratory, Sartenejas, Caracas (Venezuela, Bolivarian Republic of); Dávila, J. [Física Médica C. A. and Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of)


    LINAC VARIAN 2100 is where energetic electrons produce Bremsstrahlung radiation, with energies above the nucleon binding energy (E≈5.5MeV). This radiation induce (γ,n) and (e,e’n) reactions mainly in the natural tungsten target material (its total photoneutron cross section is about 4000 mb in a energy range from 9-17 MeV). These reactions may occur also in other components of the system (e.g. multi leaf collimator). During radiation treatment the human body may receive an additional dose inside and outside the treated volume produced by the mentioned nuclear reactions. We measured the neutron density at the treatment table using nuclear track detectors (PADC-NTD). These covered by a boron-converter are employed, including a cadmium filter, to determine the ratio between two groups of neutron energy, i.e. thermal and epithermal. The PADC-NTD detectors were exposed to the radiation field at the iso-center during regular operation of the accelerator. Neutron are determined indirectly by the converting reaction {sup 10}B(n,α){sup 7}Li the emerging charged particle leave their kinetic energy in the PADC forming a latent nuclear track, enlarged by chemical etching (6N, NaOH, 70°C). Track density provides information on the neutron density through calibration coefficient (∼1.6 10{sup 4} neutrons /track) obtained by a californium source. We report the estimation of the thermal and epithermal neutron field and its gradient for photoneutrons produced in radiotherapy treatments with 18 MV linear accelerators. It was obsered that photoneutron production have higher rate at the iso-center.

  16. Angelaíta en la paragénesis del distrito Los Manantiales, provincia del Chubut: Una nueva especie mineral Angelaite in the paragenesis of Los Manantiales district, Chubut, Argentina: a new mineral species

    M.K. de Brodtkorb


    Full Text Available Angelaíta, Cu2AgPbBiS2 , una nueva especie mineral, fue localizada en la mina Ángela, mineralización de tipo IS del distrito Los Manantiales, Chubut, Argentina. La paragénesis incluye esfalerita, pirita, calcopirita, galena y en menor cantidad arsenopirita, betekhtinita, bornita, matildita, oro, plata, electrum, telurio, cervelleíta y hematita. La galena presenta numerosas inclusiones de angelaíta, aikinita, wittichenita y miharaíta. Esta paragénesis se presenta en vetas asociada a diferentes rocas volcánicas de la Formación Lonco Trapial de edad jurásica. La composición química de angelaíta fue obtenida con una microsonda electrónica. Se presenta en granos anhedrales de 10-100mm, es de color gris verdoso, moderadamente pleocroica y anisótropa.Angelaíte Cu2AgPbBiS2, a new mineral species, occurs in Mina Ángela, an IS type mineralization at the Los Manantiales district. The assemblage contains sphalerite, pyrite, chalcopyrite, galena with numerous inclusions of angelaíte, aikinite, miharaíte, and in smaller amounts arsenopyrite, betekhtinite, bornite, matildite, gold, silver, electrum, tellurium cervelleíte and hematite. Galena presents numerous inclusions of angelaíta, aikinita, wittichenita y miharaíta. This paragenesis occurs in veins associated with different volcanic rocks of the jurassic Lonco Trapial Formation. Angelaíte was observed as anhedral grains of 10-100mm, greenish grey in colour, moderately pleochroic and anisotropic.

  17. Molecular recognition by gold, silver and copper nanoparticles.

    Tauran, Yannick; Brioude, Arnaud; Coleman, Anthony W; Rhimi, Moez; Kim, Beonjoom


    The intrinsic physical properties of the noble metal nanoparticles, which are highly sensitive to the nature of their local molecular environment, make such systems ideal for the detection of molecular recognition events. The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles. In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization. A brief discussion of the three common methods of functionalization: Electrostatic adsorption; Chemisorption; Affinity-based coordination is given. In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition. In the main section the various types of capping agents for molecular recognition; nucleic acid coatings, protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications. Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition. For the proteins the recognition properties of antibodies form the core of the section. With respect to the supramolecular systems the cyclodextrins, calix[n]arenes, dendrimers, crown ethers and the cucurbitales are treated in depth. Finally a short section deals with the possible toxicity of the nanoparticles, a concern in public health.

  18. Molecular recognition by gold, silver and copper nanoparticles


    The intrinsic physical properties of the noble metal nanoparticles, which are highly sensitive to the nature of their local molecular environment, make such systems ideal for the detection of molecular recognition events. The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles. In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization. A brief discussion of the three common metho...

  19. Molecular recognition by gold, silver and copper nanoparticles

    Tauran, Yannick; Brioude, Arnaud; Coleman, Anthony W; Rhimi, Moez; Kim, Beonjoom


    The intrinsic physical properties of the noble metal nanoparticles, which are highly sensitive to the nature of their local molecular environment, make such systems ideal for the detection of molecular recognition events. The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles. In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization. A brief discussion of the three common methods of functionalization: Electrostatic adsorption; Chemisorption; Affinity-based coordination is given. In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition. In the main section the various types of capping agents for molecular recognition; nucleic acid coatings, protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications. Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition. For the proteins the recognition properties of antibodies form the core of the section. With respect to the supramolecular systems the cyclodextrins, calix[n]arenes, dendrimers, crown ethers and the cucurbitales are treated in depth. Finally a short section deals with the possible toxicity of the nanoparticles, a concern in public health. PMID:23977421

  20. Molecular recognition by gold, silver and copper nanoparticles

    Yannick; Tauran; Arnaud; Brioude; Anthony; W; Coleman; Moez; Rhimi; Beonjoom; Kim


    The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition events.The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles.In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization.A brief discussion of the three common methods of functionalization:Electrostatic adsorption;Chemisorption;Affinity-based coordination is given.In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition.In the main section the various types of capping agents for molecular recognition;nucleic acid coatings,protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications.Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition.For the proteins the recognition properties of antibodies form the core of the section.With respect to the supramolecular systems the cyclodextrins,calix[n]arenes,dendrimers,crown ethers and the cucurbitales are treated in depth.Finally a short section deals with the possible toxicity of the nanoparticles,a concern in public health.

  1. Mineral resources of high-tech metals in Russia: State of the art and outlook

    Bortnikov, N. S.; Volkov, A. V.; Galyamov, A. L.; Vikent'ev, I. V.; Aristov, V. V.; Lalomov, A. V.; Murashov, K. Yu.


    Seven main ore-forming systems—porphyry and epithermal; orogenic related to granitic intrusions; magmatic ultramafic; volcanic-hosted massive sulfide and volcanic-sedimentary; sedimentary basins; related to alkaline magmatic activity; and placers and weathering mantles—are sources of high-tech critical metals. The following promising types of ore deposits containing high-tech critical metals as by-products are recognized: Cu-Mo porphyry, Fe-Cu-Au and Pb-Zn skarn, base-metal epithermal, volcanic-hosted massive sulfide, base-metal stratiform, various tin deposits, and placers containing rare metals including REE. The mineral resources of critical metals in Russia are compared with those known in other countries. The contents of high-tech critical metals in ores of some noble-metal deposits of the Russian Northeast are reported. It is shown that the subsurface of Russia possesses considerable mineral resource potential for hightech critical metals, which allows new enterprises to be created or production of operating enterprises to increase.

  2. Mineral bioprocessing

    Torma, A.E.


    In the last 25 years, the introduction of biotechnological methods in hydrometallurgy has created new opportunities and challenges for the mineral processing industry. This was especially true for the production of metal values from mining wastes and low-and-complex-grade mineral resources, which were considered economically not amenable for processing by conventional extraction methods. Using bio-assisted heap, dump and in-situ leaching technologies, copper and uranium extractions gained their first industrial applications. The precious metal industries were the next to adopt the bio-preoxidation technique in the extraction of gold from refractory sulfide-bearing ores and concentrates. A variety of other bioleaching opportunities exist for nickel, cobalt, cadmium and zinc sulfide leaching. Recently developed bioremediation methods and biosorption technologies have shown a good potential for industrial applications to remove trace heavy metal and radionuclide concentrations from contaminated soils, and mining and processing effluents.

  3. Characterization of the Bnct Epithermal Column of the Fast Reactor Tapiro (enea) and Dose Measurements in Phantom Utilising Not-Conventional Detection

    Gambarini, G.; Colombi, C.; Lietti, B.; Prestini, P.; Fiorani, O.; Perrone, A.; Rosi, G.; Agosteo, S.; Riva, A.


    The epithermal column of TAPIRO reactor has been characterized and in-phantom dose has been imaged, with the purpose of determining parameters and data whose knowledge will be of main importance for future experimentation regarding boron neutron capture therapy (BNCT). In-phantom measurements have been carried out mainly utilizing a recently developed method for absorbed dose imaging, based on gel-dosimeters. Gel-dosimeters have revealed to give significant support to thermal or epithermal neutron dosimetry: in fact, the modality of energy release in gel-dosimeters is very similar to that in tissue, and with proper adjustment of the isotopic composition of gel matrix, the various dose components are separated.

  4. A phantom experiment for the evaluation of whole body exposure during BNCT using cyclotron-based epithermal neutron source (C-BENS)

    Tsukamoto, T., E-mail: [Graduate School of Engineering, Kyoto University, Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Tanaka, H.; Yoshinaga, H. [Research Reactor Institute, Kyoto University, Asashiro-nishi 2-1010, Kumatori-cho, Osaka 590-0494 (Japan); Mitsumoto, T. [Sumitomo Heavy Industries, Ltd., Osaki 2-1-1, Shinagawa, Tokyo 141-6025 (Japan); Maruhashi, A.; Ono, K.; Sakurai, Y. [Research Reactor Institute, Kyoto University, Asashiro-nishi 2-1010, Kumatori-cho, Osaka 590-0494 (Japan)


    At Kyoto University Research Reactor Institute (KURRI), cyclotron-based epithermal neutron source was installed in December 2008, and the supplementary construction works have been performed. As of December 2010, the various irradiation characteristics important for BNCT were mostly evaluated. The whole body exposure during BNCT medical irradiation is one of the important characteristics. In this article, measurements of absorbed dose for thermal and fast neutrons and gamma-ray at ten positions corresponding to important organs are reported.

  5. Sensitivity studies of beam directionality, beam size, and neutron spectrum for a fission converter-based epithermal neutron beam for boron neutron capture therapy.

    Sakamoto, S; Kiger, W S; Harling, O K


    Sensitivity studies of epithermal neutron beam performance in boron neutron capture therapy are presented for realistic neutron beams with varying filter/moderator and collimator/delimiter designs to examine the relative importance of neutron beam spectrum, directionality, and size. Figures of merit for in-air and in-phantom beam performance are calculated via the Monte Carlo technique for different well-optimized designs of a fission converter-based epithermal neutron beam with head phantoms as the irradiation target. It is shown that increasing J/phi, a measure of beam directionality, does not always lead to corresponding monotonic improvements in beam performance. Due to the relatively low significance, for most configurations, of its effect on in-phantom performance and the large intensity losses required to produce beams with very high J/phi, beam directionality should not be considered an important figure of merit in epithermal neutron beam design except in terms of its consequences on patient positioning and collateral dose. Hardening the epithermal beam spectrum, while maintaining the specific fast neutron dose well below the inherent hydrogen capture dose, improves beam penetration and advantage depth and, as a desirable by-product, significantly increases beam intensity. Beam figures of merit are shown to be strongly dependent on beam size relative to target size. Beam designs with J/phi approximately 0.65-0.7, specific fast neutron doses of 2-2.6x10(-13) Gy cm2/n and beam sizes equal to or larger than the size of the head target produced the deepest useful penetration, highest therapeutic ratios, and highest intensities.

  6. Epithermal neutron activation, radiometric, correlation and principal component analysis applied to the distribution of major and trace elements in some igneous and metamorphic rocks from Romania

    Cristache, C.I. [National Institute of Research and Development for Physics and Nuclear Engineering Horia-Hulubei, P.O. Box MG-6, 077125 Magurele, Ilfov (Romania); Duliu, O.G. [University of Bucharest, Department of Atomic and Nuclear Physics, P.O. Box MG-11, 077125 Magurele, Ilfov (Romania)], E-mail:; Culicov, O.A.; Frontasyeva, M.V. [Joint Institute of Nuclear Research, 6, Joliot Curie str. 141980, Dubna (Russian Federation); Ricman, C. [Geological Institute of Romania, 1 Caransebes Street, 012271 Bucharest (Romania); Toma, M. [National Institute of Research and Development for Physics and Nuclear Engineering Horia-Hulubei, P.O. Box MG-6, 077125 Magurele, Ilfov (Romania)


    Six major (Na, Al, K, Ca, Ti, Fe) and 28 trace (Sc, Cr, V, Mn, Co, Zn, Cu, As, Br, Sr, Rb, Zr, Mo, Sn, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Hf, Ta, W, Th and U) elements were determined by epithermal neutron activation analysis (ENAA) in nine Meridional Carpathian and Macin Mountains samples of igneous and metamorphic rocks. Correlation and principal factor analysis were used to interpret data while natural radionuclides radiometry shows a good correlation with ENAA results.

  7. Epithermal neutron activation, radiometric, correlation and principal component analysis applied to the distribution of major and trace elements in some igneous and metamorphic rocks from Romania.

    Cristache, C I; Duliu, O G; Culicov, O A; Frontasyeva, M V; Ricman, C; Toma, M


    Six major (Na, Al, K, Ca, Ti, Fe) and 28 trace (Sc, Cr, V, Mn, Co, Zn, Cu, As, Br, Sr, Rb, Zr, Mo, Sn, Sb, Ba, Cs, La, Ce, Nd, Eu, Sm, Tb, Hf, Ta, W, Th and U) elements were determined by epithermal neutron activation analysis (ENAA) in nine Meridional Carpathian and Macin Mountains samples of igneous and metamorphic rocks. Correlation and principal factor analysis were used to interpret data while natural radionuclides radiometry shows a good correlation with ENAA results.

  8. Design calculations of an epithermal neutron beam and development of a treatment planning system for the renovation of thor for boron neutron capture therapy

    Liu, Y-W H.; Teng, Y.H.; Liao, M.Z. [National Tsing Hua Univ., Department of Engineering and System Science, Taiwan (China)


    Tsing Hua University was recently granted by National Science Council a five-year project to renovate its Open-Pool reactor (THOR) for boron neutron capture therapy. With this support, the whole graphite blocks in the original thermal column region can be removed for redesigning and constructing a better epithermal neutron beam. THOR is a 1 MW research reactor. The cross section area of the core facing the thermal column is 60 cm x 50 cm. By using 60 cm FLUENTAL plus 10 cm Pb, with cross section area of 70 cm x 60 cm and surrounded by 6 cm thick PbF{sub 2} reflector, the epithermal neutron flux at the filter/moderator exit can reach {approx}8.5 x 10{sup 9} n/cm{sup 2}/s. When the collimator is added, the epithermal neutron beam intensity at the beam exit is reduced to 3 x 10{sup 9} n/cm{sup 2}/sec, but is still six times higher than the previous beam. Facing the clinical trials scheduled 3 and half years from now, a preliminary version of treatment planning system is developed. It includes a pre-processor to read CT scan and post-processors to display dose distributions. (author)

  9. In vitro biological effectiveness of JRR-4 epithermal neutron beam. Experiment under free air beam and in water phantom. Cooperative research

    Yamamoto, T; Horiguchi, Y; Kishi, T; Kumada, H; Matsumura, A; Nose, T; Torii, Y; Yamamoto, K


    The surviving curve and the biological effectiveness factor of dose components generated in boron neutron capture therapy (BNCT) were separately determined in neutron beams at Japan Research Reactor No.4. Surviving fraction of V79 Chinese hamster cell with or without sup 1 sup 0 B was obtained using an epithermal neutron beam (ENB), a mixed thermal-epithermal neutron beam (TNB-1), and a thermal neutron beam (TNB-2), which were used or planned to use for BNCT clinical trial. The cell killing effect of these neutron beams with or without the presence of sup 1 sup 0 B depended highly on the neutron beam used, according to the epithermal and fast neutron content in the beam. The biological effectiveness factor values of the boron capture reaction for ENB, TNB-1 and TNB-2 were 3.99+-0.24, 3.04+-0.19 and 1.43+-0.08, respectively. The biological effectiveness factor values of the high-LET dose components based on the hydrogen recoils and the nitrogen capture reaction were 2.50+-0.32, 2.34+-0.30 and 2.17+-0.28 for EN...

  10. 西安脉冲堆超热中子束的理论设计%Design of an Epithermal Neutron Beam for Xi'an Pulsed Reactor

    江新标; 陈达; 朱广宁; 麻江江; 郝金林


    The thermal column,which optimized by the three dimension diffusion model and corrected with the code MCNP/4B,is selected as the best duct for obtaining BNCT epithermal neutron beam.A conceptual design method for BNCT epithermal neutron beam has been performed.The method is used to analysis the properties of configuration materials of filter and advanced three schemes for thermal column reformed to epithermal neutron duct.%建立超热中子束孔道筛选的三维扩散模型,并用蒙特卡罗程序 MCNP/4B验证了热柱孔道是实现超热中子束的最佳孔道,还建立了硼中子俘获治疗 (BNCT)所需超热中子束的理论设计方法,对超热中子束过滤材料的特性进行了分析,提出了将西安脉冲堆热柱孔道改造成超热中子束孔道的 3种材料组合方案。

  11. Morphology, origin and infrared microthermometry of fluid inclusions in pyrite from the Radka epithermal copper deposit, Srednogorie zone, Bulgaria

    Kouzmanov, Kalin; Bailly, Laurent; Ramboz, Claire; Rouer, Olivier; Bény, Jean-Michel


    Pyrite samples from the Radka epithermal, replacement type, volcanic rock-hosted copper deposit, Bulgaria, have been studied using near-infrared (IR) microscopy. Two generations of pyrite based on their textures, composition and behaviour in IR light can be distinguished. Electron microprobe analyses, X-ray elemental mapping and Fourier transform infrared spectroscopy were used to study the relationship between crystal zoning, trace element contents and IR transmittance of pyrite. The observed crystal zoning is related to variable arsenic contents in massive fine-grained and colloform pyrite from the early pyrite-quartz assemblage, and cobalt contents in pyrite crystals from the late quartz-pyrite vein assemblage. There is a negative correlation between trace element content and IR transmittance of pyrite. The IR transparency of pyrite is thus a sensitive indicator of changes in trace element concentrations. Fluid inclusions have only been found in the second pyrite generation. Scanning electron microscopy observations on open fluid inclusion cavities permitted the crystallographic features of vacuoles to be determined. A characteristic feature of primary fluid inclusions in pyrite is a negative crystal habit, shaped mainly by {100}, {111} and {210}. This complicated polyhedral morphology is the reason for the observed opacity of some isometric primary inclusions. Secondary fluid inclusion morphology depends on the nature of the surface of the healed fracture. Recognition of the primary or secondary origin of fluid inclusions is enhanced by using crystallographically oriented sections. Microthermometric measurements of primary inclusions indicate that the second pyrite generation was deposited at maximum P-T conditions of 400 °C and 430 bar and from a fluid of low bulk salinity (3.5-4.6 wt%), possibly KCl-dominant. There are large ranges for homogenisation temperatures in secondary inclusions because of necking-down processes. Decrepitation features of some of

  12. Radiation injury of boron neutron capture therapy using mixed epithermal- and thermal neutron beams in patients with malignant glioma

    Kageji, T. E-mail:; Nagahiro, S.; Mizobuchi, Y.; Toi, H.; Nakagawa, Y.; Kumada, H


    The purpose of this study was to clarify the radiation injury in acute or delayed stage after boron neutron capture therapy (BNCT) using mixed epithermal- and thermal neutron beams in patients with malignant glioma. Eighteen patients with malignant glioma underwent mixed epithermal- and thermal neutron beam and sodium borocaptate between 1998 and 2004. The radiation dose (i.e. physical dose of boron n-alpha reaction) in the protocol used between 1998 and 2000 (Protocol A, n=8) prescribed a maximum tumor volume dose of 15 Gy. In 2001, a new dose-escalated protocol was introduced (Protocol B, n=4); it prescribes a minimum tumor volume dose of 18 Gy or, alternatively, a minimum target volume dose of 15 Gy. Since 2002, the radiation dose was reduced to 80-90% dose of Protocol B because of acute radiation injury. A new Protocol was applied to 6 glioblastoma patients (Protocol C, n=6). The average values of the maximum vascular dose of brain surface in Protocol A, B and C were 11.4{+-}4.2 Gy, 15.7{+-}1.2 and 13.9{+-}3.6 Gy, respectively. Acute radiation injury such as a generalized convulsion within 1 week after BNCT was recognized in three patients of Protocol B. Delayed radiation injury such as a neurological deterioration appeared 3-6 months after BNCT, and it was recognized in 1 patient in Protocol A, 5 patients in Protocol B. According to acute radiation injury, the maximum vascular dose was 15.8{+-}1.3 Gy in positive and was 12.6{+-}4.3 Gy in negative. There was no significant difference between them. According to the delayed radiation injury, the maximum vascular dose was 13.8{+-}3.8 Gy in positive and was 13.6{+-}4.9 Gy in negative. There was no significant difference between them. The dose escalation is limited because most patients in Protocol B suffered from acute radiation injury. We conclude that the maximum vascular dose does not exceed over 12 Gy to avoid the delayed radiation injury, especially, it should be limited under 10 Gy in the case that tumor

  13. Mineral resources of parts of the Departments of Antioquia and Caldas, Zone II, Colombia

    Hall, R.B.; Feininger, Tomas; Barrero, L.; Dario, Rico H.; ,; Alvarez, A.


    The mineral resources of an area of 40,000 sq km, principally in the Department of Antioquia, but including small parts of the Departments of Caldas, C6rdoba, Risaralda, and Tolima, were investigated during the period 1964-68. The area is designated Zone II by the Colombian Inventario Minero Nacional(lMN). The geology of approximately 45 percent of this area, or 18,000 sq km, has been mapped by IMN. Zone II has been a gold producer for centuries, and still produces 75 percent of Colombia's gold. Silver is recovered as a byproduct. Ferruginous laterites have been investigated as potential sources of iron ore but are not commercially exploitable. Nickeliferous laterite on serpentinite near Ure in the extreme northwest corner of the Zone is potentially exploitable, although less promising than similar laterites at Cerro Matoso, north of the Zone boundary. Known deposits of mercury, chromium, manganese, and copper are small and have limited economic potentia1. Cement raw materials are important among nonmetallic resources, and four companies are engaged in the manufacture of portland cement. The eastern half of Zone II contains large carbonate rock reserves, but poor accessibility is a handicap to greater development at present. Dolomite near Amalfi is quarried for the glass-making and other industries. Clay saprolite is abundant and widely used in making brick and tiles in backyard kilns. Kaolin of good quality near La Union is used by the ceramic industry. Subbituminous coal beds of Tertiary are an important resource in the western part of the zone and have good potential for greater development. Aggregate materials for construction are varied and abundant. Deposits of sodic feldspar, talc, decorative stone, and silica are exploited on a small scale. Chrysotils asbestos deposits north of Campamento are being developed to supply fiber for Colombia's thriving asbestos-cement industry, which is presently dependent upon imported fiber. Wollastonite and andalusite are

  14. Hydrothermal minerals

    Nath, B.N.

    -floor hydrothermal processes involving free circulation of seawater through ocean crust as convection. Heat flow, seafloor fracturing, permeability and fluid composition are the parameters governing the type and extent of mineralization. The chimney like... stream_size 23365 stream_content_type text/plain stream_name Refresher_Course_Mar_Geol_Geophys_2007_Lecture_Notes_78.pdf.txt stream_source_info Refresher_Course_Mar_Geol_Geophys_2007_Lecture_Notes_78.pdf.txt Content-Encoding UTF-8...

  15. Search for causes of the low epithermal neutron flux anomaly in the Arabia Terra region (Mars)

    Basilevsky, A. T.; Rodin, A. V.; Raitala, J.; Neukum, G.; Werner, S.; Kozyrev, A. S.; Sanin, A. B.; Mitrofanov, I. G.; Head, J. W.; Boynton, W.; Saunders, R. S.


    A geologic analysis of 274 images acquired by the high-resolution MOC camera onboard the Mars Global Surveyor spacecraft within the Arabia Terra low neutron flux anomaly (which is indicative of an anomalously high abundance of hydrogen: up to 16 wt % of the equivalent amount of water) was performed. Correlation between the enhanced abundance of equivalent water with the presence of dust on the surface was found. Since dust plays a key role in condensation of water from the atmosphere, we suppose that the anomalies could result from the retention of atmospheric moisture. To analyze this suggestion, we performed a theoretical modeling that allowed us to map the planetary-scale distributions of several meteorological parameters responsible for the atmospheric moisture condensation. Two antipodal regions coinciding rather well with the Arabia Terra anomaly and the geographically antipodal anomaly southwest of Olympus Mons were found in the maps. This suggests that the anomalies are rather recent than ancient formations. They were probably formed by a sink of moisture from the atmosphere in the areas where present meteorological conditions support this sink. Geological parameters, primarily the presence of dust, only promote this process. We cannot exclude the possibility that the Martian cryosphere, rather than the atmosphere, supplied the studied anomalies with moisture during their formation: the thermodynamic conditions in the anomaly areas could block the moisture flux from the Martian interior in the upper regolith layer. The moisture coming from the atmosphere or from the interior is likely held as chemically bound water entering into the structure of water-bearing minerals (probably, hydrated magnesium sulfates) directly from the vapor; or the moisture precipitates as frost, penetrates into microfissures, and then is bound in minerals. Probably, another geologic factor—the magnesium sulfate abundance—works in the Arabia Terra anomaly.

  16. The specific purpose Monte Carlo code McENL for simulating the response of epithermal neutron lifetime well logging tools

    Prettyman, T.H.; Gardner, R.P.; Verghese, K. (North Carolina State Univ., Raleigh, NC (United States). Center for Engineering Applications and Radioisotopes)


    A new specific purpose Monte Carlo code called McENL for modeling the time response of epithermal neutron lifetime tools is described. The code was developed so that the Monte Carlo neophyte can easily use it. A minimum amount of input preparation is required and specified fixed values of the parameters used to control the code operation can be used. The weight windows technique, employing splitting and Russian Roulette, is used with an automated importance function based on the solution of an adjoint diffusion model to improve the code efficiency. Complete composition and density correlated sampling is also included in the code and can be used to study the effect on tool response of small variations in the formation, borehole, or logging tool composition and density. An illustration of the latter application is given here for the density of a thermal neutron filter. McENL was benchmarked against test-pit data for the Mobil pulsed neutron porosity (PNP) tool and found to be very accurate. Results of the experimental validation and details of code performance are presented.

  17. Study of the relative dose-response of BANG-3® polymer gel dosimeters in epithermal neutron irradiation

    Uusi-Simola, J.; Savolainen, S.; Kangasmäki, A.; Heikkinen, S.; Perkiö, J.; Abo Ramadan, U.; Seppälä, T.; Karila, J.; Serén, T.; Kotiluoto, P.; Sorvari, P.; Auterinen, I.


    Polymer gels have been reported as a new, potential tool for dosimetry in mixed neutron-gamma radiation fields. In this work, BANG-3 (MGS Research Inc.) gel vials from three production batches were irradiated with 6 MV photons of a Varian Clinac 2100 C linear accelerator and with the epithermal neutron beam of the Finnish boron neutron capture therapy (BNCT) facility at the FiR 1 nuclear reactor. The gel is tissue equivalent in main elemental composition and density and its T2 relaxation time is dependent on the absorbed dose. The T2 relaxation time map of the irradiated gel vials was measured with a 1.5 T magnetic resonance (MR) scanner using spin echo sequence. The absorbed doses of neutron irradiation were calculated using DORT computer code, and the accuracy of the calculational model was verified by measuring gamma ray dose rate with thermoluminescent dosimeters and 55Mn(n,gamma) activation reaction rate with activation detectors. The response of the BANG-3 gel dosimeter for total absorbed dose in the neutron irradiation was linear, and the magnitude of the response relative to the response in the photon irradiation was observed to vary between different gel batches. The results support the potential of polymer gels in BNCT dosimetry, especially for the verification of two- or three-dimensional dose distributions.

  18. Self-Ordering and Complexity in Epizonal Mineral Deposits

    Henley, Richard W.; Berger, Byron R.

    Epizonal base and precious metal deposits makeup a range of familiar deposit styles including porphyry copper-gold, epithermal veins and stockworks, carbonate-replacement deposits, and polymetallic volcanic rock-hosted (VHMS) deposits. They occur along convergent plate margins and are invariably associated directly with active faults and volcanism. They are complex in form, variable in their characteristics at all scales, and highly localized in the earth's crust. More than a century of detailed research has provided an extensive base of observational data characterizing these deposits, from their regional setting to the fluid and isotope chemistry of mineral deposition. This has led to a broad understanding of the large-scale hydrothermal systems within which they form. Low salinity vapor, released by magma crystallization and dispersed into vigorously convecting groundwater systems, is recognized as a principal source of metals and the gases that control redox conditions within systems. The temperature and pressure of the ambient fluid anywhere within these systems is close to its vapor-liquid phase boundary, and mineral deposition is a consequence of short timescale perturbations generated by localized release of crustal stress. However, a review of occurrence data raises questions about ore formation that are not addressed by traditional genetic models. For example, what are the origins of banding in epithermal veins, and what controls the frequency of oscillatory lamination? What controls where the phenomenon of mineralization occurs, and why are some porphyry deposits, for example, so much larger than others? The distinctive, self-organized characteristics of epizonal deposits are shown to be the result of repetitive coupling of fracture dilation consequent on brittle failure, phase separation ("boiling"), and heat transfer between fluid and host rock. Process coupling substantially increases solute concentrations and triggers fast, far

  19. Minerals Yearbook, volume I, Metals and Minerals



    The U.S. Geological Survey (USGS) Minerals Yearbook discusses the performance of the worldwide minerals and materials industries and provides background information to assist in interpreting that performance. Content of the individual Minerals Yearbook volumes follows:Volume I, Metals and Minerals, contains chapters about virtually all metallic and industrial mineral commodities important to the U.S. economy. Chapters on survey methods, summary statistics for domestic nonfuel minerals, and trends in mining and quarrying in the metals and industrial mineral industries in the United States are also included.Volume II, Area Reports: Domestic, contains a chapter on the mineral industry of each of the 50 States and Puerto Rico and the Administered Islands. This volume also has chapters on survey methods and summary statistics of domestic nonfuel minerals.Volume III, Area Reports: International, is published as four separate reports. These regional reports contain the latest available minerals data on more than 180 foreign countries and discuss the importance of minerals to the economies of these nations and the United States. Each report begins with an overview of the region’s mineral industries during the year. It continues with individual country chapters that examine the mining, refining, processing, and use of minerals in each country of the region and how each country’s mineral industry relates to U.S. industry. Most chapters include production tables and industry structure tables, information about Government policies and programs that affect the country’s mineral industry, and an outlook section.The USGS continually strives to improve the value of its publications to users. Constructive comments and suggestions by readers of the Minerals Yearbook are welcomed.

