Sample records for carnotite

  1. Vibrational spectrum of synthetic carnotite

    Energy Technology Data Exchange (ETDEWEB)

    Baran, E J; Botto, I L [La Plata Univ. Nacional (Argentina). Facultad de Ciencias Exactas


    The infrared and laser-Raman spectra of synthetic carnotite, K/sub 2/((UO/sub 2/)/sub 2/V/sub 2/O/sub 8/), are reported and discussed. Force constants for the terminal V-O bonds as well as for the UO/sub 2//sup 2 +/ ions are evaluated. From the spectroscopic data, a U-O bond length of 1.81 A is estimated for the uranyl ion in this compound.

  2. Extraction of uranium from carnotite/tyuyamunite

    International Nuclear Information System (INIS)

    Li Shengnian; Fang Xuxia


    According to the characters of a carnotite/tyuyamunite and chemical properties of vanadate, the technological process, heap leaching-ion exchange-precipitation, is adopted for extracting uranium. It has been proved through laboratory test and industrial trial production that process is simple and convenient in method, advanced in technology, simple in equipment, and the product quality conforms to the criterion. The technological process is applied to small-sized hydrometallurgy plant at mine

  3. Chemical ore genesis models for the precipitation of carnotite in calcrete

    International Nuclear Information System (INIS)

    Mann, A.W.


    An investigation was carried out on the chemical mechanism responsible for the precipitation of carnotite in calcrete. The correct interpretation of uranium and vanadium movement in groundwater may only be possible after a careful and detailed evaluation of the occurrence (or non-occurrence) of many other uranium-vanadium complex salts, particularly those of calcium. It is concluded that a redox controlled mechanism for the precipitation of carnotite from groundwaters seem most likely. (R.L.)

  4. Correlation and origin of carnotite occurrences in the southern Nevada region

    International Nuclear Information System (INIS)

    Johnson, C.L.


    Carnotite [K 2 (UO 2 ) 2 (VO 4 ) 2 .3H 2 O] is recognized at seven localities in the southern Nevada region. These general areas of occurrence are the Jean-Sloan Calcrete, Hidden Valley Calcrete, Hualapai Limestone, Boulder City ''fossil water table'', Horse Spring Formation type locality, Mormon Mesa Caliche, and exposures of the Willow Tank thrust fault. The carnotite occurrences pre-date the 3.80 MY (million years before present) basalt at Sandy Pint, post-date an 8.66 MY tuff that underlies the Hualapai Limestone, and are approximately coeval with the 5.84 MY Fortification Basalt. Analysis of the Th/U ratios from 2045 dry stream sediment samples collected during the National Uranium Resource Evaluation (NURE) Program indicates uranium depletion in Precambrian terrain of the region and enrichment in areas where carnotite is observed. Anomalous vanadium in dry stream sediment samples is associated with intermediate and mafic Cenozoic volcanic rocks of pre-Colorado River age, and to a lesser extent with uratic Precambrian rocks. Correlation of the Jean-Sloan Calcrete, Hidden Valley Calcrete, Mormon Mesa Caliche, Hualapai Limestone, and Boulder City ''fossil water table'' is proposed based on elevation, relief, and inferred common age and origin. Carnotite studies have provided recognition criteria for facies of a regional geomorphic surface that formed in association with sluggish shallow groundwater flow in axial drainage systems in the Late Miocene. Carnotite and gypsum were deposited in disrupted by normal faulting and climatic conditions become increasingly arid 5-6 MY ago. Major geologic events that approximately coincide with the formation of the carnotite occurrences include the Messinian Crisis, opening of the Gulf of California, and uplift of the Sierra Nevada

  5. Genesis principles for the precipitation of carnotite in calcrete drainages in western Australia

    International Nuclear Information System (INIS)

    Mann, A.W.; Deutscher, R.L.


    Carnotite, K;sub 2;(UO;sub 2;);sub 2;V;sub 2;O;sub 8;*3H;sub 2;O, is a potassium uranyl-vanadate which commonly occurs as a secondary accessory mineral around reduced uranium ore deposits. In recent years, however, carnotite has been recognized to be an important primary ore mineral in the calcreted drainage systems of the arid and semiarid portions of the Yilgarn Block in Western Australia. This paper describes some of the genetic principles which have been derived from a combined drainage-catchment and laboratory experimental study of the solution geochemistry of uranium and vanadium as it applies in particular to the drainage systems of semiarid and arid Western Australia

  6. Crystal structure study of new lanthanide silicates with silico-carnotite structure

    International Nuclear Information System (INIS)

    Piccinelli, F.; Lausi, A.; Speghini, A.; Bettinelli, M.