  20. The improvement of the energy resolution in epi-thermal neutron region of Bonner sphere using boric acid water solution moderator.

    Ueda, H; Tanaka, H; Sakurai, Y


    Bonner sphere is useful to evaluate the neutron spectrum in detail. We are improving the energy resolution in epi-thermal neutron region of Bonner sphere, using boric acid water solution as a moderator. Its response function peak is narrower than that for polyethylene moderator and the improvement of the resolution is expected. The resolutions between polyethylene moderator and boric acid water solution moderator were compared by simulation calculation. Also the influence in the uncertainty of Bonner sphere configuration to spectrum estimation was simulated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Reprint of The improvement of the energy resolution in epi-thermal neutron region of Bonner sphere using boric acid water solution moderator.

    Ueda, H; Tanaka, H; Sakurai, Y


    Bonner sphere is useful to evaluate the neutron spectrum in detail. We are improving the energy resolution in epi-thermal neutron region of Bonner sphere, using boric acid water solution as a moderator. Its response function peak is narrower than that for polyethylene moderator and the improvement of the resolution is expected. The resolutions between polyethylene moderator and boric acid water solution moderator were compared by simulation calculation. Also the influence in the uncertainty of Bonner sphere configuration to spectrum estimation was simulated.

  2. Miscellaneous Industrial Mineral Operations

    Department of Homeland Security — This map layer includes miscellaneous industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team...

  3. Ordovician Intrusive-related Gold-Copper Mineralization in West-Central New South Wales, Australia


    Three major types of Ordovician intrusive-related gold-copper deposits are recognized in central-west New South Wales,, Australia: porphyry, skam and high sulphidation epithermal deposits.These deposits are mainly distributed within two Ordovician volcano-intrusive belts of the Lachlan Fold Be1t: the Orange-Wellington Belt and the Parkes-Narromine Belt. Available isotopic age data suggest that mineralization of the three types of deposits is essentially coeval with the Ordovician intrusive rocks (480-430 Ma). Porphyry gold-copper deposits can be further divided into two groups. The first group is associated with monzoniteshowing shoshonitic features represented by Cadia and Goonumbla. The second group is associated with diorite and dacite, including the Copper Hill and Cargo gold-copper deposits. Gold skarn is associated with Late Ordovician (430-439 Ma) monzonitic intrusive complexes in the Junction Reefs area (Sheahan-Grants, Frenchmans, and Cornishmens), Endeavour 6, 7 and 44, Big and Little Cadia. The epithermal gold deposits with high sulphidation including Gidginbung (Temora) and Peak Hill mainly occur within Ordovician andesite and volcaniclastic rocks, and are associated with advanced argillic alteration. Available isotopic age data indicate that both alteration and mineralization of the porphyry, skam and epithermal gold-copper deposits are broadly coeval with the Late Ordovician hoshonitic mangmatism, which is thought to result from the melting of sub-continental lithosphere caused by Palaeozoic subduction events. The Ordovician intrusive-related gold-copper deposits are restricted to two longitudinal parallel volcano-intrusive belts, rarely extending outside them. Diagonal intra-belt trends of mineralization are common, particularly at the intersections of longitudinal and transverse (oblique) fault/fracture zones basedon the authors'review of available geological data. The locations of these gold-copper deposits are obviously influenced by transverse

  4. Preliminary Design of LEU MNSR for BNCT with Excellent Epithermal Neutron Flux Treatment Beam%高额超热中子束流治疗孔道低浓化BNCT堆初步设计方案

    于涛; 钱金栋; 谢金森


    Based on the Miniature Neutron Source Reactor (MNSR) with high enrichment uranium (HEU) fuel and accordance with the requirements of BNCT, the 19.5% of enriched fuel UO2 fuel core for BNCT with epithermal neutron treatment beam was primary designed, the reactor core parameters such as epithermal neutron flux density,epithermal neutron flux unit of fast neutron dose rate,epithermal neutron flux unit photon dose rate of γ,epithermal neutron flux ratio of thermal neutron flux, neutron spectrum were calculated and analyzed. The results show that the design program was an excellent epithermal neutron treatment beam.%根据硼中子俘获治疗( BNCT)中子源的要求,在高浓铀为燃料的微型反应堆(MNSR)的基础上,以富集度19.5%的UO2为燃料,将其堆芯低浓化并且添加水平超热中子束流治疗孔道,开展超热中子束流BNCT堆堆芯低浓化初步设计.计算BNCT堆的超热中子注量率、单位超热中子注量的快中子剂量率、单位超热中子注量的γ光子剂量率、超热中子注量与热中子的注量之比、中子束流能谱等关键参数.结果表明,该设计可以得到优良的超热中子束流.

  5. Constraints on Hf and Zr mobility in high-sulfidation epithermal systems: formation of kosnarite, KZr2(PO4)3, in the Chaquicocha gold deposit, Yanacocha district, Peru

    Deditius, Artur P.; Utsunomiya, Satoshi; Sanchez-Alfaro, Pablo; Reich, Martin; Ewing, Rodney C.; Kesler, Stephen E.


    We report the first occurrence of Hf-rich kosnarite [K(Hf,Zr)2(PO4)3], space group R- 3c, Z = 6, in the giant Chaquicocha high-sulfidation epithermal gold deposit in the Yanacocha mining district, Peru. Kosnarite crystals are small (Yanacocha is indicative of Hf and Zr mobility under highly acidic conditions and points towards an unforeseen role of phosphates as sinks of Zr and Hf in high-sulfidation epithermal environments. Finally, potentially new geochronological applications of highly insoluble vein kosnarite, including Rb-Sr dating, may provide further age constraints in pervasively altered areas where other isotopic systems might have been reset.

  6. Determinants of pathologic mineralization.

    Kirsch, Thorsten


    Physiologic mineralization is necessary for the formation of skeletal tissues and for their appropriate functions during adulthood. Mineralization has to be controlled and restricted to specific regions. If the mineralization process occurs in regions that normally do not mineralize, there can be severe consequences (pathologic or ectopic mineralization). Recent findings have indicated that physiologic and pathologic mineralization events are initiated by matrix vesicles, membrane-enclosed particles released from the plasma membranes of mineralization-competent cells. The understanding of how these vesicles are released from the plasma membrane and initiate the mineralization process may provide novel therapeutic strategies to prevent pathologic mineralization. In addition, other regulators (activators and inhibitors) of physiologic mineralization have been identified and characterized, and there is evidence that the same factors also contribute to the regulation of pathologic mineralization. Finally, programmed cell death (apoptosis) may be a contributor to physiologic mineralization and if occurring after tissue injury may induce pathologic mineralization and mineralization-related differentiation events in the injured and surrounding areas. This review describes how the understanding of mechanisms and factors regulating physiologic mineralization can be used to develop new therapeutic strategies to prevent pathologic or ectopic mineralization events.

  7. Boron neutron capture therapy for glioblastoma multiforme using p-boronophenylalanine and epithermal neutrons: trial design and early clinical results.

    Coderre, J A; Elowitz, E H; Chadha, M; Bergland, R; Capala, J; Joel, D D; Liu, H B; Slatkin, D N; Chanana, A D


    A Phase I/II clinical trial of boron neutron capture therapy (BNCT) for glioblastoma multiforme is underway using the amino acid analog p-boronophenylalanine (BPA) and the epithermal neutron beam at the Brook-haven Medical Research Reactor. Biodistribution studies were carried out in 18 patients at the time of craniotomy using an i.v. infusion of BPA, solubilized as a fructose complex (BPA-F). There were no toxic effects related to the BPA-F administration at doses of 130, 170, 210, or 250 mg BPA/kg body weight. The tumor/ blood, brain/blood and scalp/blood boron concentration ratios were approximately 3.5:1, 1:1 and 1.5:1, respectively. Ten patients have received BNCT following 2-hr infusions of 250 mg BPA/kg body weight. The average boron concentration in the blood during the irradiation was 13.0 +/- 1.5 micrograms 10B/g. The prescribed maximum dose to normal brain (1 cm3 volume) was 10.5 photon-equivalent Gy (Gy-Eq). Estimated maximum and minimum doses (mean +/- sd, n = 10) to the tumor volume were 52.6 +/- 4.9 Gy-Eq (range: 64.4-47.6) and 25.2 +/- 4.2 Gy-Eq (range: 32.3-20.0), respectively). The estimated minimum dose to the target volume (tumor +2 cm margin) was 12.3 +/- 2.7 Gy-Eq (range: 16.2-7.8). There were no adverse effects on normal brain. The scalp showed mild erythema, followed by epilation in the 8 cm diameter field. Four patients developed recurrent tumor, apparently in the lower dose (deeper) regions of the target volume, at post-BNCT intervals of 7,5,3.5 and 3 months, respectively. The remaining patients have had less than 4 months of post-BNCT follow-up. BNCT, at this starting dose level, appears safe. Plans are underway to begin the dose escalation phase of this protocol.

  8. Exploration of Adiabatic Resonance Crossing Through Neutron Activator Design for Thermal and Epithermal Neutron Formation in (99)Mo Production and BNCT Applications.

    Khorshidi, Abdollah


    A feasibility study was performed to design thermal and epithermal neutron sources for radioisotope production and boron neutron capture therapy (BNCT) by moderating fast neutrons. The neutrons were emitted from the reaction between (9)Be, (181)Ta, and (184)W targets and 30 MeV protons accelerated by a small cyclotron at 300 μA. In this study, the adiabatic resonance crossing (ARC) method was investigated by means of (207)Pb and (208)Pb moderators, graphite reflector, and boron absorber around the moderator region. Thermal/epithermal flux, energy, and cross section of accumulated neutrons in the activator were examined through diverse thicknesses of the specified regions. Simulation results revealed that the (181)Ta target had the highest neutron yield, and also tungsten was found to have the highest values in both surface and volumetric flux ratio. Transmutation in the (98)Mo sample through radiative capture was investigated for the natural lead moderator. When the sample radial distance from the target was increased inside the graphite region, the production yield had the greatest value of activity. The potential of the ARC method is a replacement or complements the current reactor-based supply sources of BNCT purposes.

  9. Improvement of dose distribution in phantom by using epithermal neutron source based on the Be(p,n) reaction using a 30 MeV proton cyclotron accelerator.

    Tanaka, H; Sakurai, Y; Suzuki, M; Takata, T; Masunaga, S; Kinashi, Y; Kashino, G; Liu, Y; Mitsumoto, T; Yajima, S; Tsutsui, H; Takada, M; Maruhashi, A; Ono, K


    In order to generate epithermal neutrons for boron neutron capture therapy (BNCT), we proposed the method of filtering and moderating fast neutrons, which are emitted from the reaction between a beryllium target and 30 MeV protons accelerated by a cyclotron, using an optimum moderator system composed of iron, lead, aluminum, calcium fluoride, and enriched (6)LiF ceramic filter. At present, the epithermal-neutron source is under construction since June 2008 at Kyoto University Research Reactor Institute. This system consists of a cyclotron to supply a proton beam of about 1 mA at 30 MeV, a beam transport system, a beam scanner system for heat reduction on the beryllium target, a target cooling system, a beam shaping assembly, and an irradiation bed for patients. In this article, an overview of the cyclotron-based neutron source (CBNS) and the properties of the treatment neutron beam optimized by using the MCNPX Monte Carlo code are presented. The distribution of the RBE (relative biological effectiveness) dose in a phantom shows that, assuming a (10)B concentration of 13 ppm for normal tissue, this beam could be employed to treat a patient with an irradiation time less than 30 min and a dose less than 12.5 Gy-eq to normal tissue. The CBNS might be an alternative to the reactor-based neutron sources for BNCT treatments.

  10. Hydrothermal Evolution of the Giant Cenozoic Kadjaran porphyry Cu-Mo deposit, Tethyan metallogenic belt, Armenia, Lesser Caucasus: mineral paragenetic, cathodoluminescence and fluid inclusion constraints

    Hovakimyan, Samvel; Moritz, Robert; Tayan, Rodrik; Rezeau, Hervé


    The Lesser Caucasus belongs to the Central segment of the Tethyan metallogenic belt and it is a key area to understand the metallogenic evolution between the Western & Central parts of the Tethyan belt and its extension into Iran. Zangezur is the most important mineral district in the southernmost Lesser Caucasus. It is a component of the South Armenian block, and it was generated during the convergence and collision of the southern margin of the Eurasian plate and the northern margin of the Arabian plate, and terranes of Gondwana origin (Moritz et al., in press). The Zangezur ore district consists of the Tertiary Meghri-Ordubad composite pluton, which is characterized by a long-lasting Eocene to Pliocene magmatic, tectonic and metallogenic evolution. It hosts major porphyries Cu-Mo and epithermal Au - polymetallic deposits and occurrences, including the giant world class Kadjaran porphyry Cu-Mo deposit (2244 Mt reserves, 0.3% Cu, 0.05% Mo and 0.02 g/t Au). The Kadjaran deposit is hosted by a monzonite intrusion (31.83±0.02Ma; Moritz et al., in press). Detailed field studies of the porphyry stockwork and veins of the different mineralization stages, their crosscutting and displacement relationships and the age relationship between different paragenetic mineral associations were the criteria for distinction of the main stages of porphyry mineralization at the Kadjaran deposit. The economic stages being: quartz- molybdenite, quartz-molybdenite-chalcopyrite, and quartz-chalcopyrite. The main paragenetic association of the Kadjaran porphyry deposit includes pyrite, molybdenite, chalcopyrite, bornite, chalcocite, pyrrhotite, covellite, sphalerite, and galena. Recent field observations in the Kadjaran open pit revealed the presence of epithermal veins with late vuggy silica and advanced argillic alteration in the north-eastern and eastern parts of the deposit. They are distributed as separate veins and have also been recognized in re-opened porphyry veins and in

  11. ASTER, ALI and Hyperion sensors data for lithological mapping and ore minerals exploration.

    Beiranvand Pour, Amin; Hashim, Mazlan


    This paper provides a review of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Land Imager (ALI), and Hyperion data and applications of the data as a tool for ore minerals exploration, lithological and structural mapping. Spectral information extraction from ASTER, ALI, and Hyperion data has great ability to assist geologists in all disciplines to map the distribution and detect the rock units exposed at the earth's surface. The near coincidence of Earth Observing System (EOS)/Terra and Earth Observing One (EO-1) platforms allows acquiring ASTER, ALI, and Hyperion imagery of the same ground areas, resulting accurate information for geological mapping applications especially in the reconnaissance stages of hydrothermal copper and gold exploration, chromite, magnetite, massive sulfide and uranium ore deposits, mineral components of soils and structural interpretation at both regional and district scales. Shortwave length infrared and thermal infrared bands of ASTER have sufficient spectral resolution to map fundamental absorptions of hydroxyl mineral groups and silica and carbonate minerals for regional mapping purposes. Ferric-iron bearing minerals can be discriminated using six unique wavelength bands of ALI spanning the visible and near infrared. Hyperion visible and near infrared bands (0.4 to 1.0 μm) and shortwave infrared bands (0.9 to 2.5 μm) allowed to produce image maps of iron oxide minerals, hydroxyl-bearing minerals, sulfates and carbonates in association with hydrothermal alteration assemblages, respectively. The techniques and achievements reviewed in the present paper can further introduce the efficacy of ASTER, ALI, and Hyperion data for future mineral and lithological mapping and exploration of the porphyry copper, epithermal gold, chromite, magnetite, massive sulfide and uranium ore deposits especially in arid and semi-arid territory.

  12. Late Cretaceous structural control and Alpine overprint of the high-sulfidation Cu-Au epithermal Chelopech deposit, Srednogorie belt, Bulgaria

    Chambefort, Isabelle; Moritz, Robert


    The Chelopech epithermal high-sulfidation deposit is located in the Panagyurishte ore district in Bulgaria, which is defined by a NNW alignment of Upper Cretaceous porphyry-Cu and Cu-Au epithermal deposits, and forms part of the Eastern European Banat-Srednogorie belt. Detailed structural mapping and drillcore descriptions have been used to define the structural evolution of the Chelopech deposit from the Late Cretaceous to the present. The Chelopech deposit is characterized by three fault populations including ˜N55, ˜N110, and ˜N155-trending faults, which are also recognized in the entire Panagyurishte district. Mapping and 3-D modeling show that hydrothermal alteration and orebody geometry at Chelopech are controlled by the ˜N55-trending and ˜N110-trending faults. Moreover, the ˜N155-trending faults are parallel to the regional ore deposit alignment of the Panagyurishte ore district. It is concluded that the three fault populations are early features and Late Cretaceous in age, and that they were active during high-sulfidation ore formation at Chelopech. However, the relative fault chronology cannot be deduced anymore due to Late Cretaceous and Tertiary tectonic overprint. Structurally controlled ore formation was followed by Senonian sandstone, limestone, and flysch deposition. The entire Late Cretaceous magmatic and sedimentary rock succession underwent folding, which produced WNW-oriented folds throughout the Panagyurishte district. A subsequent tectonic stage resulted in overthrusting of older rock units along ˜NE-trending reverse faults on the Upper Cretaceous magmatic and sedimentary host rocks of the high-sulfidation epithermal deposit at Chelopech. The three fault populations contemporaneous with ore formation, i.e., the ˜N55-, ˜N110- and ˜N155-trending faults, were reactivated as thrusts or reverse faults, dextral strike-slip faults, and transfer faults, respectively, during this event. Previous studies indicate that the present-day setting is

  13. A review of mineral systems and associated tectonic settings of northern Xinjiang, NW China

    Franco Pirajno


    Full Text Available In this paper we present a review of mineral systems in northern Xinjiang, NW China, focussing on the Tianshan, West and East Junggar and Altay orogenic belts, all of which are part of the greater Central Asian Orogenic Belt (CAOB. The CAOB is a complex collage of ancient microcontinents, island arcs, oceanic plateaux and oceanic plates, which were amalgamated and accreted in Early Palaeozoic to Early Permian times. The establishment of the CAOB collage was followed by strike-slip movements and affected by intraplate magmatism, linked to mantle plume activity, best exemplified by the 250 Ma Siberian Traps and the 280 Ma Tarim event. In northern Xinjiang, there are numerous and economically important mineral systems. In this contribution we describe a selection of representative mineral deposits, including subduction-related porphyry and epithermal deposits, volcanogenic massive sulphides and skarn systems. Shear zone-hosted Au lodes may have first formed as intrusion-related and subsequently re-worked during strike-slip deformation. Intraplate magmatism led to the emplacement of concentrically zoned (Alaskan-style mafic–ultramafic intrusions, many of which host orthomagmatic sulphide deposits. A huge belt of pegmatites in the Altay orogen, locally hosts world-class rare metal deposits. Roll-front, sandstone-hosted U mineralisation completes the rich mineral endowment of the northern Xinjiang terranes.

  14. Mineral resources of Australia

    Kelsall, D.F.; Woodcock, J.T. (eds.)


    The papers presented cover geological, geochemical technology and geophysics in mineral exploration, mineral resources, mining methods and technology, aspects of beneficiation, pyrometallurgy and hydrometallurgy, and environmental aspects. 4 of the 14 papers have been abstracted separately.

  15. Construction Minerals Operations

    Department of Homeland Security — This map layer includes construction minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  16. Agricultural Minerals Operations

    Department of Homeland Security — This map layer includes agricultural minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  17. Mineral Resources Data System

    U.S. Geological Survey, Department of the Interior — Mineral resource occurrence data covering the world, most thoroughly within the U.S. This database contains the records previously provided in the Mineral Resource...

  18. Mineral Supply Challenges


    Faced with shortcomings in its mineral supply, it’s imperative for China to balance its desire for reserves with its current economic needs Mineral resources are the corner- stone of materials needed for China’s national economic and social development.The country even counts on its mineral resources to satisfy 90 percent of its energy demands and over 95

  19. The geology of aluminium phosphates and sulphates of the alunite group minerals: a review

    Dill, Harald G.


    Aluminium phosphates and sulphates of the alunite supergroup (APS minerals) occur in a wide range of environments of formation covering the metamorphic, igneous and sedimentary realms. Supergene processes, including mineral dressing and dumping when sulphide ores are mined, as well as hypogene alteration are also responsible for the precipitation of APS minerals. In these environments, complex solid solution series (s.s.s.) can form. The general formula of these alunite minerals is AB 3 (XO 4) 2(OH) 6, where A is a large cation (Na, U, K, Ag, NH 4, Pb, Ca, Ba, Sr, REE). B sites are occupied by cations of the elements Al, Fe, Cu and Zn. In nature, the anion (XO 4) x- is dominated by P and S. Mineral dressing and identification of APS minerals often needs a combination of highly sophisticated measures including Atterberg settling methods, XRD, DTA, TGA, TEM-EDX, SEM, EMPA and XRF. In sedimentary rocks APS minerals occur in various rocks and environments of deposition: calcareous, phosphorite-bearing, argillaceous-carbonaceous, arenaceous, coal-bearing environments, in soils and paleosols, in saprolite (bauxites, laterites) and in calcareous-argillaceous sequences hosting Carlin-type SHDG deposits. In igneous rocks, APS minerals may be encountered mainly in acidic through intermediate pyroclastic, volcanic and subvolcanic rocks. They occur in barren volcanic rocks and porphyry-type intrusions that have sparked epithermal Au-Ag-base metal deposits, Au-Sb mineralization, APS-bearing argillite and alunite deposits in their immediate surroundings. Granitic and pegmatitic rocks are rarely host of supergene APS mineralization. During low-grade stage regional metamorphism, peraluminous parent rocks originating from a sedimentary or igneous protolith may also give rise to APS mineralization. Peraluminous parent rocks enriched in S and/or P are a prerequisite for the formation of APS minerals that are stable up to a temperature of 400°C at moderately high fluid pressure of up

  20. Manganese mineralization in andesites of Brestovačka Banja, Serbia: evidence of sea-floor exhalations in the Timok Magmatic Complex

    Pačevski, Aleksandar; Cvetković, Vladica; Šarić, Kristina; Banješević, Miodrag; Hoefer, Heidi Eva; Kremenović, Aleksandar


    Andesites near Brestovačka Banja belong to the Late Cretaceous Timok Magmatic Complex (TMC), which hosts the world-class Bor metallogenic zone including numerous porphyry-copper and epithermal deposits. Two main volcanic phases are recognized in the TMC. The newly discovered Mn mineralization reported here is associated with the second volcanic phase of Turonian-Campanian age. Manganese mineralization containing 58 % MnO on average, occurs as black veins, lumps and nests filling cracks and cavities within an autoclastic andesite, which was deposited in a subaqueous environment. This rock also contains minor Fe mineralization, which is contemporaneous with the manganese mineralization. Manganese mineralization predominantly consists of Mn-Ca silicates (macfallite, pumpellyite-Mn, orientite, bustamite) and Mn oxides (pyrolusite, manganite). Micrometer-scale mineral intergrowths and locally preserved botryoidal and colloform textures are characteristic features of this uncommon mineral assemblage. The features could indicate that the mineralization was formed by deposition from a primary colloidal assemblage and is of sub-marine hydrothermal origin. Orientite is the only Mn mineral with grain size reaching several tenths of micrometers and showing prismatic crystal habit. Scarce to rare associated minerals are hollandite, crednerite, an unknown REE mineral, powellite, pyrite, barite and galena, in decreasing abundance. Trace element analyses of the Mn mineralization show different element contents and REE patterns compared to those of the volcanic host-rock. Manganese mineralization shows relatively high contents of Cu - 1784 ppm, Mo - 20 ppm and As - 268 ppm. These elements are commonly enriched in the Cu deposits of the Bor zone and their relatively high contents in the studied Mn crusts indicate sea-floor hydrothermal vents as a source of the metals.

  1. Different Activation Techniques for the Study of Epithermal Spectra, Applied to Heavy Water Lattices of Varying Fuel-To-Moderator Ratio

    Sokolowski, E.K.


    Spectral indices at the cell boundary have been studied as functions of lattice pitch in the reference core of the Swedish R0 reactor. Epithermal indices were determined by activation of In{sup 115}, employing three different techniques: the two-foil, the cadmium ratio and the sandwich foil methods. The latter of these has the advantage of being independent of assumptions about foil cross sections or spectral functions, and it gives a spectrum index that lends itself readily to comparisons with theoretical multigroup calculations. Alternatively the results can be expressed in terms of the Westcott parameters r and T{sub n} when this is justified by the spectral conditions. The agreement between the three methods investigated is generally good. Good agreement is also found with multigroup collision.

  2. Mineral resources and exploration prospect in The Republic of Yemen%也门共和国矿产资源与矿业开发前景

    李娜; 王靓靓; 元春华; 李玉龙


    也门共和国地处阿拉伯-努比亚(Arabian-Nubian)地盾,地质结构复杂多样,在火山岩和沉积岩区蕴藏着丰富的黄金、铅、银、铜、锌和其他金属矿产。也门的金矿主要位于Sana'a省,与火山和岩浆活动有关;铅锌矿成因类型较复杂,最大的铅锌矿产出于JabalSalab地区侏罗纪的白云岩中;铜镍矿存在于基性、超基性的侵入岩中,主要位于Taiz和Amran省。也门矿产资源丰富但大量矿床尚未被开发,有巨大的找矿潜力。本文结合也门矿产的资源情况及矿业开发现状圈定了优势矿产的找矿远景区,如Al Jawf省西部的金-银矿远景区,Sa'ada省北部的铜-镍矿远景区,以及Shabwah省东南部的锌-铅矿远景区等。也门共和国矿产资源丰富,矿业及税收政策宽松,定会成为未来矿业投资的热点区域。%The Republic of Yemen composes part of the Arabian -Nubian Shield .The geological conditions in Yemen and other factors are favourable for many types of mineral deposits ,like gold ,lead , silver ,copper and zinc .The gold deposit located in Sana'a is related to volcanic and magma activity ;the genetic type of lead-zinc deposit is complicated and the biggest deposit appeared in dolomite of Jurassic in JabalSalab region;copper-nickel deposit is located in Taiz and Amran ,in mafic and ultra-mafic intrusive rocks .The mineral potential of Yemen has not been explored .By analysing the mineral resource distribution and the current mineral exploration situation ,the author defined several prospect zones ,like Al Jawf for gold-silver deposit ,Sa'ada for copper-nickel deposit ,and Shabwah for zinc-lead deposits .With favourable mining and fax policy ,The Republic of Yemen will abstract more oversee investment and to be a hot spot for mineral exploration in the future .

  3. Chelated minerals for poultry

    SL Vieira


    Full Text Available Organic minerals have been subject of an increasing number of investigations recently. These compounds can be considered the most significant event regarding commercial forms of minerals targeting animal supplementation in the last decades. Minerals, especially metals, are usually supplemented in poultry feeds using cheap saline sources and have never required a lot of attention in terms of quality. On the other hand, definitions of organic minerals are very broad and frequently lead to confusion when decision-making becomes necessary. Organic minerals include any mineral bound to organic compounds, regardless of the type of existing bond between mineral and organic molecules. Proteins and carbohydrates are the most frequent candidates in organic mineral combinations. Organic fraction size and bond type are not limitations in organic mineral definition; however, essential metals (Cu, Fe, Zn, and Mn can form coordinated bonds, which are stable in intestinal lumen. Metals bound to organic ligands by coordinated bonds can dissociate within animal metabolism whereas real covalent bonds cannot. Chelated minerals are molecules that have a metal bound to an organic ligand through coordinated bonds; but many organic minerals are not chelates or are not even bound through coordinated bonds. Utilization of organic minerals is largely dependent on the ligand; therefore, amino acids and other small molecules with facilitated access to the enterocyte are supposed to be better utilized by animals. Organic minerals with ligands presenting long chains may require digestion prior to absorption. After absorption, organic minerals may present physiological effects, which improve specific metabolic responses, such as the immune response. Many studies have demonstrated the benefits of metal-amino acid chelates on animal metabolism, but the detection positive effects on live performance is less consistent.

  4. 43 CFR 19.8 - Prospecting, mineral locations, mineral patents, and mineral leasing within National Forest...


    ... patents, and mineral leasing within National Forest Wilderness. 19.8 Section 19.8 Public Lands: Interior... § 19.8 Prospecting, mineral locations, mineral patents, and mineral leasing within National Forest... locations, mineral patents, and mineral leasing within National Forest Wilderness are contained in parts...

  5. Form of Occurrence and Distribution Law of Associated Gold(Silver)in Anhui Tongling Huashupo Copper Mine%安徽铜陵桦树坡铜矿床伴生金(银)赋存状态及分布规律

    陈耀远; 周贵斌


    Huashupo copper ore deposit is controlled skam-type. By thin section authentication and electron probe microanalyais, the ore deposit's mineral species are not much, trace mineral species are much. They are mainly chalcopyrite, pyrrhotite, pyrite, and gold and silver, native bismuth. The study of process mineralogy is made, and finds out the form of occurrence and process nature, providing reference for reasonably determining preparing process and conditions.%桦树坡铜矿床为一层控式矽卡岩型铜矿床,经光薄片鉴定及电子探针分析,该矿床主要矿物种类不多,而微量矿物种类较多,主要矿物有为黄铜矿、磁黄铁矿、黄铁矿,自然元素为金—银系列矿物及自然铋等.对该铜矿进行了工艺矿物学研究,重点查明了伴生金银的赋存状态及工艺性质.为伴生金银回收确定合理选矿工艺流程及条件提供依据.

  6. Anhydrite-bearing andesite and dacite as a source for sulfur in magmatic-hydrothermal mineral deposits

    Chambefort, Isabelle; Dilles, John H.; Kent, Adam J. R.


    Magmaticanhydritefromandesitesanddacitesoccursasinclusionsinhigh-andlow-aluminumamphibole and pyroxene and indicates that sulfate-saturatedmagmas spanned a period of six million years at Yanacocha, Peru.Magmatic anhydrite from Yanacocha and other sites is characterizedby light rare earth element-enriched patterns and elevatedstrontium contents distinct from magmatic-hydrothermal anhydrite.Petrologic arguments suggest that the hydrous and oxidized Yanacochamagmas contained more than ~1000 ppm sulfur both dissolved inthe melt and as a separate sulfate phase, which is sufficientto provide all the sulfur for the genetically related giantsulfur-rich Yanacocha epithermal gold deposits. High-aluminumamphiboles contain unusual anhydrite with wormy and amoeboidaltextures, which are tentatively interpreted to represent trappingof an immiscible CaSO4-water melt together with sulfur-richapatite at a temperature of ~950 °C and a water pressure>3 kbar. Such unusually sulfate-rich magmas may be requiredto produce sulfur-rich magmatic-hydrothermal mineral deposits.

  7. Regional and local controls on mineralization and pluton emplacement in the Bondy gneiss complex, Grenville Province, Canada interpreted from aeromagnetic and gravity data

    Dufréchou, G.; Harris, L. B.; Corriveau, L.; Antonoff, V.


    The Bondy gneiss complex in the Grenville Province of Southwest Quebec hosts a mineralized iron oxide- and copper-rich hydrothermal system. The northern part of the complex overlies the lithospheric-scale Mont-Laurier lineament and is cut by the regional Mont-Laurier South shear zone interpreted from Bouguer gravity. A sinistral 6 km wide strike-slip corridor defined by several second-order shears (the Mont-Laurier South shear zone) in the complex was identified from geophysical data, including a new high-resolution airborne magnetic survey, and field observations. The spatial association of a metamorphosed alteration system, several pre- to post-metamorphic mineralized zones and mafic intrusions within the Mont-Laurier South shear zone suggests that (i) underlying basement structures controlled hydrothermal fluid migration during the formation of epithermal-IOCG mineralization and associated alteration system before ca. 1.2 Ga high-grade metamorphism and penetrative ductile deformation in the complex; (ii) post-metamorphic reactivation allowed magma ascent and pluton emplacement in the complex and adjacent supracrustal rocks within dilatational sites; and (iii) brittle-ductile shears that postdate high-grade metamorphism provided channel ways for fluid migration associated with magnetite-related mineralization. Although the complex does not host an economic mineral deposit, the role between structures at different levels and the combination of gravity and aeromagnetics at different scales provides an example of an approach for mineral exploration in similar high grade gneiss terrains.

  8. Mineral Fiber Toxicology

    The chemical and physical properties of different forms of mineral fibers impact biopersistence and pathology in the lung. Fiber chemistry, length, aspect ratio, surface area and dose are critical factors determining mineral fiber-associated health effects including cancer and as...

  9. Mineral commodity summaries 2017

    Ober, Joyce A.


    This report is the earliest Government publication to furnish estimates covering 2016 nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for more than 90 individual minerals and materials.

  10. Depósitos epitermales de baja sulfuración ricos en sulfuros de metales base, distrito aurífero La Carolina, San Luis, Argentina

    Gallard-Esquivel María Cecilia


    Full Text Available Low-sulfidation epithermal base-metal sulfide-rich deposits, La Carolina gold-bearing district,San Luis, Argentina. La Carolina gold-bearing district is located at the western end of the Metallogenetic Belt of San Luis, which is spatially and genetically related to the mesosilicic volcanism of mio-pliocene age. The volcanic arc experienced an eastward migration, due to the flattening of the Nazca plate in the segment 27°-33°S, known as the Pampean flat-slab. At La Carolina, the volcanic activity occurred between 8.2 and 6.3 Ma. It encompasses lavas and pyroclastics of andesitic, dacitic, latitic and trachytic composition. The mesosilicic magmas belong to normal to high-k calc-alkaline and shoshonitic suites. Structural analysis shows that previous structures have strongly controlled the emplacement of volcanic rocks and related mineral deposits at La Carolina allowing to define a pullapart.In this gold-bearing district there are eigth small mineralized prospects. The mineralogy consists of pyrite, arsenic rich pyrite, galena, sphalerite, marcasite, melnikovite, chalcopyrite, pyrrhotite, arsenopyrite, tennantitetetrahedrite, digenite, covellite, bornite, pyrargiryte, hessite, silvanite, pearceite, argirodite, gold, silver, greigite, boulangerite, jamesonite and electrum. The gangue consists of quartz, calcite, chalcedony and minor adularia.The hydrothermal alteration is widespread and comprise phyllic and argillic mineral assemblages characterized by sericite, illite, interstratified I/S, and silicic; propylitic alteration is also present as an outer halo. Fluid inclusions studies show that the formation temperatures range between 230º to 330º C. Boiling and mixing with meteoric water led to mineral precipitation. Based on the mineralogy, textures, hydrothermal alteration, formation temperatures,fluid chemistry and prospective geochemistry the mineralizations have been classified as low-sulfidation epithermal base-metal sulfide-rich deposits.

  11. Marine Mineral Exploration

    The past 20 years have seen extensive marine exploration work by the major industrialized countries. Studies have, in part, been concentrated on Pacific manganese nodule occurrences and on massive sulfides on mid-oceanic ridges. An international jurisdictional framework of the sea-bed mineral...... in EEZ areas are fairly unknown; many areas need detailed mapping and mineral exploration, and the majority of coastal or island states with large EEZ areas have little experience in exploration for marine hard minerals. This book describes the systematic steps in marine mineral exploration....... Such exploration requires knowledge of mineral deposits and models of their formation, of geophysical and geochemical exploration methods, and of data evaluation and interpretation methods. These topics are described in detail by an international group of authors. A short description is also given of marine...

  12. Mineral Commodity Summaries 2008



    Each chapter of the 2008 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest comprehensive source of 2007 mineral production data for the world. More than 90 individual minerals and materials are covered by two-page synopses. National reserves and reserve base information for most mineral commodities found in this report, including those for the United States, are derived from a variety of sources. The ideal source of such information would be comprehensive evaluations that apply the same criteria to deposits in different geographic areas and report the results by country. In the absence of such evaluations, national reserves and reserve base estimates compiled by countries for selected mineral commodities are a primary source of national reserves and reserve base information. Lacking national assessment information by governments, sources such as academic articles, company reports, common business practice, presentations by company representatives, and trade journal articles, or a combination of these, serve as the basis for national reserves and reserve base information reported in the mineral commodity sections of this publication. A national estimate may be assembled from the following: historically reported reserves and reserve base information carried for years without alteration because no new information is available; historically reported reserves and reserve base reduced by the amount of historical production; and company reported reserves. International minerals availability studies conducted by the U.S. Bureau of Mines, before 1996, and estimates of identified resources by an international collaborative effort (the International Strategic Minerals

  13. Why Mineral Interfaces Matter

    Putnis, Andrew; Putnis, Christine V.


    While it is obvious that reactions between a mineral and an aqueous solution take place at the mineral-fluid interface it is only relatively recently that high spatial resolution studies have demonstrated how the local structure of the mineral surface and the chemical composition of the fluid at the interface control both the short-range and the long-range consequences of mineral-fluid interaction. Long-range consequences of fluid-mineral interaction control element cycles in the earth, the formation of ore-deposits, the chemical composition of the oceans through weathering of rocks and hence climate changes. Although weathering is clearly related to mineral dissolution, to what extent do experimentally measured dissolution rates of minerals help to understand weathering, especially weathering mechanisms? This question is related to the short-range, local reactions that take place when a mineral, that is not stable in the fluid, begins to dissolve. In this case the fluid composition at the interface will become supersaturated with respect to a different phase or phases. This may be a different composition of the same mineral e.g. a Ca-rich feldspar dissolving in a Na-rich solution results in a fluid at the interface which may be supersaturated with respect to an Na-rich feldspar. Alternatively, the interfacial fluid could be supersaturated with respect to a different mineral e.g. an Na-rich zeolite, depending on the temperature. Numerous experiments have shown that the precipitation of a more stable phase at the mineral-fluid interface results in a coupling between the dissolution and the precipitation, and the replacement of one mineral by another. This process separates the short-range mechanisms which depend only on the composition of the interfacial solution, and the long-range consequences that depend on the composition of the residual fluid released from the reacting parent mineral. Typically such residual fluids may carry metal ions tens to hundreds of

  14. Mineral facilities of Europe

    Almanzar, Francisco; Baker, Michael S.; Elias, Nurudeen; Guzman, Eric


    This map displays over 1,700 records of mineral facilities within the countries of Europe and western Eurasia. Each record represents one commodity and one facility type at a single geographic location. Facility types include mines, oil and gas fields, and plants, such as refineries, smelters, and mills. Common commodities of interest include aluminum, cement, coal, copper, gold, iron and steel, lead, nickel, petroleum, salt, silver, and zinc. Records include attributes, such as commodity, country, location, company name, facility type and capacity (if applicable), and latitude and longitude geographical coordinates (in both degrees-minutes-seconds and decimal degrees). The data shown on this map and in table 1 were compiled from multiple sources, including (1) the most recently available data from the U.S. Geological Survey (USGS) Minerals Yearbook (Europe and Central Eurasia volume), (2) mineral statistics and information from the USGS Minerals Information Web site (, and (3) data collected by the USGS minerals information country specialists from sources, such as statistical publications of individual countries, annual reports and press releases of operating companies, and trade journals. Data reflect the most recently published table of industry structure for each country at the time of this publication. Additional information is available from the country specialists listed in table 2.

  15. Design of a rotating facility for extracorporal treatment of an explanted liver with disseminated metastases by boron neutron capture therapy with an epithermal neutron beam.

    Nievaart, V A; Moss, R L; Kloosterman, J L; van der Hagen, T H J J; van Dam, H; Wittig, A; Malago, M; Sauerwein, W


    In 2001, at the TRIGA reactor of the University of Pavia (Italy), a patient suffering from diffuse liver metastases from an adenocarcinoma of the sigmoid was successfully treated by boron neutron capture therapy (BNCT). The procedure involved boron infusion prior to hepatectomy, irradiation of the explanted liver at the thermal column of the reactor, and subsequent reimplantation. A complete response was observed. This encouraging outcome stimulated the Essen/Petten BNCT group to investigate whether such an extracorporal irradiation could be performed at the BNCT irradiation facility at the HFR Petten (The Netherlands), which has very different irradiation characteristics than the Pavia facility. A computational study has been carried out. A rotating PMMA container with a liver, surrounded by PMMA and graphite, is simulated using the Monte Carlo code MCNP. Due to the rotation and neutron moderation of the PMMA container, the initial epithermal neutron beam provides a nearly homogeneous thermal neutron field in the liver. The main conditions for treatment as reported from the Pavia experiment, i.e. a thermal neutron fluence of 4 x 10(12) +/- 20% cm(-2), can be closely met at the HFR in an acceptable time, which, depending on the defined conditions, is between 140 and 180 min.

  16. Analysis of air particulate matter in Teflon trademark and quartz filters by short-irradiation, epithermal-neutron activation with Compton suppression

    Freitas, M.C.; Almeida, S.M.; Dung, H.M.; Dionisio, I. [URSN, Sacavem (Portugal). Instituto Tecnologico e Nuclear (ITN); Pacheco, A.M.G. [Technical Univ. of Lisboa (Portugal). CERENA-IST


    This work aimed at developing methodologies to characterize the elemental composition of air particulate matter (APM) collected in Portugal, at an urban area (Lisboa, mainland Portugal) and at a remote location (Terceira island, Azores, Portugal). The Azores' collections were based on quartz filters; Teflon trademark filters were used at the urban area. The main components of Teflon trademark and quartz filters are fluorine and silica, respectively, the latter featuring higher levels of elements in the blanks. Al and Ti are reduced to null values when the blanks are subtracted. Epithermal short irradiation associated to Compton suppression in the measurement allowed the determination of a set of elements potentially representative of important emission sources: seaspray (Cl, Br, Na, Mg), fuel burning (V), incineration (Cl), soil resuspension (Mg, Mn, Na, U, V), and traffic (Br, Mn). The analysis was fast due to the use of an automatic system. In some cases, the same element had different origins in the urban and remote oceanic areas. (orig.)

  17. Mineral resources of Antarctica

    Compiled and edited by Wright, Nancy A.; Williams, Paul L.


    Although the existence of mineral deposits in Antarctica is highly probable, the chances of finding them are quite small. Minerals have been found there in great variety but only as occurrences. Manganese nodules, water (as ice), geothermal energy, coal, petroleum, and natural gas are potential resources that could perhaps be exploited in the future. On the basis of known mineral occurrences in Antarctica and relationships between geologic provinces of Antarctica and those of neighboring Gondwana continents, the best discovery probability for a base-metal deposit in any part of Antarctica is in the Andean orogen; it is estimated to be 0.075 (75 chances in 1,000).

  18. Remote Sensing Analysis of Mineralized Alteration in the Ramand Area (Qazvin Province

    Seyed Abolfazl Ezzati


    Full Text Available Introduction The Ramand area, southwest of Buin- Zahra, about 60 kilometers from Qazvin, lies in the igneous belt of the Urmieh-Dokhtar region, the main structural zone of north-central Iran. Rhyodacite and rhyolite lava flows are the principal host rocks of mineralization and alteration of the area, most of which occurs in faulted and brecciated zones alongmaj or northwest-trending fault systems (such as Kour-Cheshmeh, Hassan Abad and their branches. Clay minerals determined from satellite images indicated principally argillic hydrothermal alteration before laboratory mineralogical analysis. According to instrumental analyses, mineralized alteration with greater amounts of argillic halos and lesser amounts of sericitic-propylitic minerals contains quartz veinlets in the vertical and lateral sections. Initially, alteration in the Ramand area was revealed in ETM images by using the SPCA technique of Crosta and Moore, 1990 (Selective Principle Component Analysis. Compared with other techniques, SPCA results have reliable spectral signatures for identifying argillic minerals and Fe-oxides as the main mineralogical association in hydrothermal environments. Subsequently, multispectral images (ASTER were analyzed using band ratios.The results indicated silicification alteration along the faulted regions in the Ramand area. Later, areas of silicification alteration were prospected for precious and base metal mineralization.Sampling results suggested that the altered areas have some potential for epithermal mineralization, according to instrumental analyses and micrographic evidence. Materials and methods 1- Collecting satellite images, geological evidence and related documents 2- Image processing to reveal and identify the mineralized alteration. 3- Sampling of the mineralized zones indicated by the remote sensing. 4- Thin- and polished section microscopic studies. 5- X-ray diffraction analysis (XRD (19 samples, inductively coupled plasma mass

  19. [Synthetic mineral fibers].

    Boillat, M A


    The group of man-made mineral fibres includes slagwool, glasswool, rockwool, glass filaments and microfibres, as well as refractory ceramic fibres. The toxicity of mineral fibres is determined by several factors such as the diameter (ceramic fibres. A slightly elevated standard mortality ratio for lung cancer has been documented in large cohorts of workers (USA, Europe and Canada) exposed to man-made mineral fibres, especially in the early technological phase. It is not possible to determine from these data whether the risk of lung cancer is due to the man-made mineral fibres themselves, in particular due to the lack of data on smoking habits. No increased risk of mesothelioma has been demonstrated in these cohorts. Epidemiological data are insufficient at this time concerning neoplastic diseases in refractory ceramic fibres.

  20. Minerals in environmental technology

    Schuiling, R.D. [Utrecht Univ., Utrecht (Netherlands). Faculty of Earth Sciences


    Minerals play a key role in the environment; this role is often not well understood, because the emphasis of most environmentalists is on air, water, or the composition of solid wastes as a whole, without paying attention to their mineralogical composition. Several minerals can serve as effective and cheap adsorbents for many toxic chemicals. Several minerals can be used as a cheap substitute for expensive chemicals in environmental technologies. Environmental technologies that produce an economically interesting mineral will have an edge over competing technologies. Most of the problems, overreaction, panicky and expensive measures with regard to exposure from quartz and asbestos stem from a poor understanding of natural levels of common contaminants, a disregard for mineralogy, and a lack of insight into natural processes in general.

  1. sequenceMiner algorithm

    National Aeronautics and Space Administration — Detecting and describing anomalies in large repositories of discrete symbol sequences. sequenceMiner has been open-sourced! Download the file below to try it out....

  2. Vitamins and Minerals

    ... minerals your body needs. But if you're skipping meals, dieting, or if you're concerned that ... Kids For Parents MORE ON THIS TOPIC Healthy Breakfast Planner Nutrition & Fitness Center Vitamin D Figuring Out ...

  3. Multiple Mesozoic mineralization events in South China—an introduction to the thematic issue

    Hu, Rui-Zhong; Zhou, Mei-Fu


    Mesozoic mineral deposits in South China include world-class deposits of W, Sn and Sb and those that provide the major sources of Ta, Cu, Hg, As, Tl, Pb, Zn, Au and Ag for the entire country. These deposits can be classified into polymetallic hydrothermal systems closely related to felsic intrusive rocks (Sn-W -Mo granites, Cu porphyries, polymetallic and Fe skarns, and polymetallic vein deposits) and low-temperature hydrothermal systems with no direct connection to igneous activities (MVT deposits, epithermal Au and Sb deposits). Recent studies have shown that they formed in the Triassic (Indosinian), Jurassic-Cretaceous (Early Yanshanian), and Cretaceous (Late Yanshanian) stages. Indosinian deposits include major MVT (Pb-Zn-Ag) deposits and granite-related W-Sn deposits. Early Yanshanian deposits are low-temperature Sb-Au and high-temperature W-Sn and Cu porphyry types. Many Late Yanshanian deposits are low-temperature Au-As-Sb-Hg and U deposits, and also include high-temperature W-Sn polymetallic deposits. The formation of these deposits is linked with a specific tectonothermal evolution and igneous activities. This special issue brings together some of the latest information in eight papers that deal with the origins and tectonic environments of mineral deposits formed in these stages. We anticipate that this issue will stimulate more interests in these ore deposits in South China.

  4. Mathematical model for bone mineralization

    Svetlana V Komarova


    Full Text Available Defective bone mineralization has serious clinical manifestations, including deformities and fractures, but the regulation of this extracellular process is not fully understood. We have developed a mathematical model consisting of ordinary differential equations that describe collagen maturation, production and degradation of inhibitors, and mineral nucleation and growth. We examined the roles of individual processes in generating normal and abnormal mineralization patterns characterized using two outcome measures: mineralization lag time and degree of mineralization. Model parameters describing the formation of hydroxyapatite mineral on the nucleating centers most potently affected the degree of mineralization, while the parameters describing inhibitor homeostasis most effectively changed the mineralization lag time. Of interest, a parameter describing the rate of matrix maturation emerged as being capable of counter-intuitively increasing both the mineralization lag time and the degree of mineralization. We validated the accuracy of model predictions using known diseases of bone mineralization such as osteogenesis imperfecta and X-linked hypophosphatemia. The model successfully describes the highly non-linear mineralization dynamics, which includes an initial lag phase when osteoid is present but no mineralization is evident, then fast primary mineralization, followed by secondary mineralization characterized by a continuous slow increase in bone mineral content. The developed model can potentially predict the function for a mutated protein based on the histology of pathologic bone samples from mineralization disorders of unknown etiology.

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

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


    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

  6. The mineral economy of Brazil--Economia mineral do Brasil

    Gurmendi, Alfredo C.; Barboza, Frederico Lopes; Thorman, Charles H.


    This study depicts the Brazilian government structure, mineral legislation and investment policy, taxation, foreign investment policies, environmental laws and regulations, and conditions in which the mineral industry operates. The report underlines Brazil's large and diversified mineral endowment. A total of 37 mineral commodities, or groups of closely related commodities, is discussed. An overview of the geologic setting of the major mineral deposits is presented. This report is presented in English and Portuguese in pdf format.

  7. Measuring the Hardness of Minerals

    Bushby, Jessica


    The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

  8. Extraterrestrial magnetic minerals

    Pechersky, D. M.; Markov, G. P.; Tsel'movich, V. A.; Sharonova, Z. V.


    Thermomagnetic and microprobe analyses are carried out and a set of magnetic characteristics are measured for 25 meteorites and 3 tektites from the collections of the Vernadsky Geological Museum of the Russian Academy of Sciences and Museum of Natural History of the North-East Interdisciplinary Science Research Institute, Far Eastern Branch of the Russian Academy of Sciences. It is found that, notwithstanding their type, all the meteorites contain the same magnetic minerals and only differ by concentrations of these minerals. Kamacite with less than 10% nickel is the main magnetic mineral in the studied samples. Pure iron, taenite, and schreibersite are less frequent; nickel, various iron spinels, Fe-Al alloys, etc., are very rare. These minerals are normally absent in the crusts of the Earth and other planets. The studied meteorites are more likely parts of the cores and lower mantles of the meteoritic parent bodies (the planets). Uniformity in the magnetic properties of the meteorites and the types of their thermomagnetic (MT) curves is violated by secondary alterations of the meteorites in the terrestrial environment. The sediments demonstrate the same monotony as the meteorites: kamacite is likely the only extraterrestrial magnetic mineral, which is abundant in sediments and associated with cosmic dust. The compositional similarity of kamacite in iron meteorites and in cosmic dust is due to their common source; the degree of fragmentation of the material of the parent body is the only difference.

  9. Evolution of the Creede Caldera and its relation to mineralization in the Creede mining district, Colorado

    Barton, Paul B.; Rye, Robert O.; Bethke, Philip M.


    At 25 Ma a major epithermal silver and base metal deposit formed in rhyolitic welded tuff near Creede, Colorado. Nearly 24000 metric tons of silver, appreciable lead, and small amounts of zinc, copper, and gold, have been produced from large, crustified veins under Bachelor and Bulldog Mountains north and northwest of Creede. Prior geologic, hydrologic, and stable-isotope studies showed that ore deposition was associated with the mixing and boiling of waters from diverse sources and suggester that a critical part of the ore-forming fluid may have originated within the ancient lake and sediments of the lacustrine Creede Formation that filled the Creede caldera. Two drill holes that sampled the heretofore hidden lower half of the Creede Formation are the focus of this book. The Creede caldera formed at 26.9 Ma within a high constructional plateau of silicic ashflows that covered and were sporadically interlayed with, intermediate lavas and lahars from large stratovolcanoes. The Creede caldera lake had an inflow evaporation balance that did not permit rapid filling to create a brim-full deep lake. Thus salts were evaporatively concentrated; but, with the exception of possible gypsum, no evaporite minerals preserved. Cool springs deposited travertine as mounds and contributed to limestone interlaminations within the sediment. The lake bottom was anoxic, and bacterial reduction of sulfate led to extreme sulfur isotopic fractionation in diagenetic pyrite. The caldera gradually resurged, converting the initial equant lake into an arcuate moat. Resurgent doming, alluvial fans, lacustrine sediments, ashfalls, and lava domes displaced water, lifted the lake so that it overlapped what later became the southern edge of the mineralized are, and eventually filled the basin. At 25.1 Ma an unseen pluton intruded beneath the northen part of the Creede district and created a convecting olume that drew in brine from the Creede caldera fill, meteotic water from highlands to the north

  10. Thorium in mineral products.

    Collier, D E; Brown, S A; Blagojevic, N; Soldenhoff, K H; Ring, R J


    Many ores contain low levels of thorium. When these ores are processed, the associated radioactivity can be found in mineral concentrates, intermediates and final products. There is an incentive for industries to remove radioactivity from mineral products to allow the movement and sale of these materials, both nationally and internationally, without the need for licensing. Control of thorium in various products involves the development and optimisation of process steps to be able to meet product specifications. The Australian Nuclear Science and Technology Organisation (ANSTO) has undertaken a range of R & D programmes targeting the treatment of thorium-bearing minerals. This paper discusses the application of a microprobe technique for siting radioactivity in zircon and ilmenite and the problems experienced in measuring the concentrations in solid rare earth products.

  11. Microbially mediated mineral carbonation

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.


    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  12. Optimization design for the epithermal neutron duct of in-hospital neutron irradiator mark 1 reactor%医院中子照射器Ⅰ型堆超热中子束流孔道的优化设计

    江新标; 朱养妮; 赵柱民; 陈立新; 周永茂


    采用蒙特卡罗程序(Monte Carlo neutron and photo transport code,MCNP)对医院中子照射器Ⅰ型堆(IHNI-1)超热中子束流孔道的慢化层、反射层进行了优化设计.首先对FLUENTAL、Al等材料组成的6种慢化体方案进行了分析比较,给出了孔道出口处超热中子通量密度较大的两种设计方案;基于此两种慢化体设计方案,在保持束流孔道外框尺寸不变情况下,对慢化体周围的反射层进行了分析比较,给出了反射层的推荐方案;基于慢化体和反射层优化方案,最后给出了超热中子束流孔道出口处束流参数的空间分布.%Optimization design for the moderation layer and reflection layer of the epithermal neutron duct at in-hospital neutron irradiator mark 1(IHNI-1) reactor is carried out by using MCNP in this paper. Firstly, six moderator schemes combined with FLUENTAL are compared with Al materials, and two moderation optimization schemes which can obtain intensive epithermal neutron flux density at exit of this duct are chosen. Secondly, based on these two moderation schemes, the optimization design for reflectors around the moderator is introduced, and the recommended reflector schemes are given. Finally, based on the moderation layer and reflection layer optimization schemes, the neutron and gamma space distribution of the epithermal neutron beam at exit of this duct are detailed calculated.

  13. Mineralization of fossil wood

    Buurman, P.


    Several pieces of fossil wood have been analyzed with X-ray diffraction and were grouped on the basis of mineralogical composition. Various mineralizations were studied in thin sections and by means of the scanning electron microscope. Wood-opals appear to show a structure preservation that points t

  14. Clay Mineral: Radiological Characterization

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.


    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  15. Mixtures and mineral reactions

    Saxena, S.; Ganguly, J.


    Considerable progress has been made in our understanding of the physicochemical evolution of natural rocks through systematic analysis of the compositional properties and phase relations of their mineral assemblages. This book brings together concepts of classical thermodynamics, solution models, and atomic ordering and interactions that constitute a basis of such analysis, with examples of application to subsolidus petrological problems.

  16. Bioleaching of Minerals

    F. Roberto


    Bioleaching is the term used to describe the microbial dissolution of metals from minerals. The commercial bioleaching of metals, particularly those hosted in sulfide minerals, is supported by the technical disciplines of biohydrometallurgy, hydrometallurgy, pyrometallurgy, chemistry, electrochemistry, and chemical engineering. The study of the natural weathering of these same minerals, above and below ground, is also linked to the fields of geomicrobiology and biogeochemistry. Studies of abandoned and disused mines indicate that the alterations of the natural environment due to man's activities leave as remnants microbiological activity that continues the biologically mediated release of metals from the host rock (acid rock drainage; ARD). A significant fraction of the world's copper, gold and uranium is now recovered by exploiting native or introduced microbial communities. While some members of these unique communities have been extensively studied for the past 50 years, our knowledge of the composition of these communities, and the function of the individual species present remains relatively limited. Nevertheless, bioleaching represents a major strategy in mineral resource recovery whose importance will increase as ore reserves decline in quality, become more difficult to process (due to increased depth, increased need for comminution, for example), and as environmental considerations eliminate traditional physical processes such as smelting, which have served the mining industry for hundreds of years.

  17. Aggregate and Mineral Resources - Industrial Mineral Mining Operations

    NSGIC Education | GIS Inventory — An Industrial Mineral Mining Operation is a DEP primary facility type related to the Industrial Mineral Mining Program. The sub-facility types are listed below:Deep...

  18. Aggregate and Mineral Resources - Industrial Mineral Mining Operations

    NSGIC GIS Inventory (aka Ramona) — An Industrial Mineral Mining Operation is a DEP primary facility type related to the Industrial Mineral Mining Program. The sub-facility types are listed below:Deep...

  19. Carbon Mineral Ecology: Predicting the Undiscovered Minerals of Carbon

    Hazen, R. M.; Hummer, D. R.; Downs, R. T.; Hystad, G.; Golden, J.


    The diversity and distribution of Earth's minerals through deep time reflects key events in our planet's crustal evolution. Studies in mineral ecology exploit mineralogical databases to document diversity-distribution relationships of minerals, which reveal that all carbon-bearing minerals, as well as subsets containing C with O, H, Ca, or Na, conform to Large Number of Rare Events (LNRE) distributions. LNRE models facilitate prediction of total mineral diversity, and thus point to minerals that exist on Earth but have not yet been discovered and described. Our model predicts that at least 548 C minerals exist on Earth today, indicating that at least 145 carbon-bearing mineral species have yet to be discovered. Furthermore, by analyzing subsets of the most common additional elements in carbon-bearing minerals (i.e., 378 C + O species; 282 C + H species; 133 C + Ca species; and 100 C + Na species), we predict that 129 of these missing carbon minerals contain oxygen, 118 contain hydrogen, 52 contain calcium, and more than 60 contain sodium. The majority of these as yet undescribed minerals are predicted to be hydrous carbonates, many of which may have been overlooked because they are colorless, poorly crystalized, and/or water-soluble. We propose the identities of plausible as yet undescribed carbon minerals, as well as search strategies for their discovery. Some of these minerals will be natural examples of known synthetic compounds, including carbides such as calcium carbide (CaC2), crystalline hydrocarbons such as pyrene (C16H10), and numerous oxalates, anhydrous carbonates, and hydrous carbonates. Many other missing carbon minerals will be isomorphs of known carbon minerals, notably of the more than 100 different hydrous carbonate structures. An understanding of Earth's "missing" minerals provides a more complete picture of geochemical processes that influence crustal evolution.