    The crystal structures of new rare earth-based silicate compounds (Ca 3 Eu 2 Si 3 O 12 , Ca 3 Gd 2 Si 3 O 12 , Ca 3 Dy 2 Si 3 O 12 , Ca 3 Er 2 Si 3 O 12 and Ca 3 Lu 2 Si 3 O 12 ) have been determined using powder X-ray diffraction. From Rietveld refinement calculations on the collected powder patterns we observe a different distribution of the rare earth ions on the three available crystal sites characterized by different coordination numbers, depending on the ionic radius of the rare earth ion. The reasons of the instability of the silico-carnotite structure for lanthanide ions larger than Eu 3+ have been deduced. In addition, in order to detect crystal phase transitions, the powder patterns of Ca 3 Eu 2 Si 3 O 12 and Ca 3 Sm 2 Si 3 O 12 samples have been collected as a function of the temperature (RT-1000 °C range), but no phase transitions have been observed. - Graphical abstract: Synchrotron X-ray diffraction allows us the accurate determination of the RE 3+ ions distribution on the three available crystal sites of the silico-carnotite structure. Highlights: ► The structure of the Ca 3 M 2 Si 3 O 12 (M=Eu, Gd, Dy, Er and Lu) was determined. ► Different distribution of RE 3+ ions on the three available crystal sites was observed. ► The instability of the silico-carnotite structure for RE=La→Sm was discussed.

  7. Use of mineral/solution equilibrium calculations to assess the potential for carnotite precipitation from groundwater in the Texas Panhandle, USA (United States)

    Ranalli, Anthony J.; Yager, Douglas B.


    This study investigated the potential for the uranium mineral carnotite (K2(UO2)2(VO4)2·3H2O) to precipitate from evaporating groundwater in the Texas Panhandle region of the United States. The evolution of groundwater chemistry during evaporation was modeled with the USGS geochemical code PHREEQC using water-quality data from 100 groundwater wells downloaded from the USGS National Water Information System (NWIS) database. While most modeled groundwater compositions precipitated calcite upon evaporation, not all groundwater became saturated with respect to carnotite with the system open to CO2. Thus, the formation of calcite is not a necessary condition for carnotite to form. Rather, the determining factor in achieving carnotite saturation was the evolution of groundwater chemistry during evaporation following calcite precipitation. Modeling in this study showed that if the initial major-ion groundwater composition was dominated by calcium-magnesium-sulfate (>70 precent Ca + Mg and >50 percent SO4 + Cl) or calcium-magnesium-bicarbonate (>70 percent Ca + Mg and  mHCO3− + 2mCO3−2) carnotite saturation was achieved. If, however, the initial major-ion groundwater composition is sodium-bicarbonate (varying amounts of Na, 40–100 percent Na), calcium-sodium-sulfate, or calcium-magnesium-bicarbonate composition (>70 percent HCO3 + CO3) and following the precipitation of calcite, the concentration of calcium was less than the carbonate alkalinity (2mCa+2 < mHCO3- + 2mCO3−2) carnotite saturation was not achieved. In systems open to CO2, carnotite saturation occurred in most samples in evaporation amounts ranging from 95 percent to 99 percent with the partial pressure of CO2 ranging from 10−3.5 to 10−2.5 atm. Carnotite saturation occurred in a few samples in evaporation amounts ranging from 98 percent to 99 percent with the partial pressure of CO2 equal to 10−2.0 atm. Carnotite saturation did not occur in any groundwater with the system closed

  8. Pulmonary function evaluations of dogs exposed to uranium ore dust

    International Nuclear Information System (INIS)

    Loscutoff, S.M.; Buschbom, R.L.; Palmer, R.F.; Cross, F.T.


    Pulmonary function evaluations were conducted on dogs exposed to carnotite uranium ore dust. Significant changes were detected in the slope of the single-breath N 2 washout curve, suggesting an uneven distribution of ventilation

  9. Hydrology of uranium deposits in calcretes of western Australia

    International Nuclear Information System (INIS)

    Gaskin, A.J.; Butt, C.R.M.; Deutscher, R.L.; Horwitz, R.C.; Mann, A.W.