  20. Stable Te isotope fractionation in tellurium-bearing minerals from precious metal hydrothermal ore deposits

    Fornadel, Andrew P.; Spry, Paul G.; Haghnegahdar, Mojhgan A.; Schauble, Edwin A.; Jackson, Simon E.; Mills, Stuart J.


    The tellurium isotope compositions of naturally-occurring tellurides, native tellurium, and tellurites were measured by multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) and compared to theoretical values for equilibrium mass-dependent isotopic fractionation of representative Te-bearing species estimated with first-principles thermodynamic calculations. Calculated fractionation models suggest that 130/125Te fractionations as large as 4‰ occur at 100 °C between coexisting tellurates (Te VI) and tellurides (Te -II) or or native tellurium Te(0), and smaller, typically secondary emmonsite, δ130/125Te compositions were identical. The coincidence of δ130/125Te between all oxidized and reduced species in this study and the apparent lack of isotopic fractionation between native tellurium and emmonsite in one sample suggest that oxidation processes cause little to no fractionation. Because Te is predominantly transported as an oxidized aqueous phase or as a reduced vapor phase under hydrothermal conditions, either a reduction of oxidized Te in hydrothermal liquids or deposition of Te from a reduced vapor to a solid is necessary to form the common tellurides and native tellurium in ore-forming systems. Our data suggest that these sorts of reactions during mineralization may account for a ∼3‰ range of δ130/125Te values. Based on the data ranges for Te minerals from various ore deposits, the underpinning geologic processes responsible for mineralization seem to have primary control on the magnitude of fractionation, with tellurides in epithermal gold deposits showing a narrower range of isotope values than those in orogenic gold and volcanogenic massive sulfide deposits.

  1. Mineral processing of heavy mineral sands from Malawi and Malaysia

    Mitchell, C J


    Processing of heavy mineral sands involves many techniques including gravity, magnetic and electrostatic separation. As part of a laboratory programme to develop effective mineral processing techniques, two mineral sands from Malawi and Malaysia were processed using the standard techniques, with emphasis placed on the Carpco electrostatic separator. These sands were initially characterised mineralogically by scanning electron microscopy (SEM), electron microprobe analysis (EPMA...

  2. Adsorption of RNA on mineral surfaces and mineral precipitates

    Biondi, Elisa; Furukawa, Yoshihiro; Kawai, Jun


    The prebiotic significance of laboratory experiments that study the interactions between oligomeric RNA and mineral species is difficult to know. Natural exemplars of specific minerals can differ widely depending on their provenance. While laboratory-generated samples of synthetic minerals can have controlled compositions, they are often viewed as "unnatural". Here, we show how trends in the interaction of RNA with natural mineral specimens, synthetic mineral specimens, and co-precipitated pairs of synthetic minerals, can make a persuasive case that the observed interactions reflect the composition of the minerals themselves, rather than their being simply examples of large molecules associating nonspecifically with large surfaces. Using this approach, we have discovered Periodic Table trends in the binding of oligomeric RNA to alkaline earth carbonate minerals and alkaline earth sulfate minerals, where those trends are the same when measured in natural and synthetic minerals. They are also validated by comparison of co-precipitated synthetic minerals. We also show differential binding of RNA to polymorphic forms of calcium carbonate, and the stabilization of bound RNA on aragonite. These have relevance to the prebiotic stabilization of RNA, where such carbonate minerals are expected to have been abundant, as they appear to be today on Mars.

  3. Oxygen Extraction from Minerals

    Muscatello, Tony


    Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

  4. Marine minerals: The Indian perspective

    Gujar, A.R.; Nath, B.N.; Banerjee, R.

    The sea floor of the continental margins of India is covered by a wide variety of terrigenous, biogenous, and chemogenous mineral deposits. Terrigenous heavy mineral placers containing ilmenite, magnetite, monazite, zircon, and rutile are reported...

  5. Unmixing of spectrally similar minerals

    Debba, Pravesh


    Full Text Available -bearing oxide/hydroxide/sulfate minerals in complex mixtures be obtained using hyperspectral data? Debba (CSIR) Unmixing of spectrally similar minerals MERAKA 2009 3 / 18 Method of spectral unmixing Old method: problem Linear Spectral Mixture Analysis (LSMA...

  6. Agricultural Minerals Operations - Direct Download

    U.S. Geological Survey, Department of the Interior — This map layer includes agricultural minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  7. Construction Minerals Operations - Direct Download

    U.S. Geological Survey, Department of the Interior — This map layer includes construction minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

  8. Discussion on Nontraditional Mineral Resources


    In this paper, the authors introduce the concept of nontraditional mineral resources, and pro pose the major system of nontraditional mineral resources, including nontraditional resources, research methods, mining and mineral economics. Then the authors conclude that the research on nontraditional mineral resources is not only significant to satisfication the human needs in the 21st century, but also important to the development of the present geological theory.

  9. Aggregates from mineral wastes

    Baic Ireneusz


    Full Text Available The problem concerning the growing demand for natural aggregates and the need to limit costs, including transportation from remote deposits, cause the increase in growth of interest in aggregates from mineral wastes as well as in technologies of their production and recovery. The paper presents the issue related to the group of aggregates other than natural. A common name is proposed for such material: “alternative aggregates”. The name seems to be fully justified due to adequacy of this term because of this raw materials origin and role, in comparison to the meaning of natural aggregates based on gravel and sand as well as crushed stones. The paper presents characteristics of the market and basic application of aggregates produced from mineral wastes, generated in the mining, power and metallurgical industries as well as material from demolished objects.

  10. Rock and mineral magnetism

    O’Reilly, W


    The past two decades have witnessed a revolution in the earth sciences. The quantitative, instrument-based measurements and physical models of. geophysics, together with advances in technology, have radically transformed the way in which the Earth, and especially its crust, is described. The study of the magnetism of the rocks of the Earth's crust has played a major part in this transformation. Rocks, or more specifically their constituent magnetic minerals, can be regarded as a measuring instrument provided by nature, which can be employed in the service of the earth sciences. Thus magnetic minerals are a recording magnetometer; a goniometer or protractor, recording the directions of flows, fields and forces; a clock; a recording thermometer; a position recorder; astrain gauge; an instrument for geo­ logical surveying; a tracer in climatology and hydrology; a tool in petrology. No instrument is linear, or free from noise and systematic errors, and the performance of nature's instrument must be assessed and ...

  11. Iodine mineral waters

    Iluta Alexandru


    Full Text Available Iodine mineral waters are found especially in sub-Carpathian region, also in regions with Salif deposits. Waters are currently used iodine in drinking cure for chaps and Basedow. Are also indicated in balneology. Iodine water containing at least 1 mg L, there is pure iodine is usually given the nature of other types of mineral waters further: sodium chlorinated water (Bazna (50-70 mg iodine / l, Baile Govora (50 - 70 mg / l, Bălţăteşti (4-5 mg / l, salted Monteoru (30 mg / l, mine water mixed alkaline chlorination, sulphate, which are indicated for crenoterapie (hypo or isotonic to the bathrooms Olăneşti or Călimăneşti-Căciulata.

  12. Coastal placer minerals

    Iyer, S.D.; Gujar, A.R.

    by mechanical concentration and natural gravity separation of mineral particles derived from weathered rocks. The formation of placers requires factors such as: climate, source rock, weathering, transport, deposition, concentration, high specific gravity... and transport of the rocks. For example, in cold and glaciated regions, there would be limited physical weathering and less concentration and more dispersion of the weathered material and placers would not FE AT U R E FE AT U R E A RT IC LE form...

  13. Mineral metabolism in cats

    Pineda Martos, Carmen María


    The present Doctoral Thesis wa metabolism in the feline species. Through a series of studies, the relationship between calcium metabolism and the main hormones involved in it has been determined metabolism during the juvenile stage of growing cats effects linked to feeding calculolytic diets on feline mineral metabolism. The first part of the work was aimed the quantification of intact (I-PTH) and whole PTH) and to characterize the dynamics of PTH secretion, including ...

  14. Culture systems: mineral oil overlay.

    Morbeck, Dean E; Leonard, Phoebe H


    Mineral oil overlay microdrop is commonly used during in vitro fertilization (IVF) procedures. Though mineral oil appears homogeneous, it is an undefined product that can vary in quality. Here, we describe the history, chemistry, processing, and optimal use of mineral oil for IVF and embryo culture.

  15. Polymer-mediated mesoscale mineralization

    CHEN ShaoFeng; YU ShuHong


    Polymer-controlled mineralization in aqueous solution or in a mixed solvent media, as well as its com-bination with the interface of air-water can lead to the formation of minerals with unique structures and morphologies, which sheds light on the possibility to mimic the detailed structures of the natural min-erals.

  16. Definitions of Health Terms: Minerals

    ... this page: Definitions of Health Terms : Minerals To use the sharing features on ... of the minerals that you need. Find more definitions on Fitness | General Health | Minerals | Nutrition | Vitamins Antioxidants Antioxidants are substances that ...

  17. Refractory Minerals in Henan Province

    JIN Qinguo; LI Jing; LIU Jiehua; LIU Yanjun


    Henan province is very rich in refractory minerals of many varieties including silica, dolomite, graphite,pearlite, sepiolite, olivine, and sillimanite group minerals, besides the abundant reserves of fireclay and bauxite,which lay a good foundation for the development of the refractories industry of the province. The paper introduces the reserves, distribution and character of the refractory minerals in Henan province.

  18. Fluid inclusion and stable isotope study of telluride mineralization at Mahd Adh Dhahab, Saudi Arabia

    Afifi, A.M.; Kelly, W.C.


    Mahd Adh Dhahab is unique among Precambrian gold deposits in that it displays many characteristics of epithermal precious metal districts. Au-Ag-Cu-Zn-Pb mineralization occurs principally in the third of five generations of quartz veins. Sulfur isotopic equilibrium was generally maintained among sulfides which range in delta/sup 34/S from -1.8 (galena) to 6.4 (pyrite). The narrow range in delta/sup 34/S of sulfides is inconsistent with large variations in f02 calculated from chlorite +/- pyrite +/- hematite assemblages. Galena-sphalerite pairs yield temperatures in the range 160-270/sup 0/C for stage 3 veins, which fall within the 120-300/sup 0/C range defined by fluid inclusion thermometry. Fluid salinities are in the range 0.5 wt.% NaCl equivalent. The trends indicate mixing of delta/sup 18/O approx. = 0 waters with heavier more oxidized waters during stage 4 deposition which led to non-equilibrium oxidation of H/sub 2/S. deltaD values of vein chlorites fall within a narrow range of -65 to -75, while deltaD measurements of inclusion fluids in quartz display a wider spread from -13 to -43; the lighter values may reflect contamination by secondary inclusions. The stable isotope data indicate probable derivation of both sulfur and carbon from igneous sources. District-wide variation in sulfur and oxygen isotopes indicate the presence of several hydrothermal centers, which has possible significance to exploration.


    Rchard D. Miles


    Full Text Available Para determinar a eficiência de utilização de elementos minerais dietéticos, deve-se conhecer a biodisponibilidade relativa de cada elemento de um determinado ingrediente ou de uma ração completa. Análises químicas da dieta ou de um determinado ingrediente não indicam a efetividade biológica de um nutriente. Existem muitos fatores que influenciam a biodisponibilidade dos minerais, especialmente dos minerais-traço, tais como: nível de consumo do mineral, forma química, digestibilidade da dieta, tamanho da partícula, interações com outros minerais e nutrientes, agentes quelantes, inibidores, estado fisiológico do animal, qualidade da água, condições de processamento ao qual ingredientes individuais ou uma dieta completa foram expostos e, é óbvio, a idade e a espécie animal. Quando um mineral-traço é ingerido, sua biodisponibilidade é influenciada por propriedades específicas do mineral da maneira como está incluído na dieta. Por exemplo, sua valência e forma molecular (orgânica versus inorgânica são importantes. Por causa dessas propriedades específicas, o mineral pode formar complexos com outros componentes no intestino, o que pode dificultar ou facilitar a absorção pela mucosa, o transporte ou o metabolismo do mineral no organismo. É bem conhecido que certos minerais em sua forma inorgânica competem com outros minerais por sítios de ligação e por absorção no intestino. O conhecimento sobre a biodisponibilidade dos minerais-traço nos ingredientes e fontes suplementares é importante para a formulação econômica de uma ração para garantir ótimo desempenho animal. A biodisponibilidade deve ser entendida como um valor “estimado” que reflete a absorção e a utilização do mineral sobre condições de um experimento específico e não de uma propriedade inerente e específica de um ingrediente ou suplemento de ração. Com a tecnologia disponível, a determinação da biodisponibilidade dentro de

  20. Characterization of refractory behaviour of complex gold/silver ore by diagnostic leaching



    The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. <38 μm) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.

  1. Synthesis of bimetallic gold-silver alloy nanoclusters by simple mortar grinding.

    Murugadoss, Arumugam; Kai, Noriko; Sakurai, Hidehiro


    A macroscale quantity of bimetallic Au-Ag alloy nanoclusters was achieved through sequential reduction by simple mortar grinding. The chitosan biopolymer was used as both a stabilizing and reducing agent. These nanoclusters exhibit excellent catalytic activity toward the reduction of 4-nitrophenol.

  2. Enhanced antibacterial activity of bimetallic gold-silver core-shell nanoparticles at low silver concentration

    Banerjee, Madhuchanda; Sharma, Shilpa; Chattopadhyay, Arun; Ghosh, Siddhartha Sankar


    Herein we report the development of bimetallic Au@Ag core-shell nanoparticles (NPs) where gold nanoparticles (Au NPs) served as the seeds for continuous deposition of silver atoms on its surface. The core-shell structure and morphology were examined by UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). The core-shell NPs showed antibacterial activity against both Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive (Enterococcus faecalis and Pediococcus acidilactici) bacteria at low concentration of silver present in the shell, with more efficacy against Gram negative bacteria. TEM and flow cytometric studies showed that the core-shell NPs attached to the bacterial surface and caused membrane damage leading to cell death. The enhanced antibacterial properties of Au@Ag core-shell NPs was possibly due to the more active silver atoms in the shell surrounding gold core due to high surface free energy of the surface Ag atoms owing to shell thinness in the bimetallic NP structure.Herein we report the development of bimetallic Au@Ag core-shell nanoparticles (NPs) where gold nanoparticles (Au NPs) served as the seeds for continuous deposition of silver atoms on its surface. The core-shell structure and morphology were examined by UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). The core-shell NPs showed antibacterial activity against both Gram negative (Escherichia coli and Pseudomonas aeruginosa) and Gram positive (Enterococcus faecalis and Pediococcus acidilactici) bacteria at low concentration of silver present in the shell, with more efficacy against Gram negative bacteria. TEM and flow cytometric studies showed that the core-shell NPs attached to the bacterial surface and caused membrane damage leading to cell death. The enhanced antibacterial properties of Au@Ag core-shell NPs was possibly due to the more active silver atoms in the shell surrounding gold core due to high surface free energy of the surface Ag atoms owing to shell thinness in the bimetallic NP structure. Electronic supplementary information (ESI) available. See DOI: 10.1039/c1nr10703h

  3. Protein retention on plasma-treated hierarchical nanoscale gold-silver platform

    Fang, Jinghua; Levchenko, Igor; Mai-Prochnow, Anne; Keidar, Michael; Cvelbar, Uros; Filipic, Gregor; Han, Zhao Jun; Ostrikov, Kostya (Ken)


    Dense arrays of gold-supported silver nanowires of about 100 nm in diameter grown directly in the channels of nanoporous aluminium oxide membrane were fabricated and tested as a novel platform for the immobilization and retention of BSA proteins in the microbial-protective environments. Additional treatment of the silver nanowires using low-temperature plasmas in the inductively-coupled plasma reactor and an atmospheric-pressure plasma jet have demonstrated that the morphology of the nanowire array can be controlled and the amount of the retained protein may be increased due to the plasma effect. A combination of the neutral gold sublayer with the antimicrobial properties of silver nanowires could significantly enhance the efficiency of the platforms used in various biotechnological processes.

  4. Multipactor suppression by micro-structured gold/silver coatings for space applications

    Nistor, Valentin, E-mail: [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); González, Luis A. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Aguilera, Lydya; Montero, Isabel [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Galán, Luis [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Wochner, Ulrich [Tesat Spacecom GmbH and Co. KG,Gerberstr. 49, D-71522 Backnang (Germany); Raboso, David [European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), 2200 AG Noordwijk (Netherlands)


    Highlights: • Total suppression of the multipactor effect was achieved for a specific configuration of a high RF power K{sub u}-band waveguide. • Secondary emission of electrons was decreased by surfaces of high aspect ratio. • Simple techniques were used in the manufacturing of metallic microscopical rough coatings. • Surface analysis of the treatment was performed. • The RF insertion losses were improved with respect to Alodine, the standard coating for space applications. - Abstract: The secondary electron emission (SEE) from materials used in high power RF devices in space is the main trigger and sustaining mechanism of the resonant avalanche electron discharge known as the multipactor effect. It limits the attainable power of those devices. During recent decades, some scientific research has been focused on material properties for obtaining anti-multipactor coatings of low secondary emission yield (SEY). The European Space Agency (ESA) is leading a technological research on a new approach based on surface roughness that might perform as a kind of blackbody or Faraday cage effect. A multilayer coating structure was adopted for fulfilling the stringent requirements of the space. The surface of a standard silver plating was modified by a two-step treatment. First, a wet chemically etching process created a roughness of high aspect ratio, in the scale of microns. Secondly, the surface was coated with a protective 2 μm overlayer of gold, using magnetron sputtering. This anti-multipactor coating has been tested on several types of K{sub u}-band WR75 waveguide transformers and band-pass filters, with excellent results. The multipactor effect was suppressed for two waveguides, even when applying the maximum available power levels. As for the other final four, the increase of multipactor power level was in the range of 4–6 dB. These results were obtained after more than one year of air exposure. In spite of the strong roughness, the insertion losses were diminished by 25% with respect to the values attained in the tests of the standard anti-multipactor coating, Alodine.

  5. Tryptophan-Assisted Synthesis Reduces Bimetallic Gold/Silver Nanoparticle Cytotoxicity and Improves Biological Activity

    Igor O. Shmarakov


    Full Text Available Aiming to reduce the potential in vivo hepato-and nephrotoxicity of Ag/Au bimetallic nanoparticles (NPs stabilized by sodium dodecyl sulphate (SDS, an approach involving a simultaneous reduction of silver nitrate and tetrachlorauratic acid using tryptophan (Trp as a reducing/stabilizing agent was applied during NP synthesis. The obtained Ag/Au/Trp NPs (5–15 nm sized were able to form stable aggregates with an average size of 370–450 nm and were potentially less toxic than Ag/Au/SDS in relation to a mouse model system based on clinical biochemical parameters and oxidative damage product estimation. Ag/Au/Trp NPs were shown to exhibit anticancer activity in relation to a Lewis lung carcinoma model. The data generated from the present study support the fact that the use of tryptophan in NP synthesis is effective in attenuating the potential hepatotoxicity and nephrotoxicity of NPs during their in vivo application.

  6. Tryptophan-Assisted Synthesis Reduces Bimetallic Gold/Silver Nanoparticle Cytotoxicity and Improves Biological Activity

    Igor O. Shmarakov


    Full Text Available Aiming to reduce the potential in vivo hepato-and neph‐ rotoxicity of Ag/Au bimetallic nanoparticles (NPs stabi‐ lized by sodium dodecyl sulphate (SDS, an approach involving a simultaneous reduction of silver nitrate and tetrachlorauratic acid using tryptophan (Trp as a reduc‐ ing/stabilizing agent was applied during NP synthesis. The obtained Ag/Au/Trp NPs (5-15 nm sized were able to form stable aggregates with an average size of 370-450 nm and were potentially less toxic than Ag/Au/SDS in relation to a mouse model system based on clinical biochemical param‐ eters and oxidative damage product estimation. Ag/Au/Trp NPs were shown to exhibit anticancer activity in relation to a Lewis lung carcinoma model. The data generated from the present study support the fact that the use of tryptophan in NP synthesis is effective in attenuating the potential hepatotoxicity and nephrotoxicity of NPs during their in vivo application.

  7. Detection of Glucose Based on Gold & Silver Nanoparticles using Z-scan Technique

    Abdulwahab, Fatema


    Diabetes is a common chronic disease, characterized by defects in insulin action, secretion or both causing hyperglycemia. Diabetes can have serious long-term complications as it important to control blood glucose levels. Chemical and optical methods are used mainly in measuring glucose levels. Chemical methods require drawing blood several times a day which is uncomfortable for the patient. Optical sensor measurements are affected by physical and chemical parameters and environmental changes...

  8. Protein retention on plasma-treated hierarchical nanoscale gold-silver platform

    Fang, Jinghua; Levchenko, Igor; Mai-Prochnow, Anne; Keidar, Michael; Cvelbar, Uros; Filipic, Gregor; Han, Zhao Jun; Ostrikov, Kostya (Ken)


    Dense arrays of gold-supported silver nanowires of about 100 nm in diameter grown directly in the channels of nanoporous aluminium oxide membrane were fabricated and tested as a novel platform for the immobilization and retention of BSA proteins in the microbial-protective environments. Additional treatment of the silver nanowires using low-temperature plasmas in the inductively-coupled plasma reactor and an atmospheric-pressure plasma jet have demonstrated that the morphology of the nanowire array can be controlled and the amount of the retained protein may be increased due to the plasma effect. A combination of the neutral gold sublayer with the antimicrobial properties of silver nanowires could significantly enhance the efficiency of the platforms used in various biotechnological processes. PMID:26307515

  9. Fitting the optical constants of gold, silver, chromium, titanium, and aluminum in the visible bandwidth

    Barchiesi, Dominique; Grosges, Thomas


    The fitting of metal optical properties is a topic that has applications in advanced simulations of spectroscopy, plasmonics, and optical engineering. In particular, the finite difference time domain method (FDTD) requires an analytical model of dispersion that verifies specific conditions to produce a full spectrum in a single run. Combination of Drude and Lorentz models, and Drude and critical points models, are known to be efficient, but the number of parameters to be adjusted for fitting data can prevent accurate results from simulated annealing or Nelder-Mead. The complex number relative permittivities of Au, Ag, Al, Cr, and Ti from either Palik or Johnson and Christy experimental data in the visible domain of wavelengths are successfully fitted by using the result of the particle swarm optimization method with FDTD constraint, as a starting point for the Nelder-Mead method. The results are well positioned compared to those that can be found in the literature. The results can be used directly for numerical simulations in the visible domain. The method can be applied to other materials, such as dielectrics, and to other domain of wavelengths.

  10. Water, mineral waters and health.

    Petraccia, Luisa; Liberati, Giovanna; Masciullo, Stefano Giuseppe; Grassi, Marcello; Fraioli, Antonio


    The authors focus on water resources and the use of mineral waters in human nutrition, especially in the different stages of life, in physical activity and in the presence of some morbid conditions. Mineral water is characterized by its purity at source, its content in minerals, trace elements and other constituents, its conservation and its healing properties recognized by the Ministry of Health after clinical and pharmacological trials. Based on total salt content in grams after evaporation of 1l mineral water dried at 180 degrees C (dry residues), mineral waters can be classified as: waters with a very low mineral content, waters low in mineral content, waters with a medium mineral content, and strongly mineralized waters. Based on ion composition mineral waters can be classified as: bicarbonate waters, sulfate waters, sodium chloride or saltwater, sulfuric waters. Based on biological activity mineral waters can be classified as: diuretic waters, cathartic waters, waters with antiphlogistic properties. Instructions for use, doses, and current regulations are included.

  11. Epithermal Ageing Mechanism of Gussasphalt

    HAO Zengheng; TAN Yiqiu; ZHANG Xiaoning; ZHANG Feng


    The normal asphalt index test,DSR test,FTIR and the GPC distribution analysis of molecular weight on the extraction and recovery of asphalt of the gussasphalt,SMA extraction and recovery of asphalt and the rotary-thin-film-oven-aged asphalt above 240℃were introduced.The results indicate the rutting factor and fatigue factor of the extraction and recovery of asphalt of the gussasphalt are greatly improved,and an obvious absorption peak of carbonyl and a further decrease of the SBS molecular weight of the gussasphalt are found.

  12. Strategic Minerals of India

    D. N. Wadia


    Full Text Available The state of disequilibrium in the country's mineral economy may not be harmful in time of international peace, but is a source of double danger to national security in a war emergency, when imports of essential commodities, e.g., petroleum may be jeopardised and the off-take of credit earning exports may be stopped. A healthy economy can be achieved by balancing as near as possible, the surpluses against deficits through building up civilian industrial power of production of substitute for some deficient and sub-marginal commodities and stockpiling of others.

  13. Mineral mining installation

    Plevak, L.; Weirich, W.


    A longwall mineral mining installation has a longwall conveyor and a plurality of roof support units positioned side-by-side at the goaf side of the conveyor. The hydraulic appliances of the roof support units, such as their hydraulic props, hydraulic advance rams and hydraulic control valves, are supplied with pressurized hydraulic fluid from hydraulic supply lines which run along the goaf side of the conveyor. A plurality of flat, platelike intermediate members are provided at the goaf side of the conveyor. These intermediate members are formed with internal ducts for feeding the hydraulic fluid from the supply lines to the hydraulic appliances of the roof support units.

  14. Reinforcing the mineral layer

    Pishchulin, V.V.; Kuntsevich, V.I.; Seryy, A.M.; Shirokov, A.P.


    A way of reinforcing the mineral layer includes drilling holes and putting in anchors that are longer than the width of the layer strip being extracted. It also includes shortening the anchors as the strip is mined and reinforcing the remaining part of the anchor in the mouth of the hole. To increase the productivity and safety of the work, the anchors are shortened by cutting them as the strip is mined and are reinforced through wedging. The device for doing this has auxilliary lengthwise grooves in the shaft located along its length at an interval equal to the width of the band being extracted.

  15. Mineral fibres and cancer.

    McDonald, J C


    A synthesis is presented of the salient findings to date from laboratory and epidemiological research, on the health effects of asbestos and other natural and man-made mineral fibres. Experimental evidence suggests that all mineral fibres are capable of causing fibrosis and malignancy, with chrysotile at least as pathogenic as other fibres. However, penetration, retention and phagocytosis are affected by size and shape and reactivity and durability by physico-chemical properties. Thus it is not surprising that in man the results of exposure vary considerably with fibre type and industrial process. A considerable body of evidence suggests that chrysotile has seldom, if ever, caused peritoneal mesothelioma and that the great majority of pleural mesotheliomas are also attributable to crocidolite or amosite. Without more reliable information on intensity and duration of exposure by fibre type, the epidemiological evidence on this point cannot be wholly conclusive. There are stronger grounds from a limited number of cohort studies for believing that in relation to estimated exposure, the risk of lung cancer has been much higher in textile plants than in fibre production or in the manufacture of friction products, with asbestos-cement plants somewhere in between. The data on man-made fibre production remains equivocal. It is concluded that attempts to regulate asbestos without regard for fibre type, although perhaps adequate for lung cancer and fibrosis, may do little to reduce the risk of mesothelioma. The search for safe fibre substitutes for asbestos will remain difficult until the parameters of pathogenicity are better understood.

  16. Resolving the Distribution of Energy Critical Elements in Ore Systems through in situ Chemical mapping of Mineral Phases

    McClenaghan, Sean H.


    The mineral sphalerite is found in a wide-range of ore forming conditions including sedimentary and volcanogenic massive sulphides, as well as epigenetic mineralization associated with intrusive settings such as porphyries, skarns and epithermal veins. Sphalerite is a known host for In, Sn, Ge, Te, and Ga; these represent valuable commodities increasing the value of Zn production worldwide. These elements along with their deleterious counterparts Se, Hg, Tl, and Cd can reveal much about the genesis and evolution of a mineralizing system. From the standpoint of understanding the genesis of various ore systems, mineral chemistry, in particular the accommodation of trace elements in the sphalerite structure, is an ideal proxy for comparing both inter- and intra-deposit variations in hydrothermal geochemistry as well as enabling broad comparisons across a wide spectrum of mineral deposit types. The mineral chemistry of sphalerite will often differ between deposits of an ore district and can even exhibit considerable variability across individual mineral grains in response to evolving hydrothermal fluids and distinct fluid sources. Recent improvements in the field of in situ microanalysis have coupled advances in ICP-MS technology with newer classes of UV Excimer lasers and sample cells with smaller active volumes. This has effectively decreased the amount of ablated material required for analysis, allowing for more discrete analyses and permitting micro-chemical mapping at much smaller scales (ICP-MS analyses of sphalerite from epigenetic veins of the Leinster Batholith in Ireland have revealed anomalous values of ECE's, specifically In, Ga, and Ge; element maps (raster analysis) display a strong zonation of ECE's, which correspond to oscillatory growth and sectoral zoning within grains. The zonation of trace elements across several generations of sphalerite indicates highly variable sphalerite chemistry in response to evolving hydrothermal conditions. It is important

  17. Spectroscopic characterization of manganese minerals

    Lakshmi Reddy, S.; Padma Suvarna, K.; Udayabhaska Reddy, G.; Endo, Tamio; Frost, R. L.


    Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals.

  18. Spectroscopic characterization of manganese minerals.

    Lakshmi Reddy, S; Padma Suvarna, K; Udayabhaska Reddy, G; Endo, Tamio; Frost, R L


    Manganese minerals ardenite, alleghanyite and leucopoenicite originated from Madhya Pradesh, India, Nagano prefecture Japan, Sussex Country and Parker Shaft Franklin, Sussex Country, New Jersey respectively are used in the present work. In these minerals manganese is the major constituent and iron if present is in traces only. An EPR study of on all of the above samples confirms the presence of Mn(II) with g around 2.0. Optical absorption spectrum of the mineral alleghanyite indicates that Mn(II) is present in two different octahedral sites and in leucophoenicite Mn(II) is also in octahedral geometry. Ardenite mineral gives only a few Mn(II) bands. NIR results of the minerals ardenite, leucophoenicite and alleghanyite are due to hydroxyl and silicate anions which confirming the formulae of the minerals. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Geology, alteration, mineralization, petrogenesis, geochronology, geochemistry and airborne geophysics of Kuh Shah prospecting area, SW Birjand

    Maryam Abdi


    Full Text Available The Kuh Shah prospecting area is located in Tertiary volcano-plutonic belt of the Lut Block. More than seventeen subvolcanic intermediate to acidic intrusive rocks, diorite to syenite in composition, were identified in the study area. The intrusions are related to hydrothermal alteration zones and contain argillic, propylitic, advanced argillic, silicified, quartz-sericite-pyrite, gossan and hydrothermal breccia which overprinted to each other and are accompanied by weathering which made it complicated to distinguish zoning. Mineralization is observed as sulfide (pyrite and rare chalcopyrite, disseminated Fe-oxides and quartz-Fe-oxide stockwork veinlets. Intrusive rocks are metaluminous, calc-alkaline with shoshonitic affinity with high values of magnetic susceptibility. The Kuh Shah intrusive rocks are classified as magnetite-series of oxidant I-type granitoids. Based on zircon U–Pb age dating, the age of these granitoid rocks is 39.7± 0.7 Ma (Middle Eocene. The radioisotope data (initial 87Sr/86Sr and 143Nd/144Nd ratios as well as εNd and geochemical data suggest that the Kuh Shah granitoid rocks formed from depleted mantle in a subduction-related magmatic arc setting. Geochemical anomalies of elements such as Cu, Au, Fe, Pb, Zn, As, Sb, Mo, Bi, Hg and also Mn, Ba, Te and Se, correlated with quartz-sericite-pyrite, gossan-stockwork-hydrothermal breccias, irregular silicified bodies and advanced argillic hydrothermal alteration zones. Geophysical anomalies correlated with hydrothermal alteration and mineralization zones. The interpretation of the results represents complex patterns of sub-circular to ellipsoid shape with north-east to south-west direction. These evidences are similar to the other for known Cu-Au porphyry and Au-epithermal systems in Iran and worldwide.

  20. Radioactivity of phosphate mineral products

    Mitrović Branislava; Vitorović Gordana; Stojanović Mirjana; Vitorović Duško


    The phosphate industry is one of the biggest polluters of the environment with uranium. Different products are derived after processing phosphoric ore, such as mineral and phosphate fertilizers and phosphate mineral supplements (dicalcium-and monocalcium phosphate) for animal feeding. Phosphate mineral additives used in animal food may contain a high activity of uranium. Research in this study should provide an answer to the extent in which phosphate minera...

  1. The characteristics, origins, and geodynamic settings of supergiant gold metallogenic provinces

    Robert; Kerrich[1; Richard; Goldfarb[2; David; Groves[3; Steven; Garwin[4


    There are six distinct classes of gold deposits, each represented by metallogenic provinces, having 100’s to > 1 000 tonne gold production. The deposit classes are: (1) erogenic gold; (2) Carlin and Carlin-like gold deposits; (3) epithermal gold-silver deposits; (4) copper-gold porphyry deposits; (5) iron-oxide copper-gold deposits; and (6) gold-rich volcanic hosted massive sul-fide (VMS) to sedimentary exhalative (SEDEX) deposits. This classification is based on ore and alteration mineral assemblages; ore and alteration metal budgets; ore fluid pressure(s) and compositions; crustal depth or depth ranges of formation; relationship to structures and/or magmatic intrusions at a variety of scales; and relationship to the P-T-t evolution of the host terrane. These classes reflect distinct geodynamic settings. Orogenic gold deposits are generated at mid-crustal (4-16 km) levels proximal to terrane boundaries, in transpressional subduction-accretion complexes of Cordilleran style erogenic belts; other orogeni

  2. Protein- mediated enamel mineralization

    Moradian-Oldak, Janet


    Enamel is a hard nanocomposite bioceramic with significant resilience that protects the mammalian tooth from external physical and chemical damages. The remarkable mechanical properties of enamel are associated with its hierarchical structural organization and its thorough connection with underlying dentin. This dynamic mineralizing system offers scientists a wealth of information that allows the study of basic principals of organic matrix-mediated biomineralization and can potentially be utilized in the fields of material science and engineering for development and design of biomimetic materials. This chapter will provide a brief overview of enamel hierarchical structure and properties as well as the process and stages of amelogenesis. Particular emphasis is given to current knowledge of extracellular matrix protein and proteinases, and the structural chemistry of the matrix components and their putative functions. The chapter will conclude by discussing the potential of enamel for regrowth. PMID:22652761

  3. Mineralization by nanobacteria

    Kajander, E. Olavi; Bjorklund, Michael; Ciftcioglu, Neva


    Nanobacteria are the smallest cell-walled bacteria, only recently discovered in human and cow blood and in commercial cell culture serum. In this study, we identified with energy-dispersive x-ray microanalysis and chemical analysis that all growth phases of nanobacteria produce biogenic apatite on their cell envelope. Fourier transform IR spectroscopy revealed the mineral as carbonate apatite. Previous models for stone formation have lead to a hypothesis that an elevated pH due to urease and/or alkaline phosphatase activity are important lithogenic factors. Our results indicate that carbonate apatite can be formed without these factors at pH 7.4 at physiological phosphate and calcium concentrations. Due to their specific macromolecules, nanobacteria can produce apatite very efficiency in media mimicking tissue fluids and glomerular filtrate and rapidly mineralizing most of available calcium and phosphate. This can be also monitored by (superscript 85)Sr incorporation and provides a unique model for in vitro studies on calcification. Recently, bacteria have been implicated in the formation of carbonate (hydroxy)fluorapatite in marine sediments. Apatite grains are found so commonly in sedimentary rocks that apatite is omitted in naming the stone. To prove that apatite and other minerals are formed by bacteria would implicate that the bacteria could be observed and their actions followed in stones. We have started to approach this in two ways. Firstly, by the use of sensitive methods for detecting specific bacterial components, like antigens, muramic acid and nucleic acids, that allow for detecting the presence of bacteria and, secondly, by follow-up of volatile bacterial metabolites observed by continuous monitoring with ion mobility spectrometry, IMCELL, working like an artificial, educatable smelling nose. The latter method might allow for remote real time detection of bacterial metabolism, a signature of life, in rocks via fractures of drillholes with or without

  4. Mining activities and arsenic in a Baja California Sur watershed

    Alejandro Naranjo-Pulido; Alfredo Ortega-Rubio; Baudillo Acost-Vargas; Lia Rodriguez-Mendez; Marcos Acevedo-Beltran; Cerafina Arguelles-Mendez


    Mining is one of the most important sources of income for the Baja California Sur state. This state is the second most important area for mineral (gold, silver, copper) and non-mineral (salt) mining activities in the Mexican Republic. In the San Antonio-El Triunfo region, mineral-mining activities flourished during the 19th century. Tons of debris containing a high...

  5. 77 FR 56273 - Conflict Minerals


    ... opportunity to improve a company's existing risk management and supply chain management, stimulating... Minerals Already in the Supply Chain a. Proposed Rules b. Comments on the Proposed Rules c. Final Rule 6... Content and Supply Chain Due Diligence 1. Content of the Conflict Minerals Report a. Proposed Rules...

  6. Minerals From the Marine Environment

    Cruickshank, Michael J.

    The current interest in minerals centering on, among other things, potential shortages, long-term needs, and deep seabed nodules, accentuates the usefulness and timeliness of this little book authored by a former chairman of the British National Environmental Research Council.In less than 100 pages, the author puts into perspective the potential for producing minerals from offshore areas of the world. After introducing the reader to the ocean environment and the extraordinary variety of the nature of the seabed, the author describes in some detail the variety of minerals found there. This is done in seven separate chapters entitled ‘Bulk and Non-Metallic Minerals From the Seas’ ‘Metals From the Shallow Seas’ ‘Metals From the Deep Oceans’ ‘Minerals From Solution’ ‘Oil and Gas from the Shallow Seas’ ‘Oil and Gas From Deep Waters’ and ‘Coal Beneath the Sea.’ The remaining chapters give a brief regional review of marine minerals distribution for eight areas of significant socioeconomic structure, and a short recapitulation of special problems of mineral recovery in the marine environment including such matters as the effect of water motion on mineral processing and of international law on investments. Glossaries of geological periods and technical terms, a short list of references, and an index complete the work.

  7. Mineral Atlas of the World


    In 1997 the mineral resources of Europe and neighbouring countries were presented as a printed map and a book of exhaustive information and references. This was the first published map inventory of mineral deposits from all parts of the formerly politically divided Europe (East and West), measured and evaluated according to identical geological and mining standards.

  8. A Mineral Processing Field Course

    Carmody, Maurice


    This article describes a field course in Cornwall looking at mineral processing with the focus on the chemistry involved. The course was split into two parts. The first looked at tin mining based around Penzance. This involved visiting mines, hunting for mineral samples, carrying out a stream survey and visiting the Camborne School of Mines…

  9. Geotechnical Description of Mineral Deposits

    Sasvári Tibor


    Full Text Available Performing various mineral deposits extraction methods requires thorough knowledge of the rock masses` geomechanical parameters. In the geotechnical description of mineral deposits there is proposed a methodical approarch at the collection, registration, and evaluation of rock masses` geological properties for geotechnics being applied within the mining industry.

  10. Plant macro- and micronutrient minerals

    All plants must obtain a number of inorganic mineral elements from their environment to ensure successful growth and development of both vegetative and reproductive tissues. A total of fourteen mineral nutrients are considered to be essential. Several other elements have been shown to have beneficia...

  11. 75 FR 80947 - Conflict Minerals


    ... violence in the eastern Democratic Republic of the Congo, particularly sexual- and gender-based violence... conflict free,'' the facilities used to process the conflict minerals, the country of origin of the conflict minerals, and ``the efforts to determine the mine or location of origin with the greatest...

  12. 30 CFR 57.5070 - Miner training.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Miner training. 57.5070 Section 57.5070 Mineral... Agents, and Diesel Particulate Matter Diesel Particulate Matter-Underground Only § 57.5070 Miner training. (a) Mine operators must provide annual training to all miners at a mine covered by this part who...

  13. Formation Epoch of the South Tiegelong Supelarge Epithermal Cu (Au-Ag) Deposit in Tibet and Its Geological Implications%西藏铁格隆南超大型浅成低温热液铜(金、银)矿床的形成时代及其地质意义

    方向; 卫鲁杰; 张志; 杨欢欢; 高轲; 唐攀; 唐菊兴; 宋杨; 杨超; 丁帅; 王艺云; 王勤; 孙兴国; 李玉彬


    铁格隆南(荣那)矿床位于西藏班公湖—怒江成矿带西段的多龙整装勘查区内,是西藏首例超大规模的浅成低温热液-斑岩型Cu(Au、Ag)矿床。目前,矿床的勘查工作和科学研究正同时展开,本文采用锆石U-Pb、辉钼矿 Re-Os 同位素定年技术,结合系统的钻孔地质编录,对编录中新发现的含矿石英闪长玢岩和辉钼矿进行了高精度同位素测年。石英闪长玢岩LA-ICP-MS锆石U-Pb模式年龄为(120.2±1.0) Ma;辉钼矿Re-Os同位素测年的模式年龄分布在117.8~119.4 Ma范围内,平均模式年龄为(118.5±0.8) Ma,等时线年龄为(119.0±1.4) Ma(MSWD=0.34)。成岩成矿年龄近于一致,成矿略晚于成岩年龄,表明二者属于同一斑岩-浅成低温热液成矿系统。辉钼矿187Re 的含量分布于230.47~1226.6μg/g,指示成矿物质具幔源特征,暗示铁格隆南巨量金属物质的聚集可能与壳幔边界岩浆作用有关。对比研究表明,铁格隆南成矿作用与多不杂、波龙铜(金)矿床一同受控于统一的构造-岩浆成矿系统,该系统的形成无疑与早白垩世班公湖—怒江洋盆向北俯冲有关。%The South Tiegelong (Rongna) deposit, the first superlarge epithermal porphyry Cu (Au, Ag) deposit discovered in Tibet, is situated in the Duolong ore district along the west segment of the Bangong Co–Nujiang River metallogenic belt of Tibet. Both the exploration work and the scientific study of this deposit are being carried out at present. In combination with scientific geological logging, the authors applied the zircon U-Pb and molybdenite Re-Os isotopic dating to the newly found mineral-bearing quartz diorite porphyry and molybdenite. The LA-ICP-MS zircon U-Pb dating of the porphyry yielded a petrogenic age of (120.2±1.0) Ma, and the Re-Os isotopic model ages of molybdenite are distributed in the range of 117.8~119.4 Ma, which vary limitedly with an average model age of (118.45±0.76) Ma. The Re-Os isochron age

  14. Mineral mining installation

    Becker, K.; Rosenberg, H.; Weirich, W.


    A longwall mineral mining installation has a conveyor and a plurality of roof support units positioned side-by-side on the goaf side of the conveyor. Each roof support unit has a roof shield having an advanceable shield extension. Each unit has a first hydraulic ram for extending its shield extension, and a second hydraulic ram for advancing the conveyor. The extension of each first ram is controlled in dependence upon the retraction of one of the second rams (Either the second ram of the same unit or that of an adjacent unit). This control is effected by controlling the supply of pressurized hydraulic fluid to the first rams. In one embodiment this is carried out by a control valve which has a spring-loaded plunger which engages with a series of equispaced cams on the movable cylinder of the associated second ram. In another embodiment, the piston rods of the rams are provided with series of equispaced magnets. The cylinders of the rams are provided with sensors, which sense the magnets and generate control signals. A control box is provided to direct the control signals to control valves associated with the rams, so that the first rams are extended by the same distance as that through which the second rams are retracted.

  15. Mineral mining installation

    Weirich, W.


    A longwall mineral mining installation has a conveyor and a plurality of roof support units positioned side-by-side on the goaf side of the conveyor. Each roof support unit has a roof shield having an advanceable shield extension. Each unit has a first hydraulic ram for extending its shield extension, and a second hydraulic ram for advancing the conveyor. The extension of each first ram is controlled in dependence upon the retraction of one of the second rams (either the second ram of the same unit or that of an adjacent unit). This control is effected by controlling the supply of pressurized hydraulic fluid to the first rams. In one embodiment this is carried out by a control valve which has a springloaded plunger which engages with a series of equispaced cams on the movable cylinder of the associated second ram. In another embodiment, the piston rods of the rams are provided with series of equispaced magnets. The cylinders of the rams are provided with sensors, which sense the magnets and generate control signals. A control box is provided to direct the control signals to control valves associated with the rams, so that the first rams are extended by the same distance as that through which the second rams are retracted.

  16. Cs-137 geochronology, epithermal neutron activation analysis, and principal component analysis of heavy metals pollution of the Black Sea anoxic continental shelf sediments

    Duliu, O. G.; Cristache, C.; Oaie, G.; Culicov, O. A.; Frontasyeva, M. V.


    Anthropogenic Cs-137 Gamma-ray Spectroscopy assay (GrSA) performed at the National Institute of Research and Development for Physics and Nuclear Engineering - Bucharest (Romania) in correlation with Epithermal Neutrons Activation Analysis (ENAA) performed at the Joint Institute of Nuclear Researches - Dubna (Russia) were used to investigate a 50 cm core containing unconsolidated sediments collected at a depth of 600 m off Romanian town of Constantza, located in the anoxic zone of the Black Sea Continental Shelf. A digital radiography showed the presence of about 265 distinct laminae, 1 to 3 mm thick, a fact attesting a stationary sedimentary process, completely free of bioturbation. After being radiographed, the core was sliced into 45 segments whose thickness gradually increased from 0.5 to 5 cm, such that the minimum thickness corresponded to the upper part of the core. From each segment two aliquots of about 0.5 g and 50 g were extracted for subsequent ENAA and Cs-137 GrSA. The Cs-137 vertical profile evidenced two maxima, one of them was very sharp and localized at a depth of 1 cm and the other very broad, almost undistinguished at about 8 cm depth, the first one being attributed to 1986 Chernobyl accident. Based on these date, we have estimated a sedimentation ratio of about 0.5 mm/year, value taken as reference for further assessment of recent pollution history. By means of ENAA we have determined the vertical content of five presumed pollutants, e.i. Zn, As, Br, Sn and Sb and of Sc, as natural, nonpolluting element. In the first case, all five elements presented a more or less similar vertical profile consisting of an almost exponential decrease for the first 10 cm below sediment surface followed by a plateau until the core base, i.e. 50 cm below surface, dependency better described by the equation: c(z) = c0 [1+k exp (-z/Z)] (1) where: where c(z) represents the concentration vertical profile; z represents depth (in absolute value); c0 represents the plateau

  17. The "chessboard" classification scheme of mineral deposits: Mineralogy and geology from aluminum to zirconium

    Dill, Harald G.


    metamorphic) and structures. Cross sections and images illustrate the common ore types of each commodity. Ore takes priority over the mineral. The minerals and host rocks are listed by their chemical and mineralogical compositions, respectively, separated from the text but supplemented with cross-references to the columns and lines, where they prevalently occur. A metallogenetic-geodynamic overview is given at the bottom of each column in the spreadsheet. It may be taken as the "sum" or the " mean" of a number of geodynamic models and ideas put forward by the various researchers for all the deposits pertaining to a certain clan of lithology or structure. This classical or conservative view of metallotects related to the common plate tectonic settings is supplemented by an approach taken for the first time for such a number of deposits, using the concepts of sequence stratigraphy. This paper, so as to say, is a "launch pad" for a new mindset in metallogenesis rather than the final result. The relationship supergene-hypogene and syngenetic-epigenetic has been the topic of many studies for ages but to keep them as separate entities is often unworkable in practice, especially in the so-called epithermal or near-surface/shallow deposits. Vein-type and stratiform ore bodies are generally handled also very differently. To get these different structural elements (space) and various mineralizing processes (time) together and to allow for a forward modeling in mineral exploration, architectural elements of sequence stratigraphy are adapted to mineral resources. Deposits are geological bodies which need accommodation space created by the environment of formation and the tectonic/geodynamic setting through time. They are controlled by horizontal to subhorizontal reference planes and/or vertical structures. Prerequisites for the deposits to evolve are thermal and/or mechanical gradients. Thermal energy is for most of the settings under consideration deeply rooted in the mantle. A

  18. Economic drivers of mineral supply

    Wagner, Lorie A.; Sullivan, Daniel E.; Sznopek, John L.


    The debate over the adequacy of future supplies of mineral resources continues in light of the growing use of mineral-based materials in the United States. According to the U.S. Geological Survey, the quantity of new materials utilized each year has dramatically increased from 161 million tons2 in 1900 to 3.2 billion tons in 2000. Of all the materials used during the 20th century in the United States, more than half were used in the last 25 years. With the Earth?s endowment of natural resources remaining constant, and increased demand for resources, economic theory states that as depletion approaches, prices rise. This study shows that many economic drivers (conditions that create an economic incentive for producers to act in a particular way) such as the impact of globalization, technological improvements, productivity increases, and efficient materials usage are at work simultaneously to impact minerals markets and supply. As a result of these economic drivers, the historical price trend of mineral prices3 in constant dollars has declined as demand has risen. When price is measured by the cost in human effort, the price trend also has been almost steadily downward. Although the United States economy continues its increasing mineral consumption trend, the supply of minerals has been able to keep pace. This study shows that in general supply has grown faster than demand, causing a declining trend in mineral prices.

  19. Glycine Polymerization on Oxide Minerals

    Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru


    It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH3 + group of adsorbed Gly to the nucleophilic NH2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

  20. Mineral mining machines

    Mc Gaw, B.H.


    A machine for mining minerals is patented. It is a cutter loader with a drum actuating element of the worm type equipped with a multitude of cutting teeth reinforced with tungsten carbide. A feature of the patented machine is that all of the cutting teeth and holders on the drum have the identical design. This is achieved through selecting a slant angle for the cutting teeth which is the mean between the slant angle of the conventional radial teeth and the slant angle of the advance teeth. This, in turn, is provided thanks to the corresponding slant of the holders relative to the drum and (or) the slant of the cutting part of the teeth relative to their stems. Thus, the advance teeth projecting beyond the surface of the drum on the face side and providing upper and lateral clearances have the same angle of attack as the radial teeth, that is, from 20 to 35 degrees. A series of modifications of the cutting teeth is patented. One of the designs allows the cutting tooth to occupy a varying position relative to the drum, from the conventional vertical to an inverted, axially projecting position. In the last case the tooth in the extraction process provides the upper and lateral clearances for the drum on the face side. Among the different modifications of the cutting teeth, a design is proposed which provides for the presence of a stem which is shaped like a truncated cone. This particular stem is designed for use jointly with a wedge which unfastens the teeth and is placed in a holder. The latter is completed in a transverse slot thanks to which the rear end of the stem is compressed, which simplifies replacement of a tooth. Channels are provided in the patented machine for feeding water to the worm spiral, the holders and the cutting teeth themselves in order to deal with dust.

  1. Mineral Commodity Profiles -- Rubidium

    Butterman, W.C.; Reese, R.G.


    Overview -- Rubidium is a soft, ductile, silvery-white metal that melts at 39.3 ?C. One of the alkali metals, it is positioned in group 1 (or IA) of the periodic table between potassium and cesium. Naturally occurring rubidium is slightly radioactive. Rubidium is an extremely reactive metal--it ignites spontaneously in the presence of air and decomposes water explosively, igniting the liberated hydrogen. Because of its reactivity, the metal and several of its compounds are hazardous materials, and must be stored and transported in isolation from possible reactants. Although rubidium is more abundant in the earth?s crust than copper, lead, or zinc, it forms no minerals of its own, and is, or has been, produced in small quantities as a byproduct of the processing of cesium and lithium ores taken from a few small deposits in Canada, Namibia, and Zambia. In the United States, the metal and its compounds are produced from imported raw materials by at least one company, the Cabot Corporation (Cabot, 2003). Rubidium is used interchangeably or together with cesium in many uses. Its principal application is in specialty glasses used in fiber optic telecommunication systems. Rubidium?s photoemissive properties have led to its use in night-vision devices, photoelectric cells, and photomultiplier tubes. It has several uses in medical science, such as in positron emission tomographic (PET) imaging, the treatment of epilepsy, and the ultracentrifugal separation of nucleic acids and viruses. A dozen or more other uses are known, which include use as a cocatalyst for several organic reactions and in frequency reference oscillators for telecommunications network synchronization. The market for rubidium is extremely small, amounting to 1 to 2 metric tons per year (t/yr) in the United States. World resources are vast compared with demand.

  2. Book review: Mineral resource estimation

    Mihalasky, Mark J.


    Mineral Resource Estimation is about estimating mineral resources at the scale of an ore deposit and is not to be mistaken with mineral resource assessment, which is undertaken at a significantly broader scale, even if similar data and geospatial/geostatistical methods are used. The book describes geological, statistical, and geostatistical tools and methodologies used in resource estimation and modeling, and presents case studies for illustration. The target audience is the expert, which includes professional mining geologists and engineers, as well as graduate-level and advanced undergraduate students.

  3. Evaluation and calibration of a pulsed neutron method for total hydrogen determination in mineral and concrete samples

    Bennun, L.; Santibanez, M. [Universidad de Concepcion, Laboratorio de Fisica Aplicada, Departamento de Fisica, P.O. Box 160c, Concepcion (Chile); Gomez, J. [Holcim (Costa Rica) S.A, Alajuela (Costa Rica); Santisteban, J.R. [Centro Atomico Bariloche e Instituto Balseiro, Bariloche Rio Negro (Argentina)


    We studied the feasibility of a nondestructive method to determine hydrogen concentrations in concrete and mineral samples. The amount of total hydrogen in the sample is directly related to the proportion of water included in the paste preparation; and also considers all subsequent processes which can add or remove hydrogen in a real sample (like rain, evaporation, etc.). The hydrogen proportion is a critical variable in the curing concrete process; its excess or deficiency impacts negatively in the quality of the final product. The proposed technique is based on a pulsed neutron source and the technical support of the time of flight, which allow discriminating epithermal neutrons interacting with hydrogen (inelastic scattering) from the elastic and quasi-isotropic scattering produced by other kinds of atoms. The method was externally calibrated in limestone rocks fragments (CaCO{sub 3}-main material used in cement fabrication) and in steel, allowing an easy retrieval of the required information. The technique's simplicity may facilitate the development of a mobile measuring device in order to make determinations ''in situ.'' In this paper, we describe the foundations of the proposed method and various analysis results. (orig.)

  4. Refractory, Abrasive and Other Industrial Mineral Operations

    Department of Homeland Security — This map layer includes refractory, abrasive, and other industrial minerals operations in the United States. The data represent commodities covered by the Minerals...

  5. VT Mineral Resources - MRDS Extract

    Vermont Center for Geographic Information — (Link to Metadata) MRDSVT is an extract from the Mineral Resources Data System (MRDS) covering the State of Vermont only. MRDS database contains the records provided...

  6. Nondigestible carbohydrates and mineral bioavailability.

    Greger, J L


    Generally, fiber and compounds associated with fiber in cereal products (e.g., phytates) have been found to reduce the apparent absorption of minerals (such as calcium, magnesium, zinc and manganese) in humans, livestock and animal models. The effects of "soluble" forms of fiber (specifically pectins, gums, resistant starches, lactulose, oligofructose and inulin) on mineral absorption are more difficult to characterize. The addition of these soluble forms of fiber has been found in various studies to add viscosity to the gut contents, promote fermentation and the production of volatile fatty acids in the cecum, have a trophic effect on the ceca of animals and increase serum enteroglucagon concentrations. Thus it is not surprising that the addition of soluble forms of fiber to diets often has been found to improve absorption of minerals. This may reflect absorption of electrolytes from the large intestine. Future work should address the mechanisms by which ingestion of nondigestible carbohydrates improves mineral absorption in humans.

  7. BET measurements: Outgassing of minerals

    Clausen, Liselotte; Fabricius, Ida Lykke


    Outgassing minerals at elevated temperatures prior to BET measurements can lead to phase changes, especially in the case of amorphous and poorly crystalline materials. In order to evaluate the applicability of the BET method when low outgassing temperatures are required, selected aquifer minerals...... were outgassed at different temperatures and for different times. The studied minerals are 2-line ferrihydrite, goethite, lepidocrocite, quartz, calcite, ®-alumina, and kaolinite. The results demonstrate that measured specific surface areas of iron oxides are strongly dependent on outgassing conditions...... because the surface area increased by 170% with increasing temperature. In the poorly crystalline minerals, phase changes caused by heating were observed at temperatures lower than 100±C. Therefore low outgassing temperatures are preferable for minimizing phase changes. As demonstrated in this study...

  8. Infrared spectra of mineral species

    Chukanov, Nikita V


    This book details more than 3,000 IR spectra of more than 2,000 mineral species collected during last 30 years. It features full descriptions and analytical data of each sample for which IR spectrum was obtained.



    <正>20111673 Cao Ban(Zhejiang Institute of Geological & Mineral Resources,Hangzhou 310007,China);Ma Jun Determination of 16 Polycyclic Aromatic Hydrocarbons in Groundwater by High Performance Liquid Chromatography with Fluorescence-Ultraviolet Detector(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(5),2010,p.539-542,2 illus.,4 tables,15 refs.)Key words:liquid chromatography,polycyclic aromatic hydrocarbons,fluorescence analysis

  10. Mineral resources of Vietnam

    Kušnír Imrich


    Full Text Available Vietnam je bohatý na nerastné suroviny, ktoré sa nachádzajú prevažne na severe krajiny. Ložiská bauxitov, fosfátov, vzácnych zemín (REE, majú svetový význam. Ale i zásoby celého radu ïalších surovín (ropy, uhlia, zlata, železných rúd, chromitu, cínu, ilmenitu, medi, grafitu, atï. sú významné, ekonomicky ažite¾né a ich potenciál je obrovský. Za uvedené nerastné bohatstvo je „zodpovednᓠrozmanitá geologická stavba krajiny. Taktiež i morfológia a klíma (vlhká, tropická prispeli ku vytvoreniu niektorých ložísk (bauxity v krasových priehlbniach, atï.. Súèasná produkcia, okrem ropy (3,5 Mt/rok, zahròuje: 10,7 Mt uhlia, 3,5 Mt chromitu, asi 1 000 kg zlata, grafitu, kaolínu a mnohé iné minerály. Napriek tomu, je banícky priemysel v porovnaní so surovinovou základòou slabo vyvinutý. K jeho rozvoju urèite prispeje i úèas zahranièných spoloèností, odnedávna prítomných pri prieskume a ažbe surovín urèených pre export. Okrem struèného úvodu do geológie krajiny, obsahuje tento èlánok krátky popis nerastného bohatstva Vietnamu.

  11. The Sarylakh and Sentachan gold-antimony deposits, Sakha-Yakutia: A case of combined mesothermal gold-quartz and epithermal stibnite ores

    Bortnikov, N. S.; Gamynin, G. N.; Vikent'eva, O. V.; Prokof'ev, V. Yu.; Prokop'ev, A. V.


    New mineralogical, thermobarometric, isotopic, and geochemical data provide evidence for long and complex formation history of the Sarylakh and Sentachan Au-Sb deposits conditioned by regional geodynamics and various types of ore mineralization, differing in age and source of ore matter combined in the same ore-localizing structural units. The deposits are situated in the Taryn metallogenic zone of the East Yakutian metallogenic belt in the central Verkhoyansk-Kolyma Fold Region. They are controlled by the regional Adycha-Taryn Fault Zone that separates the Kular-Nera Terrane and the western part of the Verkhoyansk Fold-Thrust Belt. The fault extends along the strike of the northwest-trending linear folds and is deep-rooted and repeatedly reactivated. The orebodies are mineralized crush zones accompanied by sulfidated (up to 100 m wide) quartz-sericite metasomatic rocks and replacing dickite-pyrophyllite alteration near stibnite veinlets. Two stages of low-sulfide gold-quartz and stibnite mineralization are distinguished. The formation conditions of the early milk white quartz in orebodies with stibnite mineralization at the Sarylakh and Sentachan deposits are similar: temperature interval 340-280°C, salt concentration in fluids 6.8-1.6 wt % NaCl equiv, fluid pressure 3430-1050 bar, and sodic bicarbonate fluid composition. The ranges of fluid salinity overlapped at both deposits. In the late regenerated quartz that attends stibnite mineralization, fluid inclusions contain an aqueous solution with salinity of 3.2 wt % NaCl equiv and are homogenized into liquid at 304-189°C. Syngenetic gas inclusions contain nitrogen 0.19 g/cm3 in density. The pressure of 300 bar is estimated at 189°C. The composition of the captured fluid is characterized as K-Ca bicarbonatesulfate. The sulfur isotopic composition has been analyzed in pyrite and arsenopyrite from ore and metasomatic zones, as well as in coarse-, medium-, and fine-grained stibnite varieties subjected to

  12. Application of MNSR Epithermal Neutron Activation Analysis in Determination of Geological Sample%微堆超热中子活化分析在地学样品测定中的应用

    姜怀坤; 徐卫东; 赵伟; 成学海; 姜云; 夏传波


    The miniature neutron source reactor (MNSR) is based on highly enriched uranium (235 U ) as fuel and light water as moderator .Because of a larger share of epithermal neutron and fast neutron in irradiation channel ,the reactor is suitable for epithermal neutron activation analysis (ENAA ) .In general neutron activation analysis the main component elements in complex geological samples such as aluminum ,sodium , iron and so on affect the determination accuracy of some target elements .In order to reduce the interference of the background of main component elements and improve the precision and detection limit of the target element ,the ENAA can be used in the test of geological samples .By using epithermal neutron irradiation channel made of cadmium , the Cd ratios of about 130 nuclides of 67 elements in the periodic table were measured . T he advantage factors of some elements and the interferences of uranium fission and (n , p) reaction in ENAA were discussed .The practical application of MNSR ENAA method in testing of geological sample was verified .The results show that more than 20 kinds of elements can be ascertained in the sample measuring by this method . The detection limit ,precision and accuracy are more significantly improved .The MNSR ENAA is a necessary and beneficial supplement of the conventional activation analysis method .%微型中子源反应堆(简称微堆)是以高浓铀(235 U )作燃料的轻水欠慢化型反应堆,辐照孔道内存在有较大份额的超热中子和快中子,适合进行超热中子活化分析(ENAA)的实验研究。地质样品成分复杂,在用普通的中子活化分析时,基体元素影响了部分元素的准确测定。为降低基体成分的本底干扰、改善目标元素的测量精密度和检出限,可采用超热中子活化分析的方法。本文利用微堆上安装的屏蔽材料为镉的超热中子辐照孔道,测定了元素周期表中67种元素的约130个核素的镉

  13. Defining reactive sites on hydrated mineral surfaces: Rhombohedral carbonate minerals

    Villegas-Jiménez, Adrián; Mucci, Alfonso; Pokrovsky, Oleg S.; Schott, Jacques


    Despite the success of surface complexation models (SCMs) to interpret the adsorptive properties of mineral surfaces, their construct is sometimes incompatible with fundamental chemical and/or physical constraints, and thus, casts doubts on the physical-chemical significance of the derived model parameters. In this paper, we address the definition of primary surface sites (i.e., adsorption units) at hydrated carbonate mineral surfaces and discuss its implications to the formulation and calibration of surface equilibria for these minerals. Given the abundance of experimental and theoretical information on the structural properties of the hydrated (10.4) cleavage calcite surface, this mineral was chosen for a detailed theoretical analysis of critical issues relevant to the definition of primary surface sites. Accordingly, a single, generic charge-neutral surface site ( tbnd CaCO 3·H 2O 0) is defined for this mineral whereupon mass-action expressions describing adsorption equilibria were formulated. The one-site scheme, analogous to previously postulated descriptions of metal oxide surfaces, allows for a simple, yet realistic, molecular representation of surface reactions and provides a generalized reference state suitable for the calculation of sorption equilibria for rhombohedral carbonate minerals via Law of Mass Action (LMA) and Gibbs Energy Minimization (GEM) approaches. The one-site scheme is extended to other rhombohedral carbonate minerals and tested against published experimental data for magnesite and dolomite in aqueous solutions. A simplified SCM based on this scheme can successfully reproduce surface charge, reasonably simulate the electrokinetic behavior of these minerals, and predict surface speciation agreeing with available spectroscopic data. According to this model, a truly amphoteric behavior is displayed by these surfaces across the pH scale but at circum-neutral pH (5.8-8.2) and relatively high ΣCO 2 (⩾1 mM), proton/bicarbonate co

  14. Study on mineral processing technology for abrasive minerals

    Hong, Seong Woong; Yang, Jung Il; Hwang, Seon Kook; Choi, Yeon Ho; Cho, Ken Joon; Shin, Hee Young [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)


    Buyeo Materials in Buyeogun, Choongnam province is a company producing feldspar concentrate, but does not yet utilize the garnet as abrasive material and other useful heavy minerals wasted out from the process of feldspar ore. The purpose of this study is to develop technology and process for the recovery of garnet concentrate. As results, the garnet is defined as ferro manganese garnet. The optimum process for recovery of garnet concentrate is to primarily concentrate heavy minerals from tailings of feldspar processing. And secondly the heavy minerals concentrated is dried and separated garnet concentrate from other heavy minerals. At this time, the garnet concentrate is yield by 0.176%wt from 0.31%wt of heavy minerals in head ore. The garnet concentrate contains 33.35% SiO{sub 2}, 12.20% Al{sub 2}O{sub 3}, 28.47% Fe{sub 2}O{sub 3}, 11.96% MnO. As for utilization of abrasive materials, a fundamental data was established on technology of grinding and classification. (author). 13 refs., 47 figs., 24 tabs.

  15. 用于硼中子俘获治疗的超热中子束理论设计%Theoretical design of an epithermal neutron beam for boron neutron capture therapy

    张晓敏; 潘洁; 宁静; 谢向东; 杨国山


    Objective To design a scheme of epithermal neutron beam used for boron neutron capture therapy (BNCT).Methods Based on Tsinghua University experimental reactor and its No.1 passage,five schemes comprised of moderate materials,absorbing materials of thermal neutron and γ shielding materials were designed according to different locations of materials placed in No.1 passage.To select a proper scheme from five schemes,the neutron fluence rate,the neutron dose rate and γ dose rate at exit of beam in each scheme were calculated with Monte Carlo simulating methods and then contrasted with BNCT technique criterion.Results The scheme of epithermal neutron beam meeting technical requirements of BNCT was obtained,in which the thickness of moderate material,absorbing materials of thermal neutron and γ shielding materials are 53.5 cm,2 mm and 9 cm,respectively.Conclusions The theoretical scheme could provide some reference to realize BNCT on reactor.%目的 设计用于硼中子俘获治疗(BNCT)的超热中子束理论方案.方法 基于清华大学试验核反应堆,以其1号孔道为材料布放孔道,设计了由慢化材料、热中子吸收材料、γ屏蔽材料组成,但材料布放位置具有差异的5种理论方案;利用蒙特卡罗(MC)模拟方法,分别计算5种方案束出口处的中子注量率、剂量率及γ剂量率值,通过与BNCT技术指标对比,从5种方案中选择一种合适的方案.结果 得到了一个符合BNCT各项技术指标的超热中子束理论方案,其慢化材料厚度为53.5 cm、热中子吸收材料厚度为2 mm、γ屏蔽材料厚度为9 cm.结论 本研究给出的超热中子束理论方案为基于反应堆实现BNCT提供一定的理论参考.

  16. The possibility existence of volatile compounds in the area of NSR S5 spot of local suppression of epithermal neutron flux in the South Pole region of the Moon.

    Feoktistova, Ekaterina


    6 statistically significant areas in which it was recorded a lower value of the flow of epithermal neutrons was found in the polar regions of the moon according to LEND: 5 areas are located in the south polar region (the area NSR S1 - 5 [1]) and one (area NSR N1[1]) to the north. One of these areas - the area NSR S5 - is located in the landing sector Luna - Globe mission [2], the launch of which is planned by Russian Space Agency in 2018. In this paper, we investigated the temperature regime, illumination conditions and the possibility of the existence of deposits of volatile compounds in this area. To study we selected a number of substances was detected in the LCROSS impact site in the crater Cabeus, particularly compounds such as H2O, CO2, SO2, CH3OH, NH3, C2H4, H2S, CH4 · 5.75H2O and CO · 5.75H2O [3]. We divided the area of NSR S5 spot into a grid with a number of elements. Step in longitude grid was 0.15 degrees, a step in latitude 0.05 degrees. The total number of the elements of the area of the crater is 36000. The height, slope and orientation of each element were calculated based on a LOLA DEM [4] using an algorithm described in [5]. Our results show that the compounds of deposits such as H2O, CO2, SO2, CH3OH, NH3, C2H4, H2S, CH4 · 5.75H2O and CO · 5.75H2O may exist in NSR S5. Thus, the local suppression the epithermal neutron flux in this region may be due to the presence of hydrogen-containing compounds deposits. [1] Mitrofanov et al. (2012) JGR 117, E003956 [2] Ivanov et al. (2014) Solar System Res. 48, 391 - 402 [3] Colaprete et al. (2010) Science 330, 463-468 [4] [5] Zevenbergen, L.W., Thorne (1987) Earth Surface Processes and Landforms 12(1), 47-56.

  17. GIS-based Stress Field Modeling of the North Arm of Sulawesi (NAoS) and its application in mineral prospectivity assessment

    Albert, Gáspár; Szentpéteri, Krisztián


    Remotely sensed and digital map data are useful sources for regional structural analysis, including stress calculations. If the type of a given fault is determined and is considered as Andersonian, and rather juvenile instead of a reactivated one, the tectonic stress can be calculated for each of the fault segments (Albert et al. 2016). The North Arm of Sulawesi, a west-east-trending land strip of the irregular shaped Sulawesi Island, is actively deforming and the upper plate tectonic setting is quite complex in this region since it is situated above a triple junction of the Eurasian, Pacific and Australian plates. The stress currently acting in this region not only creates neotectonics but triggers subduction-related volcanism shifting from west to east on the peninsula. The volcanic centers - adjacent to transfer faults and the colliding plates at depth - appear to be the most productive areas for epithermal-porphyry mineralization systems of economic potential (Szentpéteri et al. 2015). In this work we demonstrate how the derived stress field model helps to understand the location and clustering of various mineralization types in the NAoS. We examine if this method is applicable for mineral prospectively assessments. References Albert, G., Barancsuk, Á., and Szentpéteri, K., 2016, Stress field modelling from digital geological map data: Geophysical Research Abstracts, v. 18, EGU2016-14565. Szentpéteri, K., Albert, G., and Ungvári, Z., Plate tectonic - and stress field - modeling of the North Arm of Sulawesi, Indonesia, to better understand distribution of mineral deposits styles., in Proceedings SEG 2015 I World Class Ore Deposits: Discovery to Recovery, Wrest Point Convention Centre, Hobart, Australia, September 27 - 30. 2015.

  18. Mineral commodity profiles: nitrogen

    Kramer, Deborah A.


    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  19. [Mineral water as a cure].

    Nocco, Priska Binz


    The treatment of diseases with mineral spring water belongs to the oldest medical therapies. The "remedy" mineral water is therefore of importance also within the pharmacy. The present pharmacy historical work examines the impact of the use of mineral waters, as well as of their dried components, as therapeutic agents in the 19th and early 20th centuries, i.e. from approx. 1810 to 1930, as well as the contributions given by pharmacists in the development and analysis of mineral water springs. Beside these aspects, the aim here is also to describe the role played by pharmacists in the production of artificial mineral water as well as in the sale and wholesale of natural and artificial mineral water. In the first part of this work the situation in Switzerland and its surrounding countries, such as Germany, France, Italy and Austria, is discussed. The second part contains a case-study of the particular situation in the Canton Tessin. It is known from the scientific literature published at that time that information on mineral water was frequently reported. Starting from the beginning of the 19th century the number of such publications increased tremendously. The major part of them were publications in scientific journals or contributions to medical and pharmaceutical manuals and reference books. In particular the spa-related literature, such as spa-guides, was of growing interest to a broad public. The inclusion of monographs into the Swiss, the Cantonal as well the foreign pharmacopoeias granted a legal frame for the mineral waters and their dried components. These works are of major importance from a pharmacy historical standpoint and represent a unique proof of historical evidence of the old medicinal drug heritage. The most frequently used therapies based on mineral waters were drinking and bath cures. Several diseases, particularly those of a chronic character, were treated with mineral waters. The positive influence of these cures on the recovery of the patients

  20. Self-ordering and complexity in epizonal mineral deposits

    Henley, Richard W.; Berger, Byron R.


    Epizonal base and precious metal deposits makeup a range of familiar deposit styles including porphyry copper-gold, epithermal veins and stockworks, carbonate-replacement deposits, and polymetallic volcanic rock-hosted (VHMS) deposits. They occur along convergent plate margins and are invariably associated directly with active faults and volcanism. They are complex in form, variable in their characteristics at all scales, and highly localized in the earth’s crust.

  1. 21 CFR 573.680 - Mineral oil.


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Mineral oil. 573.680 Section 573.680 Food and... Listing § 573.680 Mineral oil. Mineral oil may be safely used in animal feed, subject to the provisions of this section. (a) Mineral oil, for the purpose of this section, is that complying with the...

  2. Effect of mineral processing wastewater on flotation of sulfide minerals

    CHEN Jian-ming; LIU Run-qing; SUN Wei; QIU Guan-zhou


    The effects of mineral processing wastewater on sulfide minerals were investigated by flotation, infrared spectrometry and electrochemistry test. The results show that lead-concentrate water can improve the flotation of galena, while the sulfur-concentrate water has negative effect on flotation of galena compared with distilled water. The flotation behavior of pyrite is contrary to that of galena in three kinds of water. Infrared spectra indicate that the residual collector in the lead-concentrate water is beneficial to the formation of lead xanthate on the surface of galena. Electrochemistry results indicate that electrochemistry reaction on galena surface has apparent change. The anode polarization is improved and cathode polarization is depressed.

  3. Prospects of gold mineralization in the Gilgit-Baltistan Province of Pakistan

    Shah, M. T.; Khan, S. D.; Tahirkheli, T.; Ahmad, L.; Miandad, S.; Rehman, A. U.; Ali, L.


    mainly pyrite and chalcopyrite with subordinate amount of bornite and tetrahedrite. Surface leaching of these phases to malachite, azurite and limonite is common. Quartz veining, silicification, carbonization and at places brecciation are the common features of these alteration zones. The concentrations of gold were found in the range of 3ppb to 112ppb, <5- 95ppb, 1ppb to 545ppb, 1ppb to 385 and 1ppb to 318ppb in the alteration zones of Golo Das, Bagrot valley, Shigri Bala, Machulu and Ranthak areas respectively. The barren rock samples have generally <5ppb gold. This is indicative of the multi-times enrichment of gold in the alteration zones. The sulfide mineralization along with gold in the alteration zones could be attributed to the hydrothermal/epithermal activity involving meteoric, igneous and or metamorphic fluid individually or mixture of these. The occurrence of dioritic intrusions (igneous fluid source) and the transitional dilated zones (metamorphic fluid source) on the major reactivated thrust fault (i.e., NSZ) in the vicinity of these alteration zones strengthen these observations. However, isotopic studies are underway to solve this problem. This study suggests that the alteration zones in the studied areas have the potential to be explored in detail for possible economical gold mineralization.

  4. Geology, mineralization and geochemistry of the Aqkand Cu occurrence (north of Zanjan, Tarom-Hashtjin zone

    Maryam Feyzi


    , fluorite and chlorite are present in the gangue minerals that represent vein-veinlet, breccia, vug infill, replacement, colloform, cockade, crustiform and plumose textures. Comparison of Chondrite normalized (Nakamura, 1974 REE patterns of Eocene fresh and barren andesitic basalt lavas, Oligocene rhyolitic-rhyodacitic lavas and the mineralized samples at Aqkand indicate that ore-forming fluids are probably related to Oligocene rhyolitic-rhyodacitic lavas. However, leaching of some elements from the host andesitic basalt lavas may have also been involved in mineralization. The geological, mineralogical, geochemical, textural and structural characteristics of the Aqkand occurrence reveals that copper mineralization at Aqkand is an example of epithermal base metal mineralization within the Tarom-Hashtjin zone. Acknowledgements The authors are grateful to the University of Zanjan Grant Commission for research funding. Mr. A.A. Atashnema is also appreciated for his help during the field work. Journal of Economic Geology reviewers and editor are also thanked for their constructive suggestions on alterations to the manuscript. References Davies, R.G., 1977. Geological map of Bandar-e-Anzali, scale 1:250,000. Geological Survey of Iran. Faridi, M. and Anvari, A., 2000. Geological map of Hashtjin, scale 1:100,000. Geological Survey of Iran. Hirayama, K., Samimi, M., Zahedi, M. and Hushmand-Zadeh, A., 1966. Geology of the Tarom District, Western Part (Zanjan area north-west Iran, Geological Survey of Iran, Tehran, Report 8, 31 pp. Nakamura, N., 1974. Determination of REE, Ba, Fe, Mg, Na and K in carbonaceous and ordinary Chondrites. Geochimica et Cosmochimica Acta, 38(5: 755–773.

  5. Clay minerals in pollution control

    Tateo, F. [Consiglio Nazionale delle Ricerche, Istituto di Ricerca sulle Argille, Tito Scalo, PZ (Italy)


    Clay minerals are fundamental constituents of life, not only as possible actors in the development of life on the Earth (Cairns-Smith and Hartman, 1986), but mainly because they are essential constituents of soils, the interface between the solid planet and the continental biosphere. Many, many authors have devoted themselves to the study of clays and clay minerals since the publication of the early modern studies by Grim (1953, 1962) and Millot (1964). In those years two very important associations were established in Europe (Association Internationale pour l'Etude des Argiles, AIPEA) and in the USA (Clay Mineral Society, CMS). The importance of these societies is to put together people that work in very different fields (agronomy, geology, geochemistry, industry, etc.), but with a common language (clays), very useful in scientific work. Currently excellent texts are being published, but introductory notes are also available on the web (Schroeder, 1998).

  6. Proton induced luminescence of minerals

    Calvo del Castillo, H.; Millan, A.; Calderon, T. [Depto. Geologia y Geoquimica, Universidad Autonoma de Madrid, Ctra. Colmenar, km. 15, 28049, Madrid (Spain); Beneitez, P. [Departamento Quimica Fisica Aplicada, Universidad Autonoma de Madrid Cantoblanco, Madrid (Spain); Ruvalcaba S, J.L. [lFUNAM, Circuito de la lnvestigacion Cientifica s/n, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)


    This paper presents a summary of Ionoluminescence (IL) for several minerals commonly found in jewellery pieces and/or artefacts of historical interest. Samples including silicates and non-silicates (native elements, halide, oxide, carbonate and phosphate groups) have been excited with a 1.8 MeV proton beam, and IL spectra in the range of 200- 900 nm have been collected for each one using a fiber optic coupled spectrometer. Light emissions have been related to Cr{sup 3+}, Mn{sup 2+} and Pr{sup 3+} ions, as well as intrinsic defects in these minerals. Results show the potential of IL for impurity characterization with high detection limits, local symmetry studies, and the study of the origin of minerals. (Author)

  7. Impact of mineral resource depletion

    Brent, AC


    Full Text Available In a letter to the editor, the authors comment on BA Steen's article on "Abiotic Resource Depletion: different perceptions of the problem with mineral deposits" published in the special issue of the International Journal of Life Cycle Assessment...



    20150874Chen Haidong(Inner Mongolia Institute of Geological Survey and Mineral Exploration,Hohhot 010010,China);Li Jiao Zircon U-Pb Dating of the Hypersthene-Plagioclase Granulite in Liangcheng Area of Central Inner Mongolia and Its Geological Significance(Geology in China,ISSN1000-3657,CN11-1167/P,41(4),2014,p.1136-1142,



    20152386 Hao Yuanfang(Shenyang Institute of Geology and Mineral Resources,CGS,Shenyang 110032,China);Xu Yingkui Determination of Calcium Oxide in Nickel Ores with EDTA Titration(Geology and Resources,ISSN1671-1947,CN21-1458/P,23(6),2014,p.580-582,2tables,6 refs.)



    <正>20131550 Bai Jinfeng(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China);Bo Wei Determination of 36Elements in Geochemical Samples by High Resolution Inductively Coupled Plasma-Mass Spectrometry(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,31(5),2012,p.814



    <正>20050704 Cheng Lin (Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China); Feng Songlin Analysis of Colored Elements in Ancient Colored Glaze by SRXRF (Rock and Mineral Analysis, ISSN0254-5357, CN11 -2131/TD, 23 (2), 2004, p. 113-116, 120, 3 illus. , 3 tables, 6 refs. )



    <正>20142093Chen Daohua(Guangzhou Marine Geological Survey,Guangzhou 510075,China);Diao Shaobo The Latest Progress of Geological Marine Testing Technology in China(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,32(6),2013,p.850-859,105refs.)Key words:chemical analysis,China



    <正>20070252 Chen Meilan (Biological and Environmental College, Zhejiang Shuren University, Hangzhou 310015, China); Li Li Study on Adsorption of Phenol by Modified Organobentonite (Rock and Mineral Analysis, ISSN0254-5357, CN11-2131/TD, 24(4), 2005, p.259-261, 267, 6 illus., 1 table, 11 refs.) Key words: bentonite, benzene, adsorption

  14. Leptin and bone mineral density

    Morberg, Cathrine M; Tetens, Inge; Black, Eva;


    Leptin has been suggested to decrease bone mineral density (BMD). This observational analysis explored the relationship between serum leptin and BMD in 327 nonobese men (controls) (body mass index 26.1 +/- 3.7 kg/m(2), age 49.9 +/- 6.0 yr) and 285 juvenile obese men (body mass index 35.9 +/- 5.9 kg...



    20160255 Wang Na(Tianjin Center of Geological Survey,China Geological Survey,Tianjin 300170,China);Teng Xinhua Determination of Low-Content Iron Carbonate in Stream Sediments by Flame Atomic Absorption Spectrometry with Aluminum Chloride Extraction(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,34(2),2015,p.229

  16. KeyPathwayMinerWeb

    List, Markus; Alcaraz, Nicolas; Dissing-Hansen, Martin;


    We present KeyPathwayMinerWeb, the first online platform for de novo pathway enrichment analysis directly in the browser. Given a biological interaction network (e.g. protein-protein interactions) and a series of molecular profiles derived from one or multiple OMICS studies (gene expression...



    <正>20140786Deng Zhenping(Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin 541004,China);Yang Wen-qiong Application of Stripping Voltammetry with a Solid Amalgam Electrode for Determination of Copper in a Tracer and Groundwater Tracing Experiment(Rock and Mineral Analy-

  18. Proceedings of XXIV international mineral processing congress

    Wang Dianzuo; Sun Chuan Yao; Wang Fu Liang; Zhang Li Cheng; Han Long (eds.)


    Topics covered in volume 1 include applied mineralogy, comminution, classification, physical separation, flotation chemistry, sulphide flotation, non-sulphide flotation and reagent in mineral industry. Volume 2 covers processing of complex ores, processing of industrial minerals and coal, solid liquid separation, dispersion and aggregation, process simulation, expert systems and control of mineral processing, biohydrometallurgy, and mineral chemical processing. Volume 3 contains powder technology, mineral materials, treatment and recycling for solid wastes, waste water treatment, secondary resource recovery, soil remediation, concentrator engineering and process design, and application of mineral processing in related industry. It includes a CD-ROM of the proceedings.

  19. U.S. Geological Survey Mineral Resources Program—Mineral resource science supporting informed decisionmaking

    Wilkins, Aleeza M.; Doebrich, Jeff L.


    The USGS Mineral Resources Program (MRP) delivers unbiased science and information to increase understanding of mineral resource potential, production, and consumption, and how mineral resources interact with the environment. The MRP is the Federal Government’s sole source for this mineral resource science and information. Program goals are to (1) increase understanding of mineral resource formation, (2) provide mineral resource inventories and assessments, (3) broaden knowledge of the effects of mineral resources on the environment and society, and (4) provide analysis on the availability and reliability of mineral supplies.

  20. Aggregate and Mineral Resources - INDUSTRIAL_MINERALS_POINTS_IN: Industrial Mineral Data in Indiana (Indiana Geological Survey, Point Shapefile)

    NSGIC GIS Inventory (aka Ramona) — INDUSTRIAL_MINERALS_POINTS_IN is a shapefile that shows the distribution of stratigraphic data for various industrial minerals in Indiana. These data were derived...

  1. Minería de datos con Oracle Data Miner

    Fernández Ruiz, Benjamín


    La intención del proyecto es mostrar las diferentes características que ofrece Oracle en el campo de la minería de datos, con la finalidad de saber si puede ser una plataforma apta para la investigación y la educación en la universidad. En la primera parte del proyecto se estudia la aplicación “Oracle Data Miner” y como, mediante un flujo de trabajo visual e intuitivo, pueden aplicarse las distintas técnicas de minería (clasificación, regresión, clustering y asociación). Para mostrar la ej...

  2. Tellurium-Gold Mineralization Related to Cryptoexplosive Breccias within Volcanic Pipe in Zhuojiazhuang Gold Deposit,Shandong Province, China

    Zeng Qingdong; Liu Tiebing; Shen Yuanchao; Li Guangming


    ,microcrystalline quartz-polymetal sulfides stage, quartz-adular stage and dickite stage. Wall rock alteration is characterized bysilicification, sericitization, adularization and fluoritization.The enrichment of tellurium may indicate that the ore-forming fluid was of a deep origin from upper mantle or lower crust. Mineral assemblage of microcrystalline quartz, fluorite, adularia and dickite suggest a relatively low-temperature forming condition. An extensive suite of elements, including Au, Ag, Te, Hg, Sb, As, Mo, F, Zn, and Tl, is significantly enriched in mineralized rocks. They can be geochemical indicators for exploration in the study area.Comprehensive studies show that the Zhuojiazhuang gold deposit is a type of sericite-adular gold deposit, belongs to epithermal gold deposits, or can be classified into alkali gold deposit series.

  3. Mineral operations outside the United States

    U.S. Geological Survey, Department of the Interior — Mineral facilities and operations outside the United States compiled by the National Minerals Information Center of the USGS. This representation combines source...

  4. Characterization of biological mineralization in vitro

    Huitema, L.F.A.


    Mineralization is an essential requirement for normal skeletal development, which is generally accomplished through the function of two cell types, osteoblasts and chondrocytes. Soft tissues do not mineralize under normal conditions, but under certain pathological conditions some tissues like articu

  5. Miscellaneous Industrial Minerals Operations - Direct Download

    U.S. Geological Survey, Department of the Interior — This map layer includes miscellaneous industrial minerals operations in the United States. The data represent commodities covered by the Minerals Information Team...

  6. Studies of mineralization in South African rivers

    Hall, GC


    Full Text Available Several South African rivers are polluted by mineral salts of diffuse source. This pollution can be related to geological phenomena and to irrigation practices. Mineralization is problematic in that it can render surface waters unsuitable...

  7. ARC Code TI: sequenceMiner

    National Aeronautics and Space Administration — The sequenceMiner was developed to address the problem of detecting and describing anomalies in large sets of high-dimensional symbol sequences. sequenceMiner works...

  8. Mineral Operations of Latin America and Canada

    U.S. Geological Survey, Department of the Interior — This data set consists of records for over 900 mineral facilities in Latin America and Canada. The mineral facilities include mines, plants, smelters, or refineries...



    The application of microbial technology to mineral processing has been reviewed with respect to the bioleaching of metals from minerals, the influence of biotreatment on flotation, the biobene ficiation of nonmetallic minerals, and the biotreatment for mine waste reclamation.The application of microbial technology to mineral processing has shown the advantages of high efficiency, low energy and reagent consumption, low capital and operating costs, and low pollution of the environment.

  10. Bolter miners for longwall development

    Leeming, J.; Flook, S. [Joy Mining Machinery Ltd., Nottingham (United Kingdom); Altounyan, P. [Rock Mechanics Technology Ltd., Derby (United Kingdom)


    Rapid entry drivage systems are now being applied in European mining conditions with major advantages, not only in terms of drivage rates, costs and longwall productivity, but also with improved safety. This is being achieved through the introduction of bolter miner systems in which the early installation of high strength rockbolts is fully integrated with the drivage system and all ancillary operations. These new systems are fully described with examples of applications in European conditions and procedures for design of rockbolt patterns. (orig.) [German] Schnelle Streckenvortriebssysteme, die jetzt unter typisch europaeischen Bergbaubedingungen eingefuehrt werden, bringen grosse Vorteile, nicht nur hinsichtlich einer Verbesserung der Vortriebsgeschwindigkeiten, Auffahrkosten und Strebleistungen, sondern auch aufgrund des erhoehten Sicherheitsniveaus. Der Erfolg dieses Vortriebsverfahrens kann auf die Einfuehrung des Bolter Miner Systems zurueckgefuehrt werden. (orig.)