    Carnotite is the principal uranium mineral occurring in the calcreted trunk valleys of the ancient drainage system which extends over 400,000 sq km of south-western Australia. The calcretes, accumulations of calcium and magnesium carbonates up to 100 km long, 5 km wide, and 20 m thick, are discontinuous in character but act as aquifers for groundwaters of relatively low salinity that flow sluggishly to playa lakes. Catchment basins draining large areas of Precambrian granitic rocks can yield up to 200 parts per billion of uranium in the oxidizing environment of the water at shallow depth near the base of the calcretes. Where the product of the concentrations of active ion species of uranium, vanadium, and potassium exceeds the solubility product of carnotite, this mineral precipitates in fissures or between the carbonate and clay particles. Vanadium appears to be generally deficient in the upper levels of the aquifers; however, where it has been supplied at the required concentration from deeper reduced waters, forced up, for example, by a bar of resistant bedrock, carnotite mineralization has occurred. The incongruent dissolution of carnotite liberates vanadium preferentially. Some carnotite deposits currently are being leached and redeposited downstream. Where calcrete channels reach salt lakes, great increases in the activity of calcium and potassium promote further carnotite deposition by the decomplexing of uranyl carbonate complexes carried down the aquifers. Many areas of carnotite mineralization are now known. The largest, at Yeelirre, contains 46,000 MT of U 3 O 8 at an average grade of 0.15%. Extraction from the ore is hampered by the carbonate content and the presence of illite-montmorillonite clay phases, but alkaline leach techniques are practicable. An appreciable proportion of the carnotite, in an extremely fine-grained form, can be associated with the clay fraction

  10. Margaritasite: a new mineral of hydrothermal origin from the Pena Blanca uranium district, Mexico. (United States)

    Wenrich, K.J.; Modreski, P.J.; Zielinski, R.A.; Seeley, J.L.


    Margaritasite, (Cs,K,H3O)2(UO2)2V2O8.nH2O (where Cs > K, H3O and n approx 1), a 10.514, b 8.425, c 7.25 A, beta 106.01o, P21/a, Z = 2, is a newly recognized uranium ore mineral named for the Margaritas deposit, Pena Blanca uranium district, Chihuahua, Mexico, at which it was discovered. A Cs-rich analogue of carnotite, margaritasite is the natural equivalent of synthetic Cs-uranyl vanadate (A.M. 43- 799, 50-825). A fine-grained yellow mineral, it is most easily distinguished from carnotite by XRD; X-ray powder patterns (CuKalpha radiation) show that the (001) reflection of margaritasite lies at 12.7o (2theta ), while that of carnotite is found at 13.8o (2theta ). The shift of the (001) reflection in margaritasite reflects the structural changes caused when Cs occupies the sites filled by K in carnotite. Synthesis experiments indicate that margaritasite also differs from carnotite in a higher-T hydrothermal origin. Chemical analyses and XRD data for margaritasite and synthetic Cs- carnotite, and chemical analyses for rocks from Sierra Pena Blanca and vicinity, are tabulated.-J.A.Z.

  11. Petrology, mineralogy and geochemistry of surficial uranium deposits

    International Nuclear Information System (INIS)

    Pagel, M.


    A comprehensive understanding of the petrology, mineralogy, and geochemistry of surficial uranium ore deposits is important for developing prospecting and evaluation strategies. Carnotite is the main uranium mineral and is found in those deposits that have the greatest potential uranium resources. The following uranium-bearing minerals have been reported to occur in surficial deposits: carnotite, tyuyamunite, soddyite, weeksite, haiweeite, uranophane, betauranophane, metaankoleite, torbernite, autunite, phosphuranylite, schroeckingerite, Pb-V-U hydroxide (unnamed mineral), uraninite and organourano complexes. The interrelationships between some of the minerals of the host rocks (especially the clays) are not well understood. (author)

  12. Uranium occurence in nature: Geophysical prospecting, and its occurence in Syria

    International Nuclear Information System (INIS)

    Al-Haj Rasheed, Zaki


    A general idea about naturaly occured uranium minerals such as uranite, pechblende, carnotite, coffinit, and bronnerit is given. At the same time, different geophysical methods and detecting devices applied for uranium exploration have been demonstrated. Investigations and studies carried out in Syria point to a uranium content of 100 ppm in the exploited Syrian phosphorite. 1 fig., 1 tab

  13. Energy transfer processes in Ca.sub.3./sub.Tb.sub.2-x./sub.Eu.sub.x./sub.Si.sub.3./sub.O.sub.12./sub. (x = 0–2)

    Czech Academy of Sciences Publication Activity Database

    Carrasco, I.; Bartosiewicz, Karol; Nikl, Martin; Piccinelli, F.; Bettinelli, M.