  11. Borate Minerals and RNA Stability

    Ernesto Di Mauro


    Full Text Available The abiotic origin of genetic polymers faces two major problems: a prebiotically plausible polymerization mechanism and the maintenance of their polymerized state outside a cellular environment. The stabilizing action of borate on ribose having been reported, we have explored the possibility that borate minerals stabilize RNA. We observe that borate itself does not stabilize RNA. The analysis of a large panel of minerals tested in various physical-chemical conditions shows that in general no protection on RNA backbone is exerted, with the interesting exception of ludwigite (Mg2Fe3+BO5. Stability is a fundamental property of nucleic polymers and borate is an abundant component of the planet, hence the prebiotic interest of this analysis.

  12. Mineral bridges in nacre revisited

    Checa, Antonio G; Willinger, Marc-Georg


    We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200 nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (> 100 nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (< 60 nm), earlier reported to be mineral bridges, found to be such.



    <正>20101621 Chen Heping (Nanyang Geology Testing & Research Center of Henan Province, Nanyang 473000, China); Sha Yanmei Simultaneous Determination of Major and Minor Elements in Carbonates by Inductively Coupled Plasma-Atomic Emission Spectrometry with Multi-direction Viewing Mode (Rock and Mineral Analysis, ISSN0254-5357, CN11-2131/TD, 28(4), 2009, p.367-369, 5 tables, 10 refs.)



    <正>20070970 Cheng Jian(Center of Analysis and Testing,Hunan Zhuye Torch Metals Co., Ltd.,Zhuzhou 412004,China)Direct Deter- mination of Lead in Refined Indium by Flume Atomic Absorption Spectrometry (Rock and Mineral Analysis,ISSN 0254- 5357,CN11-2131/TD,25(1),2006,p.91 -92,94,1 illus.,7 tables,5 refs.) Key words:lead,atomic absorption



    <正>20122362 Cai Shuwei ( Nanjing Institute of Geology and Mineral Resources,Nanjing 210016,China );Zhu Jiaping Evaluating on Uncertainty of Determination of Manganese Contents in Groundwater by Inductively Coupled Plasma Atomic Emission Spectrometry ( Resources Survey & Environment,ISSN1671-4814,CN32-1640 / N,32 ( 4 ), 2011,p.307-310,2tables,8refs. ) Key words:inductively coupled plasma atomic emission spectroscopy,manganese

  16. Raising Environmental Awareness among Miners in Iran

    Mozaffari, Ezatollah


    Generation of waste is inevitable but controllable in minerals industry. The aim of this research is to find ways for raising environmental awareness among miners. Miners' attitude towards environmental mining has been investigated. A survey has been done collecting mine managers' point of view coupled with current trend on mine waste management…

  17. Mineralization potential of polarized dental enamel.

    Reina Tanaka

    Full Text Available BACKGROUND: Management of human teeth has moved from a surgical to a more conservative approach of inhibiting or preventing lesion progression. Increasing enamel mineralization is crucial in this regard. A potential difficulty is the preferential mineralization of the outermost portion of the enamel that can prevent overall mineralization. We describe a strategy for increasing the mineralization potential of dental enamel. METHODOLOGY/PRINCIPAL FINDINGS: Extracted human premolar teeth enamel (n = 5 were exposed to a high concentration of hydrogen peroxide with an energizing source. Samples were stored in artificial saliva at 37 degrees C for 1 wk. A desktop X-ray micro-CT system was used to evaluate the mineral density of samples. Mineral distribution was polarized between the lower and the higher mineralized portion of enamel by charged oxygen free radicals due to activation of permeated hydrogen peroxide. The kinetics of energy absorption in the deeper enamel region demonstrated improvement of preferential mineralization into the region without restricting overall mineralization of the enamel. Subsequent increasing mineralization, even in the dense mineralized outer portion of enamel, was also achieved. CONCLUSIONS/SIGNIFICANCE: This increased mineralization may promote resistance to acidic deterioration of the structure. The present study is one of the primary steps towards the development of novel application in reparative and restorative dentistry.

  18. Mineral zircon : A novel thermoluminescence geochronometer

    Van Es, HJ; Vainshtein, DI; De Meijer, RJ; Den Hartog, HW; Donoghue, JF; Rozendaal, A


    Mineral zircon contains trace amounts (typically 10-1000 ppm) of the alpha-emitters uranium and thorium, which irradiate this mineral internally. This outstanding feature of zircon turns out to be extremely useful when this mineral is applied as a thermoluminescence (TL) dating medium, because the b

  19. Sorption of pesticides to aquifer minerals

    Clausen, Liselotte; Fabricius, Ida Lykke


    This paper summarizes results from a work were the sorption of five pesticides on seven minerals were studied in order to quantify the adsorption to different mineral surfaces. Investigated mineral phases are: quartz, calcite, kaolinite, a-alumina, and three iron oxides (2-line ferrihydrite, goet...

  20. 43 CFR 8.5 - Mineral rights.


    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Mineral rights. 8.5 Section 8.5 Public... INTERIOR AND OF THE ARMY RELATIVE TO RESERVOIR PROJECT LANDS § 8.5 Mineral rights. Mineral, oil and gas rights will not be acquired except where the development thereof would interfere with project...

  1. Is Struvite a Prebiotic Mineral?

    Matthew A. Pasek


    Full Text Available The prebiotic relevance of mineral struvite, MgNH4PO4·6H2O, was studied experimentally as a phosphorylating reagent and, theoretically, to understand the geochemical requirements for its formation. The effectiveness of phosphorylation by the phosphate mineral, monetite, CaHPO4, was also studied to compare to the efficiency of struvite. The experiments focused on the phosphorylation reactions of the minerals with organic compounds, such as nucleosides, glycerol and choline chloride, and heat at 75 °C for about 7–8 days and showed up to 28% phosphorylation of glycerol. In contrast, the compositional requirements for the precipitation of struvite are high ammonium and phosphate concentrations, as well as a little Ca2+ dissolved in the water. Combined, these requirements suggest that it is not likely that struvite was present in excess on the early Earth to carry out phosphorylation reactions. The present study focuses on the thermodynamic aspects of struvite formation, complementing the results given by Orgel and Handschuh (1973, which were based on the kinetic effects.

  2. Is Struvite a Prebiotic Mineral?

    Gull, Maheen; Pasek, Matthew A.


    The prebiotic relevance of mineral struvite, MgNH4PO4·6H2O, was studied experimentally as a phosphorylating reagent and, theoretically, to understand the geochemical requirements for its formation. The effectiveness of phosphorylation by the phosphate mineral, monetite, CaHPO4, was also studied to compare to the efficiency of struvite. The experiments focused on the phosphorylation reactions of the minerals with organic compounds, such as nucleosides, glycerol and choline chloride, and heat at 75 °C for about 7–8 days and showed up to 28% phosphorylation of glycerol. In contrast, the compositional requirements for the precipitation of struvite are high ammonium and phosphate concentrations, as well as a little Ca2+ dissolved in the water. Combined, these requirements suggest that it is not likely that struvite was present in excess on the early Earth to carry out phosphorylation reactions. The present study focuses on the thermodynamic aspects of struvite formation, complementing the results given by Orgel and Handschuh (1973), which were based on the kinetic effects. PMID:25369744

  3. [Legal aspects of mineral waters].

    Callipo, C


    The Author takes up the subject of the report in order to carry out a comprehensive legal recognition of the mineral water regulations in Italy and emphasizes that in this field the results of scientific conclusions, or rather of the various scientific branches (medical hydrology, microbiology, chemics, hydrogeology, medical clinics, pharmacology, etc.) supply a cognitive support to the legislator and the substantial contents to the legal standards. He therefore illustrates the two main outlines of the rules, i.e. the hygienic sanitary one and the mineral one: such lay-out is subsequently related to the implementation of the Regions on one hand and to the enforcement of CEE-rules on the other. This has led to the fact that the hygienic-sanitary legislation was confirmed to the State while the mineral one was transferred to the Regions. After having shown up contrasts and expressed the necessity of clearness and uniformity of rules and criteria, the Author connects these requirements mainly with the implementation of hygienic-sanitary surveillance and consequently with the evaluation of the banal bacterical contents under the point of view of merit--i.e. the rules should include the probative results of science--as well as from a point of view of coordinated allotments of competence by the various organisms.

  4. Mineral Status of Myocardial Sarcocystosis

    GA Kojouri


    Full Text Available Background: The role of minerals on parasite persistency and the interaction between minerals and animal responses to the parasite infestation is not clear. For these reasons, the present re­search was aimed to compare copper, zinc and iron status in sheep with parasitic myocarditis and healthy ones in 2009.Methods: Blood and heart tissue samples were collected from 145 slaughtered sheep and histopa­thological findings were confirmed as myocardial sarcocystosis in 27 cases. Serum and tis­sue mineral level were determined by atomic absorption spectroscopy. Data were analyzed by Sig­mastat program, using One Way Analysis of Variance (ANOVA at the level of P<0.05.Results: Myocardial sarcocystosis significantly increase myocardial concentration of Cu, Zn and Fe (P<0.05.Conclusion: These findings may explain the role of copper, zinc and iron in parasite persistency and may discuss the pathogenesis of sarcocystosis, which relates to evocate mentioned micronutri­ent to cardiac muscle.

  5. 25 CFR 215.25 - Other minerals and deep-lying lead and zinc minerals.


    ... 25 Indians 1 2010-04-01 2010-04-01 false Other minerals and deep-lying lead and zinc minerals. 215.25 Section 215.25 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING OPERATIONS AND LEASES, QUAPAW AGENCY § 215.25 Other minerals and deep-lying lead...

  6. Minerals yearbook: Mineral industries of Asia and the Pacific. Volume 3. 1991 international review



    This edition of the Minerals Yearbook records the performance of the worldwide minerals industry during 1991 and provides background information to assist in interpreting that performance. Content of the individual Yearbook volumes follows: Volume I, Metals and Minerals, contains chapters on virtually all metallic and industrial mineral commodities important to the U.S. economy. Volume II, Area Reports: Domestic, contains chapters on the minerals industry of each of the 50 States and Puerto Rico, Northern Marianas, Island Possessions, and Trust Territory. Volume III, Area Reports: International, contains the latest available mineral data on more than 160 foreign countries and discuss the importance of minerals to the economies of these nations.

  7. Mineral resource of the month: vermiculite

    Tanner, Arnold O.


    Vermiculite comprises a group of hydrated, laminar magnesium-aluminum-iron silicate minerals resembling mica. They are secondary minerals, typically altered biotite, iron-rich phlogopite or other micas or clay-like minerals that are themselves sometimes alteration products of amphibole, chlorite, olivine and pyroxene. Vermiculite deposits are associated with volcanic ultramafic rocks rich in magnesium silicate minerals, and flakes of the mineral range in color from black to shades of brown and yellow. The crystal structure of vermiculite contains water molecules, a property that is critical to its processing for common uses.

  8. Perencanaan Strategik SBU Mineral PT Sucofindo (Persero

    Suprapto Suprapto


    Full Text Available Strategic planning requires an organization in the face of today's business competition and a more complex future. Likewise, Mineral Gas Station also requires this strategic planning as a newly formed business unit of 2015. Therefore, the company analyzed its internal and external factors as well as a future review of the mineral service industry to stay afloat, grow and develop. The objectives of this study were to identify the internal performance and core competencies of Mineral Gas Station, to identify the external macro environment condition and external micro intensity of mineral service industry competition, to map the current position of the company, to recommend appropriate business strategy in facing competition pressure, and to develop the objectives and program of the company. This research used descriptive and quantitative analysis methods with a purposive sampling technique. The results show that the position of Mineral Gas Station on the intensity of mineral service competition is 'moderate' and is in quadrant of 'grow and build'. Therefore, the appropriate strategy is intensive strategy (market penetration, market development and product development. Mineral Gas Station require to conduct customer satisfaction surveys related to customer perspectives which becomes the most important strategic factor with a focus on customer complaint factor. Further research is needed by involving all external parties so that the results will be more independent.Keywords: mineral services, strategic planning, competition, mineral gas station, SucofindoABSTRAKPerencanaan strategik dibutuhkan organisasi dalam menghadapi persaingan bisnis saat ini dan masa depan yang semakin komplek. Demikian juga yang dibutuhkan SBU Mineral sebagai unit bisnis yang baru terbentuk 2015, dengan menganalisis faktor internal dan ekternal perusahaan serta tinjauan masa depan industri jasa mineral untuk tetap bertahan, tumbuh dan berkembang. Tujuan penelitian ini adalah

  9. Sorption of pesticides to aquifer minerals

    Clausen, Liselotte; Fabricius, Ida Lykke


    This paper summarizes results from a work were the sorption of five pesticides on seven minerals were studied in order to quantify the adsorption to different mineral surfaces. Investigated mineral phases are: quartz, calcite, kaolinite, a-alumina, and three iron oxides (2-line ferrihydrite, goet......, goethite, lepidocrocite). Selected pesticides are: atrazine, isoproturon, mecoprop, 2,4-D, and bentazone. The results demonstrate that pesticides adsorb to pure mineral surfaces. However, the size of the adsorption depends on the type of pesticide and the type of mineral....

  10. Sodium bicarbonated mineral water decreases postprandial lipaemia in postmenopausal women compared to a low mineral water

    S. Schoppen; Pérez Granados, Ana M.; Carbajal, A.; Sarriá, Beatriz; Sánchez-Muniz, F. J.; J. A. Gómez-Gerique; Vaquero, M. Pilar


    The role of bicarbonated mineral waters on lipid metabolism and lipoprotein concentrations in man has scarcely been investigated. The present study aimed to investigate whether drinking sodium bicarbonated mineral water affects postprandial cholesterol and triacylglycerol metabolism in postmenopausal women. In a three-way, randomised, crossover study, eighteen healthy postmenopausal women consumed two sodium bicarbonated mineral waters (bicarbonated mineral water 1 and bicarbonated mineral wa...

  11. Structure-mechanics relationships in mineralized tendons.

    Spiesz, Ewa M; Zysset, Philippe K


    In this paper, we review the hierarchical structure and the resulting elastic properties of mineralized tendons as obtained by various multiscale experimental and computational methods spanning from nano- to macroscale. The mechanical properties of mineralized collagen fibres are important to understand the mechanics of hard tissues constituted by complex arrangements of these fibres, like in human lamellar bone. The uniaxial mineralized collagen fibre array naturally occurring in avian tendons is a well studied model tissue for investigating various stages of tissue mineralization and the corresponding elastic properties. Some avian tendons mineralize with maturation, which results in a graded structure containing two zones of distinct morphology, circumferential and interstitial. These zones exhibit different amounts of mineral, collagen, pores and a different mineral distribution between collagen fibrillar and extrafibrillar space that lead to distinct elastic properties. Mineralized tendon cells have two phenotypes: elongated tenocytes placed between fibres in the circumferential zone and cuboidal cells with lower aspect ratios in the interstitial zone. Interestingly some regions of avian tendons seem to be predestined to mineralization, which is exhibited as specific collagen cross-linking patterns as well as distribution of minor tendon constituents (like proteoglycans) and loss of collagen crimp. Results of investigations in naturally mineralizing avian tendons may be useful in understanding the pathological mineralization occurring in some human tendons. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Quantitative Prediction for Deep Mineral Exploration

    Zhao Pengda; Cheng Qiuming; Xia Qinglin


    On reviewing the characteristics of deep mineral exploration, this article elaborates on the necessity of employing quantitative prediction to reduce uncertainty. This is caused by complexity of mineral deposit formational environments and mineralization systems as increase of exploration depth and incompleteness of geo-information from limited direct observation. The authors wish to share the idea of "seeking difference" principle in addition to the "similar analogy" principle in deep mineral exploration, especially the focus is on the new ores in depth either in an area with discovered shallow mineral deposits or in new areas where there are no sufficient mineral deposit models to be compared. An on-going research project, involving Sn and Cu mineral deposit quantitative prediction in the Gejiu (个旧) area of Yunnan (云南) Province, China, was briefly introduced to demonstrate how the "three-component" (geoanomaly-mineralization diversity-mineral deposit spectrum) theory and non-linear methods series in conjunction with advanced GIS technology, can be applied in multi-scale and multi-task deep mineral prospecting and quantitative mineral resource assessment.

  13. Mineralization of Carbon Dioxide: Literature Review

    Romanov, V; Soong, Y; Carney, C; Rush, G; Nielsen, B; O' Connor, W


    CCS research has been focused on CO2 storage in geologic formations, with many potential risks. An alternative to conventional geologic storage is carbon mineralization, where CO2 is reacted with metal cations to form carbonate minerals. Mineralization methods can be broadly divided into two categories: in situ and ex situ. In situ mineralization, or mineral trapping, is a component of underground geologic sequestration, in which a portion of the injected CO2 reacts with alkaline rock present in the target formation to form solid carbonate species. In ex situ mineralization, the carbonation reaction occurs above ground, within a separate reactor or industrial process. This literature review is meant to provide an update on the current status of research on CO2 mineralization. 2

  14. Decorin modulates matrix mineralization in vitro

    Mochida, Yoshiyuki; Duarte, Wagner R.; Tanzawa, Hideki; Paschalis, Eleftherios P.; Yamauchi, Mitsuo


    Decorin (DCN), a member of small leucine-rich proteoglycans, is known to modulate collagen fibrillogenesis. In order to investigate the potential roles of DCN in collagen matrix mineralization, several stable osteoblastic cell clones expressing higher (sense-DCN, S-DCN) and lower (antisense-DCN, As-DCN) levels of DCN were generated and the mineralized nodules formed by these clones were characterized. In comparison with control cells, the onset of mineralization by S-DCN clones was significantly delayed; whereas it was markedly accelerated and the number of mineralized nodules was significantly increased in As-DCN clones. The timing of mineralization was inversely correlated with the level of DCN synthesis. In these clones, the patterns of cell proliferation and differentiation appeared unaffected. These results suggest that DCN may act as an inhibitor of collagen matrix mineralization, thus modulating the timing of matrix mineralization.



    <正>20110144 Hu Lan(Anhui Institute of Geological Experiment,Hefei 230001,China);Liu Yueyou Determination of Micro-amount of Bismuth in Polymetallic Ores by Hydride Generation-Atomic Fluorescence Spectrometry with Alkaline Mode(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(1),2010,p.87-88,2 tables,10 refs.)Key words:atomic fluorescence spectrometry,bismuthA method for the determination of micro-amount of bismuth in polymetallic ores by hydride gen



    20150204 Abaydulla Alimjan(Department of Chemistry and Environmental Sciences,Kashgar Teachers College,Kashgar 844006,China);Cheng Chunying Non-Metallic Element Composition Analysis of Non-Ferrous Metal Ores from Oytagh Town,Xinjiang(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,33(1),2014,p.44-50,5illus.,4tables,28refs.)Key words:nonferrous metals ore,nonmetals,chemical analysis,thermogravimetric analysis Anions in non-ferrous ore materials

  17. Mineral Resource Information System for Field Lab in the Osage Mineral Reservation Estate

    Carroll, H.B.; Johnson, William I.


    The Osage Mineral Reservation Estate is located in Osage County, Oklahoma. Minerals on the Estate are owned by members of the Osage Tribe who are shareholders in the Estate. The Estate is administered by the Osage Agency, Branch of Minerals, operated by the U.S. Bureau of Indian Affairs (BIA). Oil, natural gas, casinghead gas, and other minerals (sand, gravel, limestone, and dolomite) are exploited by lessors. Operators may obtain from the Branch of Minerals and the Osage Mineral Estate Tribal Council leases to explore and exploit oil, gas, oil and gas, and other minerals on the Estate. Operators pay a royalty on all minerals exploited and sold from the Estate. A mineral Resource Information system was developed for this project to evaluate the remaining hydrocarbon resources located on the Estate. Databases on Microsoft Excel spreadsheets of operators, leases, and production were designed for use in conjunction with an evaluation spreadsheet for estimating the remaining hydrocarbons on the Estate.



    <正>20110887 Chen Yong(College of Geo-Resources and Information,China University of Petroleum,Qingdao 266555,China);Ge Yunjin Experimental Study on the Modes of Hydrocarbon-Bearing Inclusion Trapped in Carbonate Rock Reservoirs(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(3),2010,p.217-220,1 illus.,16 refs.,with English abstract)Key words:petroleum products,organic inclusion,carbonates20110888 Cheng Zhizhong(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China);Gu Tiexin Preparation of Nine Iron Ore Reference Materials of GFe-1~GFe-9(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,29(3),2010,p.305-308,5 tables,13 refs.)Key words:iron ores,type specimens Nine standard reference iron ore samples of GFe-1~GFe-9 were developed.The concentrations of TFe of the samples ranged from 20.17% to 66.87%,which covered a wide iron concentration range from concentrated iron ore powder to poor iron ores and can meet the needs for iron ore exploration and ore-dressing.Powder XRF technique was used for homogeneity test and the analytical results indicated that all elements tested were in good homogeneity.

  19. Mineral fibre persistence and carcinogenicity.

    McDonald, J C


    Epidemiological research during the past 40 years has demonstrated with increasing clarity that amphibole asbestos fibres--crocidolite, amosite and tremolite--are more carcinogenic than chrysotile. A smaller number of well-controlled studies using lung burden analyses, while adding to the specificity of this conclusion, have shown that amphibole fibres also differ from chrysotile in being far more durable and biopersistent in lung tissue. Analyses of mesothelioma and lung cancer in a large cohort of Canadian chrysotile miners and millers have recently shown that the low-level presence of fibrous tremolite in these mines, rather than the chrysotile, may well be responsible. The high risk of lung cancer, but not of mesothelioma, in the chrysotile textile industry remains anomalous and cannot be explained in this way. These various findings are directly relevant to the choice of the experimental methods which should be used for screening man-made fibres for industrial use. Although it is clear that biopersistence is a major determinant of cancer risk in animals, and perhaps also in man, other factors affecting the biological activity of mineral fibres may also be important.

  20. Improving power conversion efficiency of perovskite solar cells by cooperative LSPR of gold-silver dual nanoparticles

    Liu, Peng; Yang, Bing-chu; Liu, Gang; Wu, Run-Sheng; Zhang, Chu-jun; Wan, Fang; Li, Shui-gen; Yang, Jun-liang; Gao, Yong-li; Zhou, Cong-hua


    Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 61306080, 51203192, 11334014, and 51664047), the Natural Science Foundation of Hunan Province, China (Grant No. 2015JJ3143), and the Scientific and Technological Project of Hunan Provincial Development and Reform Commission, China.

  1. Gold & silver nanoparticles supported on manganese oxide: Synthesis, characterization and catalytic studies for selective oxidation of benzyl alcohol

    Saad Alabbad


    Full Text Available Nano-gold and silver particles supported on manganese oxide were synthesized by the co-precipitation method. The catalytic properties of these materials were investigated for the oxidation of benzyl alcohol using molecular oxygen as a source of oxygen. The catalyst was calcined at 300, 400 and 500 °C. They were characterized by electron microscopy, powder X-ray diffraction (XRD and surface area. It was observed that the calcination temperature affects the size of the nanoparticle, which plays a significant role in the catalytic process. The catalyst calcined at 400 °C, gave a 100% conversion and >99% selectivity, whereas catalysts calcined at 300 and 500 °C gave a conversion of 69.51% and 19.90% respectively, although the selectivity remains >99%.

  2. Autotrophic biofilm development on superficial samples of the gold-silver mine tailings, Valenciana (Mexico): pioneers in tailings remediation?

    García-Meza, Jessica Viridiana


    We report the results of long term bio-assays on microorganism colonization of mine tailings samples, taken from the Valenciana mine tailings (Guanajuato, Mexico), under stable laboratory conditions (humidity, temperature, light exposure). In order to identify the main metabolic groups of the potentially colonizing microorganisms and the implications of their growth on the main tailing's characteristics related to biological succession, organic matter (OM) content, cationic exchange capacity (CEC), and pH values were measured as the colonization took place. We observe that photosynthetic biofilms (cyanobacteria, green algae, and diatoms) successfully colonize the mine tailings samples as pioneers; moreover, bacteria, yeast and fungi were also identified. Biofilm colonization significantly improved the OM contents, whereas the pH value is not modified during the entire observed colonization process. The results suggest that biofilms are useful during the first steps of the mine tailings remediation. This is the first report of microalgae and cyanobacteria grown of on tailings samples obtained from a semiarid region.

  3. Mechanism of pH-switchable peroxidase and catalase-like activities of gold, silver, platinum and palladium.

    Li, Junnan; Liu, Wenqi; Wu, Xiaochun; Gao, Xingfa


    Despite being increasingly used as artificial enzymes, little has been known for the origin of the pH-switchable peroxidase-like and catalase-like activities of metals. Using calculations and experiments, we report the mechanisms for both activities and their pH-switchability for metals Au, Ag, Pd and Pt. The calculations suggest that both activities are intrinsic properties of metals, regardless of the surfaces and intersections of facets exposed to environments. The pre-adsorbed OH groups on the surfaces, which are only favorably formed in basic conditions, trigger the switch between both activities and render the pH-switchability. The adsorption energies between H2O2 and metals can be used as convenient descriptors to predict the relative enzyme-like activities of the metals with similar surface morphologies. The results agree with the enzyme-mimic activities that have been experimentally reported for Au, Ag, Pt and predict that Pd should have the similar properties. The prediction, as well as the predicted activity order for the four metals, has been verified by the experimental tests. The results thus provide an in-depth insight into the peroxidase-like and catalase-like activities of the metals and will guide the de novo design, synthesis and application of artificial enzymes based on inorganic materials.

  4. Extremely sensitive sandwich assay of kanamycin using surface-enhanced Raman scattering of 2-mercaptobenzothiazole labeled gold@silver nanoparticles.

    Zengin, Adem; Tamer, Ugur; Caykara, Tuncer


    Herein, we report the development of extremely sensitive sandwich assay of kanamycin using a combination of anti-kanamycin functionalized hybrid magnetic (Fe3O4) nanoparticles (MNPs) and 2-mercaptobenzothiazole labeled Au-core@Ag-shell nanoparticles as the recognition and surface-enhanced Raman scattering (SERS) substrate, respectively. The hybrid MNPs were first prepared via surface-mediated RAFT polymerization of N-acryloyl-L-glutamic acid in the presence of 2-(butylsulfanylcarbonylthiolsulfanyl) propionic acid-modified MNPs as a RAFT agent and then biofunctionalized with anti-kanamycin, which are both specific for kanamycin and can be collected via a simple magnet. After separating kanamycin from the sample matrix, they were sandwiched with the SERS substrate. According to our experimental results, the limit of detection (LOD) was determined to be 2pg mL(-1), this value being about 3-7 times more than sensitive than the LOD of previously reported results, which can be explained by the higher SERS activity of silver coated gold nanoparticles. The analysis time took less than 10min, including washing and optical detection steps. Furthermore, the sandwich assay was evaluated for investigating the kanamycin specificity on neomycin, gentamycin and streptomycin and detecting kanamycin in artificially contaminated milk.

  5. Electrum, the Gold-Silver Alloy, from the Bulk Scale to the Nanoscale: Synthesis, Properties, and Segregation Rules.

    Guisbiers, Grégory; Mendoza-Cruz, Rubén; Bazán-Díaz, Lourdes; Velázquez-Salazar, J Jesús; Mendoza-Perez, Rafael; Robledo-Torres, José Antonio; Rodriguez-Lopez, José-Luis; Montejano-Carrizales, Juan Martín; Whetten, Robert L; José-Yacamán, Miguel


    The alloy Au-Ag system is an important noble bimetallic phase, both historically (as "Electrum") and now especially in nanotechnology, as it is applied in catalysis and nanomedicine. To comprehend the structural characteristics and the thermodynamic stability of this alloy, a knowledge of its phase diagram is required that considers explicitly its size and shape (morphology) dependence. However, as the experimental determination remains quite challenging at the nanoscale, theoretical guidance can provide significant advantages. Using a regular solution model within a nanothermodynamic approach to evaluate the size effect on all the parameters (melting temperature, melting enthalpy, and interaction parameters in both phases), the nanophase diagram is predicted. Besides an overall shift downward, there is a "tilting" effect on the solidus-liquidus curves for some particular shapes exposing the (100) and (110) facets (cube, rhombic dodecahedron, and cuboctahedron). The segregation calculation reveals the preferential presence of silver at the surface for all the polyhedral shapes considered, in excellent agreement with the latest transmission electron microscopy observations and energy dispersive spectroscopy analysis. By reviewing the nature of the surface segregated element of different bimetallic nanoalloys, two surface segregation rules, based on the melting temperatures and surface energies, are deduced. Finally, the optical properties of Au-Ag nanoparticles, calculated within the discrete dipole approximation, show the control that can be achieved in the tuning of the local surface plasmon resonance, depending of the alloy content, the chemical ordering, the morphology, the size of the nanoparticle, and the nature of the surrounding environment.

  6. Synthesis of Hollow Gold-Silver Alloyed Nanoparticles: A "Galvanic Replacement" Experiment for Chemistry and Engineering Students

    Jenkins, Samir V.; Gohman, Taylor D.; Miller, Emily K.; Chen, Jingyi


    The rapid academic and industrial development of nanotechnology has led to its implementation in laboratory teaching for undergraduate-level chemistry and engineering students. This laboratory experiment introduces the galvanic replacement reaction for synthesis of hollow metal nanoparticles and investigates the optical properties of these…

  7. First-principles study of the contractive reconstruction of gold and silver monolayers on gold, silver and aluminum

    Takeuchi, Noboru.