    Roč. 48, Oct (2015), s. 252-257 ISSN 0925-3467 EU Projects: European Commission(XE) 316906 - LUMINET Institutional support: RVO:68378271 Keywords : phosphors * silico-carnotite * luminescence * energy transfer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.183, year: 2015

  14. Mineral transformations during the dissolution of uranium ore minerals by dissimilatory metal-reducing bacteria (United States)

    Glasauer, S.; Weidler, P.; Fakra, S.; Tyliszczak, T.; Shuh, D.


    Carnotite minerals [X2(UO2)2(VO4)2]; X = K, Ca, Ba, Mn, Na, Cu or Pb] form the major ore of uranium in the Colorado Plateau. These deposits are highly oxidized and contain U(VI) and V(IV). The biotransformation of U(VI) bound in carnotite by bacteria during dissimilatory metal reduction presents a complex puzzle in mineral chemistry. Both U(VI) and V(V) can be respired by metal reducing bacteria, and the mineral structure can change depending on the associated counterion. We incubated anaerobic cultures of S. putrefaciens CN32 with natural carnotite minerals from southeastern Utah in a nutrient-limited defined medium. Strain CN32 is a gram negative bacterium and a terrestrial isolate from New Mexico. The mineral and metal transformations were compared to a system that contained similar concentrations of soluble U(VI) and V(V). Electron (SEM, TEM) microscopies and x-ray spectromicroscopy (STXM) were used in conjunction with XRD to track mineral changes, and bacterial survival was monitored throughout the incubations. Slow rates of metal reduction over 10 months for the treatment with carnotite minerals revealed distinct biotic and abiotic processes, providing insight on mineral transformation and bacteria-metal interactions. The bacteria existed as small flocs or individual cells attached to the mineral phase, but did not adsorb soluble U or V, and accumulated very little of the biominerals. Reduction of mineral V(V) necessarily led to a dismantling of the carnotite structure. Bioreduction of V(V) by CN32 contributed small but profound changes to the mineral system, resulting in new minerals. Abiotic cation exchange within the carnotite group minerals induced the rearrangement of the mineral structures, leading to further mineral transformation. In contrast, bacteria survival was poor for treatments with soluble U(VI) and V(V), although both metals were reduced completely and formed solid UO2 and VO2; we also detected V(III). For these treatments, the bacteria

  15. Denver radium site's - Case history

    International Nuclear Information System (INIS)

    Topolski, T.T.


    In developing this case history of the Denver radium sites, an attempt is made to establish the Colorado carnotite connection from the point of discovery to early development and its eventual role in the inception of the National Radium Institute and Denver's radium legacy. Early exploitive mining activities and the exportation of the highest grades of uranium ore to Europe greatly disturbed key officials at the U.S. Bureau of Mines. With its proximity to known carnotite deposits and industrial capacity, Denver's destiny as one of America's early radium production centers became a reality by 1914. With African pitchblend discoveries, Belgium competition spelled the beginning of the end of Denver's romance with radium by 1920. The sites where Denver made or used its radium were lost in obscurity for 60 years and rediscovered in 1979. Thirty one sites and a characterization of their radioactive impact are now a part of the Superfund National Priorities listing for eventual cleanup

  16. Uranium occurences in calcrete and associated sediments in Western Australia

    International Nuclear Information System (INIS)

    Butt, C.R.M.; Horwitz, R.C.; Mann, A.W.


    The report is a compilation of data pertaining to the occurence and distribution of uranium mineralization in calcretes and associated sediments in Western Australia and contains brief descriptions of many of the calcrete-uranium occurences, including some of the most minor. Virtually all calcretes in the region are liable to contain traces of uranium mineralization, visible as coatings of carnotite. The locations of the uranium occurences are shown on a map which features the distribution of calcrete

  17. Radioactive mineral deposits

    Energy Technology Data Exchange (ETDEWEB)


    This publication was designed as a guide for uranium and thorium prospectors in Australia. Physical properties, such as color, streak, luster, hardness, fracture, and specific gravity of the uranium and thorium-bearing minerals are summarized and the various methods suitable for detecting radioactivity in minerals are described. Two colored plates show samples of pitchblende (uraninite), autunite, carnotite, monazite, and others of the most important minerals sources of uranium and thorium.