    Using first-principles calculations in conjunction with modeling techniques, the author has investigated the structures of Au and Ag monolayers on a number of metal surfaces. Au(100) has a c(26 {times} 68) surface unit cell and the reconstruction has been interpreted as the top layer transforming to a contracted hexagonal-close-packed layer, superimposed on the square lattice of the underlying substrate atoms. Similar reconstructions have been observed on the 5d fcc metals Ir and Pt, but not in the 4d Rh, Pd, and Ag. The author studied the energetics of a monolayer of Au and Ag using first-principles calculations. The author found that it is energetically favorable for both Au and Ag to transform from a square to hexagonal arrangement and to contract to a higher surface density, but Au gains substantially more energy than Ag. This is true both for a monolayer in isolation as well as on top of a jellium surface. The author also calculated the mismatch energy (energy loss when the top layer loses registry with the substrate) for Au and Ag, and found that Ag has a slightly higher mismatch energy. The first-principles results thus offer a strong indication that Au(100) can reconstruct but Ag will not. The reconstruction is further studied with a 2 dimensional Frenkel-Kontorowa model, with parameters extracted from the total energy calculations. The author found that it is indeed energetically favorable for the top layer of Au(100), but not for Ag, to transform to a hexagonal-close-packed structure and contract. 85 refs., 34 figs., 8 tabs.

  8. No evidence of the genotoxic potential of gold, silver, zinc oxide and titanium dioxide nanoparticles in the SOS chromotest.

    Nam, Sun-Hwa; Kim, Shin Woong; An, Youn-Joo


    Gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are widely used in cosmetic products such as preservatives, colorants and sunscreens. This study investigated the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest with Escherichia coli PQ37. The maximum exposure concentrations for each nanoparticle were 3.23 mg l(-1) for Au NPs, 32.3 mg l(-1) for Ag NPs and 100 mg l(-1) for ZnO NPs and TiO2 NPs. Additionally, in order to compare the genotoxicity of nanoparticles and corresponding dissolved ions, the ions were assessed in the same way as nanoparticles. The genotoxicity of the titanium ion was not assessed because of the extremely low solubility of TiO2 NPs. Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn, in a range of tested concentrations, exerted no effects in the SOS chromotest, evidenced by maximum IF (IFmax) values of below 1.5 for all chemicals. Owing to the results, nanosized Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn are classified as non-genotoxic on the basis of the SOS chromotest used in this study. To the best of our knowledge, this is the first study to evaluate the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest.

  9. Synthesis of Hollow Gold-Silver Alloyed Nanoparticles: A "Galvanic Replacement" Experiment for Chemistry and Engineering Students

    Jenkins, Samir V.; Gohman, Taylor D.; Miller, Emily K.; Chen, Jingyi


    The rapid academic and industrial development of nanotechnology has led to its implementation in laboratory teaching for undergraduate-level chemistry and engineering students. This laboratory experiment introduces the galvanic replacement reaction for synthesis of hollow metal nanoparticles and investigates the optical properties of these…

  10. Influence of gold, silver and gold–silver alloy nanoparticles on germ cell function and embryo development

    Ulrike Taylor


    Full Text Available The use of engineered nanoparticles has risen exponentially over the last decade. Applications are manifold and include utilisation in industrial goods as well as medical and consumer products. Gold and silver nanoparticles play an important role in the current increase of nanoparticle usage. However, our understanding concerning possible side effects of this increased exposure to particles, which are frequently in the same size regime as medium sized biomolecules and accessorily possess highly active surfaces, is still incomplete. That particularly applies to reproductive aspects, were defects can be passed onto following generations. This review gives a brief overview of the most recent findings concerning reprotoxicological effects. The here presented data elucidate how composition, size and surface modification of nanoparticles influence viablility and functionality of reproduction relevant cells derived from various animal models. While in vitro cultured embryos displayed no toxic effects after the microinjection of gold and silver nanoparticles, sperm fertility parameters deteriorated after co-incubation with ligand free gold nanoparticles. However, the effect could be alleviated by bio-coating the nanoparticles, which even applies to silver and silver-rich alloy nanoparticles. The most sensitive test system appeared to be in vitro oocyte maturation showing a dose-dependent response towards protein (BSA coated gold–silver alloy and silver nanoparticles leading up to complete arrest of maturation. Recent biodistribution studies confirmed that nanoparticles gain access to the ovaries and also penetrate the blood–testis and placental barrier. Thus, the design of nanoparticles with increased biosafety is highly relevant for biomedical applications.

  11. Environmental Influences on Elite Sport Athletes Well Being: From Gold, Silver, and Bronze to Blue Green and Gold

    Donnelly, Aoife A.; MacIntyre, Tadhg E.; O’Sullivan, Nollaig; Warrington, Giles; Harrison, Andrew J.; Igou, Eric R.; Jones, Marc; Gidlow, Chris; Brick, Noel; Lahart, Ian; Cloak, Ross; Lane, Andrew M.


    This paper considers the environmental impact on well-being and performance in elite athletes during Olympic competition. The benefits of exercising in natural environments are recognized, but less is known about the effects on performance and health in elite athletes. Although some Olympic events take place in natural environments, the majority occur in the host city, usually a large densely populated area where low exposure to natural environments is compounded by exposure to high levels of air, water, and noise pollution in the ambient environment. By combining methods and expertise from diverse but inter-related disciplines including environmental psychology, exercise physiology, biomechanics, environmental science, and epidemiology, a transdisciplinary approach will facilitate a greater understanding of the effects of the environment on Olympic athletes. PMID:27540370

  12. Quantifying the Impact of Nanoparticle Coatings and Non-uniformities on XPS Analysis: Gold/silver Core-shell Nanoparticles

    Wang, Yung-Chen Andrew; Engelhard, Mark H.; Baer, Donald R.; Castner, David G.


    Abstract or short description: Spectral modeling of photoelectrons can serve as a valuable tool when combined with X-ray photoelectron spectroscopy (XPS) analysis. Herein, a new version of the NIST Simulation of Electron Spectra for Surface Analysis (SESSA 2.0) software, capable of directly simulating spherical multilayer NPs, was applied to model citrate stabilized Au/Ag-core/shell nanoparticles (NPs). The NPs were characterized using XPS and scanning transmission electron microscopy (STEM) to determine the composition and morphology of the NPs. The Au/Ag-core/shell NPs were observed to be polydispersed in size, non-circular, and contain off-centered Au-cores. Using the average NP dimensions determined from STEM analysis, SESSA spectral modeling indicated that washed Au/Ag-core shell NPs were stabilized with a 0.8 nm l

  13. Environmental influences on Elite Sport Athletes Well Being: From Gold, Silver and Bronze to Blue Green and Gold

    Aoife A. Donnelly


    Full Text Available This paper considers the environmental impact on well-being and performance in elite athletes during Olympic competition. The benefits of exercising in natural environments are recognised, but less is known about the effects on performance and health in elite athletes. Although some Olympic events take place in natural environments, the majority occur in the host city, usually a large densely populated area where low exposure to natural environments is compounded by exposure to high levels of air, water and noise pollution in the ambient environment. By combining methods and expertise from diverse but inter-related disciplines including environmental psychology, exercise physiology, biomechanics, environmental science and epidemiology, a transdisciplinary approach will facilitate a greater understanding of the effects of the environment on Olympic athletes.

  14. Nanofiltration renovation of mineral water

    Bodzek Michał


    Full Text Available There is often a need to improve the taste of mineral water by reducing the sulphate ion content. It was found that for such an effect, nanofiltration (NF process can be used. In the case, the proposed formula was assumed obtaining a mineral water with reduction of H2S and SO42- content through the following processes: stripping - UF/MF or rapid fi ltration - nanofiltration - mixing with raw water or filtration through calcium bed. The paper shows the results of the tests, with use of mineral waters and nanofiltration. Commercial nanofiltration membranes NF-270 Dow Filmtec and NF-DK GE Infrastructure Water&Process Technologies were applied. NF was carried out for mixed water from both water intakes (1 and 2, recovery of 50%, at transmembrane pressure of 0.8-1.2 MPa in the dead-end fi ltration mode. In addition, the permeate obtained in NF was filtered through a column fi lled with 1.0-3.0 mm limestone rock, in order to improve the composition of mineral water. The tested mineral water is the sulphate-chloride-sodium-calcium-magnesium in nature and contains 991 mg/L of SO42- and 2398 mg/L of TDS, while the permeate after NF showed the chloride - sodium hydrogeochemical type (TDS: 780-1470 mg/L, sulfate 10-202.7 mg/L, calcium 23-39.7 mg/L, magnesium 11-28 mg/L. As a result of water treatment in the NF process, high reduction of SO42- ions was obtained (79-98.7%, while the TDS was reduced in 51-64%. Because the process of NF allows for relatively high reduction of bivalent ions, a significant reduction in calcium ion content (84-88% and magnesium (84-89% has been also obtained. Monovalent ions were reduced to a lesser extent, i.e. sodium in 46% and bicarbonates in 39-64.1%. Despite obtaining the positive effect of the sulphate ions content reduction, the NF process significantly changed the mineralogy composition of water. The permeate filtration (DK-NF membrane on the CaCO3 deposit led to a correction of the hydrogeochemical type of water from

  15. Mineral physics and mineral chemistry at the Australian National University

    Jackson, Ian

    Research at the Australian National University (ANU) in Canberra into the physics and chemistry of minerals is being actively carried out by a number of different research groups within the Research School of Earth Sciences (RSES), the Research School of Chemistry (RSC), and the Department of Geology. The research schools form part of the Institute of Advanced Studies, which is a national center for research and postgraduate training established by the Australian Government in 1946. The Institute of Advanced Studies seeks to ensure flexibility in its approach to research by maintaining an unusually high ratio (>1) of nontenured to tenured staff. Two types of nontenured appointment are available: postdoctoral fellowships of 1-2 yr duration and research fellowships tenable for 3-5 yr. The Department of Geology, as part of the Faculty of Science, is responsible for the provision of undergraduate education in geology, in addition to its role in research and postgraduate training.

  16. The nanosphere iron mineral(s) in Mars soil

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.


    A series of surface-modified clays containing nanophase (np) iron/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these 'Mars-soil analogs' were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxyl mineral such as 'green rust', or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable meaghemite (gamma-Fe203) by mild heat treatment and then to nanophase hematite (aplha-Fe203) by extensive heat treatment. Their chemical reactivity offers a plausible mechanism for the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxide and silicate phase surfaces. The mode of formation of these (nanophase) iron oxides on Mars is still unknown.

  17. Defective skeletal mineralization in pediatric CKD.

    Wesseling-Perry, Katherine


    Although traditional diagnosis and treatment of renal osteodystrophy focused on changes in bone turnover, current data demonstrate that abnormalities in skeletal mineralization are also prevalent in pediatric chronic kidney disease (CKD) and likely contribute to skeletal morbidities that continue to plague this population. It is now clear that alterations in osteocyte biology, manifested by changes in osteocytic protein expression, occur in early CKD before abnormalities in traditional measures of mineral metabolism are apparent and may contribute to defective skeletal mineralization. Current treatment paradigms advocate the use of 1,25(OH)2vitamin D for the control of secondary hyperparathyroidism; however, these agents fail to correct defective skeletal mineralization and may exacerbate already altered osteocyte biology. Further studies are critically needed to identify the initial trigger for abnormalities of skeletal mineralization as well as the potential effects that current therapeutic options may have on osteocyte biology and bone mineralization.

  18. Mining and minerals policy: 1976 bicentennial edition


    The report is organized into three basic parts. The first part, the Executive Summary, provides a brief description of the major topics and lists the issues and recommendations. The report then is divided into two sections. Section I, Summary, is comprised of three chapters: Increased Energy Security; Metals and Nonmetallic Minerals; and Trends and Events. Section II, Issues in Energy and Minerals Policy, is comprised of seven chapters: Federal Leasing; The Federal Role in Reducing the Fiscal Impacts of Energy Development; Availability of Federal Lands for Mineral Exploration and Development; Environmental Issues and the Mineral Industry; Developments in International Minerals Trade and Investment; Ocean Mining; and The Development of New Tools for Energy and Minerals Policy Analysis. (MCW)

  19. Regulation of bone mineral loss during lactation

    Brommage, R.; Deluca, H. F.


    The effects of varyng dietary calcium and phosphorous levels, vitamin D deficiency, oophorectomy, adrenalectomy, and simultaneous pregnancy on bone mineral loss during lactation in rats are studied. The experimental procedures and evaluations are described. The femur ash weight of lactating and nonlactating rats are calculated. The data reveals that a decrease in dietary calcium of 0.02 percent results in an increased loss of bone mineral, an increase in calcium to 1.4 percent does not lessen bone mineral loss, and bone mineral loss in vitamin D deficient rats is independent of calcium levels. It is observed that changes in dietary phosphorous level, oophorectomy, adrenalectomy, and simultaneous pragnancy do not reduce bone mineral loss during lactation. The analysis of various hormones to determine the mechanism that triggers bone mineral loss during lactation is presented.

  20. Calculation of topological connectivity index for minerals


    Topological method was applied firstly to calculate the topological connectivity index of minerals (TCIM). The reciprocal of effective atomic refractivity of metal dement in minerals was chosen as its valence. The reasonability of TCIM as an activity criterion was tested through comparison of TCIM with two kinds of dectronegativity parameter, i.e. ionic percentage and energy criteria of Yang's electronegativity, solubility product, energy criterion according to the gen eralized perturbation theory and adsorption of flotation reagents on the surface of minerals. The results indicated that TCIM is an effective structural parameter of minerals to study the structure-activity relationship. In addition, different mineral is of different TCIM value, so TCIM brings about convenience in comparison of flotation activity for minerals.

  1. Determination of silver, gold, zinc and copper in mineral samples by various techniques of instrumental neutron activation analysis; Determinacion de plata, oro, zinc y cobre en muestras minerales mediante diversas tecnicas de analisis por activacion de neutrones instrumental

    Rodriguez R, N. I.; Rios M, C.; Pinedo V, J. L. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Yoho, M.; Landsberger, S., E-mail: [University of Texas at Austin, Nuclear Engineering Teaching Laboratory, Austin 78712, Texas (United States)


    Using the method of instrumental neutron activation analysis, mineral exploration samples were analyzed in order to determine the concentrations of silver, gold, zinc and copper; these minerals being the main products of benefit of Tizapa and Cozamin mines. Samples were subjected to various techniques, where the type of radiation and counting methods were chosen based on the specific isotopic characteristics of each element. For calibration and determination of concentrations the comparator method was used, certified standards were subjected to the same conditions of irradiation and measurement that the prospecting samples. The irradiations were performed at the research reactor TRIGA Mark II of the University of Texas at Austin. The silver concentrations were determined by Cyclical Epithermal Neutron Activation Analysis. This method in combination with the transfer pneumatic system allowed a good analytical precision and accuracy in prospecting for silver, from photo peak measurement 657.7 keV of short half-life radionuclide {sup 110}Ag. For the determination of gold and zinc, Epithermal Neutron Activation Analysis was used, the photo peaks analyzed corresponded to the energies 411.8 keV of radionuclide {sup 199}Au and 438.6 keV of metastable radionuclide {sup 69m}Zn. On the other hand, copper quantification was based on the photo peak analysis of 1039.2 keV produced by the short half-life radionuclide {sup 66}Cu, by Thermal Neutron Activation Analysis. The photo peaks measurement corresponding to gold, zinc and copper was performed using a Compton suppression system, which allowed an improvement in the signal to noise relationship, so that better detection limits and low uncertainties associated with the results were obtained. Comparing elemental concentrations the highest values in silver, zinc and copper was for samples of mine Tizapa. Regarding gold values were found in the same range for both mines. To evaluate the precision and accuracy of the methods used

  2. Polypeptide Inhibitors of Mineral Scaling and Corrosion


    peptides are based on natural protein inhibitors of mineral formation and generally are enriched in aspartic acid and phosphoserine. Specifically, the...the protein inhibitors of mineral formation , we evaluated several methods of preparation of phosphopeptides. These included direct polymerization of 2...number of assays have been developed to measure the ability of the peptides to inhibit mineral formation . These include methods for assessing effects on

  3. Role of minerals in animal health disorders

    Sinovec Zlatan J.


    Full Text Available All mineral matter, essential or non-essential, can have a significant influence on production results and the health of animals, if large quantities of them are present in a feed ration. A maximally tolerant content depends on the animal specie and category. Many factors, such as physiological status (growth, lactation, etc., nutritive status, content and ratio of nutritive matter in the ration, duration of exposure, and the biological level of utilization of elements, also affect the maximally tolerant content of mineral matter in feed. The content of certain mineral matter in plant feed significantly depends on the soil factor, as well as the content and level of utilization of mineral matter from the soil. Mn, Se and Mo can be present in plant feed in such quantities as to induce toxicosis. Industrial contaminants, Cd, Pb or F, can contaminate plants, in particular their leaves, in quantities which lead to the appearance of clinical signs of conventional toxicosis. Moreover, natural water can contain large quantities of S, F, Na, Mg, or Fe, and certain mineral matter can get into water through industrial waste. In addition to the above, it is possible to cause unwanted effects through the frequent, but primarily unprofessional use of mineral additives, since it is extremely important, besides meeting the mineral requirements of each individual element, to secure a ratio among the mineral matter themselves as well as with other nutritive matter. Mineral matter present in food are in mutual interference, and these relations can be synergistic or antagonistic. The sufficiency of a large number of mineral matter has a negative effect on the utilization of other matter (conditional and/or border deficiency, while certain elements cause the clinical appearance of toxic effects. The accidental intake of large quantities of certain mineral matter is revealed as clinical signs of acute toxicosis, which is very different from chronic effects caused by

  4. Strategic Minerals: U.S. Alternatives


    become one of the world’s leading industrial powers by being a mineral-short nation. It has economic reserves in all but 12 of the 71 minerals in world...Sirategic Minerals and ferroalloy industries, the chemical and petrochemical indus- tries, the machine tool industry, and the nuclear power The historical record shows a mixed picture of reliability. Since World War II. supply problems have pestered metals users. Interruptions

  5. Mineral distributions at the developing tendon enthesis.

    Andrea G Schwartz

    Full Text Available Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM. A zone (∼20 µm exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked

  6. Mineral resource of the month: Mica

    Willett, Jason C.


    The mica mineral group includes 34 phyllosilicate minerals, all with a layered, platy texture. The mineral has been known for millennia: Mica was first mined in India about 4,000 years ago, where it was used primarily in medicines. The Mayans used it for decorative effect in stucco to make their temples sparkle in the sun. Today it is used in everything from electrical products to makeup.

  7. MINER: software for phylogenetic motif identification

    La, David; Livesay, Dennis R.


    MINER is web-based software for phylogenetic motif (PM) identification. PMs are sequence regions (fragments) that conserve the overall familial phylogeny. PMs have been shown to correspond to a wide variety of catalytic regions, substrate-binding sites and protein interfaces, making them ideal functional site predictions. The MINER output provides an intuitive interface for interactive PM sequence analysis and structural visualization. The web implementation of MINER is freely available at . ...

  8. Mineral distributions at the developing tendon enthesis.

    Schwartz, Andrea G; Pasteris, Jill D; Genin, Guy M; Daulton, Tyrone L; Thomopoulos, Stavros


    Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM). A zone (∼20 µm) exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked to endochondral

  9. Genetic Types of Diamond Mineralization

    A.A.MARAKUSHEV; 桑隆康; 等


    The paper describes the proposed models of diamond formation both in meteorites and in kimberlite and lamproite bodies.metamorphic complexes and explosive-ring structures ("astroblemes"),The diamond distribution in meteorites(chondrites,iron meteorites and ureilites)is restricted to taente-kamasite phase.The diamond generation here is tied up with the first stage of evolution of the planets,This stage is characterized by high pressure of hydrogen. leading to the formation of the planet envelope,The second stage of planet evolution began with the progressive imopoverishment of their atmospheres in hydrogen due to its predominant emission into the space and to progressive development of oxidative conditions.The model appears to have proved the relict nature of diamond mineraolization in meteorites.Diamond and other high-pressure minerals(its"satellites") were crystallized without any exception in the early intratelluric stages of peridotite and eclogite-pyroxenite magma evolution just before the magma intrusion into the higher levels of the mantle and crust where diamond is not thermodynamically stable,The ultramafic intrusive bodies(bearing rich relict diamonds)in the dase of a platform paaear to be the substrata for the formation of kimberlite-lamproite magma chambers as a result of magmatic replacement.The model explains the polyfacial nature of diamondiferous eclotgites,pyroxenites and peridotites and discusses the process of inheritance of their diamond mineralization by kimberlites and lamproites.Dimond oproductivity of metamorthic complexes is originated by the inheritance of their diamonds from the above-mentioned primary diamondiferous rocks.Large diamondiferous explosive-ring structures were formed by high-energy endogenic explosion of fluid which came from the Earth's core.This high energy differs endogenic impactogenesis from explosive volcanism.It proceeds at very high temperature to create diaplectic galsses(monomineral pseudomorphs)-the product of

  10. TUCS/phosphate mineralization of actinides

    Nash, K.L. [Argonne National Lab., IL (United States)


    This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

  11. Mineral elements in milk and dairy products

    Šimun Zamberlin


    Full Text Available Mineral elements occur in milk and dairy products as inorganic ions and salts, as well as part of organic molecules, such as proteins, fats, carbohydrates and nucleic acids. The chemical form of mineral elements is important because it determines their absorption in the intestine and their biological utilization. The mineral composition of milk is not constant because it depends on lactation phase, nutritional status of the animal, and environmental and genetic factors. The objective of this research is to point out the research results of chemical form, content and nutritional importance of individual mineral elements that are present in various milks and dairy products.

  12. Dietary Supplements and Sports Performance: Minerals

    Williams Melvin H


    Full Text Available Abstract Minerals are essential for a wide variety of metabolic and physiologic processes in the human body. Some of the physiologic roles of minerals important to athletes are their involvement in: muscle contraction, normal hearth rhythm, nerve impulse conduction, oxygen transport, oxidative phosphorylation, enzyme activation, immune functions, antioxidant activity, bone health, and acid-base balance of the blood. The two major classes of minerals are the macrominerals and the trace elements. The scope of this article will focus on the ergogenic theory and the efficacy of such mineral supplementation.

  13. Watering down the impact of mineral operations

    Huxley, C.


    New guidance for mineral operators and mineral planning authorities (MPAs) has been published by environmental consultants Symonds Travers Morgan on behalf of the Department of the Environment, Transport and the Regions (DETR) in a report called Reducing the effects of surface mineral workings on the water environment: a guide to good practice? The article explains its significance to mineral operators. The report highlights problems caused by opencast coal extraction, large-scale quarrying of limestone and chalk from major Karstic aquifers and sand and gravel workings in river flood planes. 1 ref., 6 photos.

  14. MINER: software for phylogenetic motif identification.

    La, David; Livesay, Dennis R


    MINER is web-based software for phylogenetic motif (PM) identification. PMs are sequence regions (fragments) that conserve the overall familial phylogeny. PMs have been shown to correspond to a wide variety of catalytic regions, substrate-binding sites and protein interfaces, making them ideal functional site predictions. The MINER output provides an intuitive interface for interactive PM sequence analysis and structural visualization. The web implementation of MINER is freely available at Source code is available to the academic community on request.

  15. Multiphase Sequestration Geochemistry: Model for Mineral Carbonation

    White, Mark D.; McGrail, B. Peter; Schaef, Herbert T.; Hu, Jian Z.; Hoyt, David W.; Felmy, Andrew R.; Rosso, Kevin M.; Wurstner, Signe K.


    Carbonation of formation minerals converts low viscosity supercritical CO2 injected into deep saline reservoirs for geologic sequestration into an immobile form. Until recently the scientific focus of mineralization reactions with reservoir rocks has been those that follow an aqueous-mediated dissolution/precipitation mechanism, driven by the sharp reduction in pH that occurs with CO2 partitioning into the aqueous phase. For sedimentary basin formations the kinetics of aqueous-mediated dissolution/precipitation reactions are sufficiently slow to make the role of mineralization trapping insignificant over a century period. For basaltic saline formations aqueous-phase mineralization progresses at a substantially higher rate, making the role of mineralization trapping significant, if not dominant, over a century period. The overlooked mineralization reactions for both sedimentary and basaltic saline formations, however, are those that occur in liquid or supercritical CO2 phase; where, dissolved water appears to play a catalyst role in the formation of carbonate minerals. A model is proposed in this paper that describes mineral carbonation over sequestration reservoir conditions ranging from dissolved CO2 in aqueous brine to dissolved water in supercritical CO2. The model theory is based on a review of recent experiments directed at understanding the role of water in mineral carbonation reactions of interest in geologic sequestration systems occurring under low water contents.

  16. Mineral Facilities of Latin America and Canada

    Bernstein, Rachel; Eros, Mike; Quintana-Velazquez, Meliany


    This data set consists of records for over 900 mineral facilities in Latin America and Canada. The mineral facilities include mines, plants, smelters, or refineries of aluminum, cement, coal, copper, diamond, gold, iron and steel, nickel, platinum-group metals, salt, and silver, among others. Records include attributes such as commodity, country, location, company name, facility type and capacity if applicable, and generalized coordinates. The data were compiled from multiple sources, including the 2003 and 2004 USGS Minerals Yearbooks (Latin America and Candada volume), data to be published in the 2005 Minerals Yearbook Latin America and Canada Volume, minerals statistics and information from the USGS minerals information Web site (, and data collected by USGS minerals information country specialists. Data reflect the most recent published table of industry structure for each country. Other sources include statistical publications of individual countries, annual reports and press releases of operating companies,and trade journals. Due to the sensitivity of some energy commodity data, the quality of these data should be evaluated on a country-by-country basis. Additional information and explanation is available from the country specialists.



    <正>20091570 Ge Yunjin(College of Geo-Resource and Information,China University of Petroleum,Dongying 257061,China);Chen Yong Advance in Low Temperature Phase Transition and Raman Spectrum Technique in Composition Determination of Fluid Inclusions(Rock and Mineral Analysis,ISSN0254-5357,CN11-2131/TD,27(3),2008,p.207-210,22 refs.)Key words:fluid inclusions,Raman spectraThe principle and development of low-temperature analytical techniques for fluid inclusions were expounded.The traditional low-temperature analytical technology mainly focused on the measurement of inorganic salt using congealed microthermometry,but now it is developed to semi-quantitative and quantitative analysis of fluid inclusions using in-situ cryogenic Raman spectrometry.

  18. Leptin and bone mineral density

    Morberg, Cathrine M.; Tetens, Inge; Black, Eva


    Leptin has been suggested to decrease bone mineral density (BMD). This observational analysis explored the relationship between serum leptin and BMD in 327 nonobese men (controls) (body mass index 26.1 +/- 3.7 kg/m(2), age 49.9 +/- 6.0 yr) and 285 juvenile obese men (body mass index 35.9 +/- 5.9 kg....../m(2), age 47.5 +/- 5.1 yr). Whole-body dual-energy x-ray absorptiometry scan measured BMD, fat mass, and lean mass. Fasting serum leptin (nanograms per milliliter) was strongly associated with fat mass (kilograms) in both controls (r = 0.876; P ....001). An inverse relation between BMD adjusted for body weight and serum leptin emerged in both the control group (r = -0.186; P

  19. Reducing the extraction of minerals

    Bouzon, Marina; Govindan, Kannan; Rodriguez, Carlos Manuel Taboada


    the Multi-Criteria Decision Making (MCDM) tool named Interpretive Structural Modeling (ISM) to evaluate the relationship between the barrier categories. Logistics experts from machinery manufacturing industry sector in Brazil were consulted. The greater influence on all barrier categories is Policy related......Mass consumption and shortening product lifecycles have increased worldwide production. Consequently, more raw materials such as minerals are used, and available landfills are filling up. Companies are urged to effectively incorporate sustainability issues such as End-of-life (EOL) management...... and Reverse Logistics (RL) practices to close the loop and diminish the amount of raw materials used in their production systems. However, implementing RL implies dealing with its barriers. The purpose of this article is to focus on the recovery of EOL products that use mostly raw materials from the mining...

  20. Determination of Mineralization Zones Using Interpretation of IP and RS Data in The GarmabCopper Deposit (South Khorasan province

    Mansour Adelpour


    Full Text Available Introduction The Garmab copper deposit is located northeast of Qaen (South Khorasan province in the1:100,000 scale map of Abiz in the eastern tectonic zone of Iran. It is hosted by Late Paleocene-Eocene lava flows consisting mainly of andesite, trachy¬andesite, andesite-basalt and basalt lavas, as well as pyroclastic rocks, including tuffs and ignimbrites. The Lut Block has undergone intense magmatic activitywith a variety of geochemical characteristics due to changing tectonic conditions (e.g., compression during subduction followed by tensional conditions; Karimpour et al., 2012; Zarrinkoub et al., 2012. The Lut Block has a great potential for the discovery of new mineral deposits, like the Mahrabad and Khonik porphyry copper-gold deposits (Malekzadeh shafarodi, 2009, the Dehsalam porphyry copper deposit (Arjmandzadeh, 2011, high sulfidation epithermal gold deposits such as Chah Shalghami (Karimpour, 2005 and IOCG deposits such as Kuh-E-Zar and Qaleh Zari (Mazlomi et al., 2008. Materials and methods After field studies of the Garmab area, 32 thin sections and 21 polished sections were prepared for petrological and mineralogical studies.In addition, 10 least-altered and fractured samples of volcanic rocks were selected for geochemical studies. Major oxides were determined using XRF analyses at the Zarazma laboratory. Induced polarization and resistivity geophysical data were collected and correlated with geological and alteration maps. The geophysical datawere collectedfrom 420 individual points, using a dipole-dipole arrangement along five profiles separated 60m apart.This covered the study area entirely. After a change in the mineralization trend was observed,additional profileswere designed, twoon bearings of 25º and three on 75º. Results The Garmab volcanic rocks exhibit typical geochemical characteristics of subduction zone magmas including strong enrichment in LILE and depletion in HFSE. Based on the discrimination plot of Irvine and