  18. Geology of the Horse Range Mesa quadrangle, Colorado (United States)

    Cater, Fred W.; Bush, A.L.; Bell, Henry; Withington, C.F.


    The Horse Range Mesa quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of the quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary strictures in sandstones of favorable composition.

  19. Possible variations on the calcrete-gypcrete uranium model

    International Nuclear Information System (INIS)

    Carlisle, D.


    Genetic models and favorability criteria for calcrete and gypcrete uranium deposits based upon Yeelirrie and other occurrences in Western Australia and upon Langer Henirich and others in Namibia-South West Africa are summarized. Viable analogues of these world-class deposits have not yet been found in USA even though several of the favorable conditions occur in the southwest. A principal deterrent to economic concentration has been tectonic instability. But even in the most favorable areas it is not clear that climates have ever been sufficiently similar to that of the valley-calcrete region of Western Australia. Extensive, thick valley (nonpedogenic) calcretes such as those which host the carnotite in Australia and in Namibia have not been documented here. Nevertheless, submarginal occurrances of carnotite have been found in southwestern United States in small bodies of nonpedogenic and mixed pedogenic-nonpedogenic calcrete. Much of the study is based upon occurrences of carnotite-bearing calcrete and calcrete-gypcrete in the Republic of South Africa. Several of these are described briefly. Some reference is also made to new occurrences and to new data on previously described occurrences on the Namib Desert. Possible variations on the Western Australian and Namibia-South West Africa models which are considered are capillary rise of U in solution, addition of new uraniferous sediment over a calcrete, lateral access of U into a pedogenic calcrete, reworking of U from a weekly mineralized pedogenic calcrete or gypcrete into a new or reconstituted calcrete, or into an unrelated environment for fixation of U

  20. Possible variations on the calcrete-gypcrete uranium model

    Energy Technology Data Exchange (ETDEWEB)

    Carlisle, D.


    Genetic models and favorability criteria for calcrete and gypcrete uranium deposits based upon Yeelirrie and other occurrences in Western Australia and upon Langer Henirich and others in Namibia-South West Africa are summarized. Viable analogues of these world-class deposits have not yet been found in USA even though several of the favorable conditions occur in the southwest. A principal deterrent to economic concentration has been tectonic instability. But even in the most favorable areas it is not clear that climates have ever been sufficiently similar to that of the valley-calcrete region of Western Australia. Extensive, thick valley (nonpedogenic) calcretes such as those which host the carnotite in Australia and in Namibia have not been documented here. Nevertheless, submarginal occurrances of carnotite have been found in southwestern United States in small bodies of nonpedogenic and mixed pedogenic-nonpedogenic calcrete. Much of the study is based upon occurrences of carnotite-bearing calcrete and calcrete-gypcrete in the Republic of South Africa. Several of these are described briefly. Some reference is also made to new occurrences and to new data on previously described occurrences on the Namib Desert. Possible variations on the Western Australian and Namibia-South West Africa models which are considered are capillary rise of U in solution, addition of new uraniferous sediment over a calcrete, lateral access of U into a pedogenic calcrete, reworking of U from a weekly mineralized pedogenic calcrete or gypcrete into a new or reconstituted calcrete, or into an unrelated environment for fixation of U.

  1. Development of uranium processing at Wiluna

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, D., E-mail: [Toro Energy Ltd., West Perth, WA (Australia); Dombrose, E. [Metallurgical Support Pty Ltd., Shelley, WA (Australia)


    Toro Energy Ltd. has identified a resource of 20.2 million tonnes at a grade of 548 ppm U{sub 3}O{sub 8} at Wiluna, Western Australia. Calcrete and clay delta formations host the uranium mineral carnotite. Initial studies indicate a mining operation is technically, environmentally and commercially viable. Increase in demand for uranium and a change in State Government policy on uranium mining have lead Toro to proceed with a bankable feasibility study and commence approvals with State and Federal Governments. This paper discusses how Toro arrived at the decision to utilise alkaline heap leach, a process not widely used, and how it is being developed. (author)

  2. Mineralogy and geochemistry of vanadium in the Colorado Plateau (United States)

    Weeks, A.D.


    The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin. ?? 1961.

  3. Mineral supplies for atomic energy

    Energy Technology Data Exchange (ETDEWEB)

    Fox, C S


    In a preliminary discussion the author describes the process of fission and discusses the materials required. Geological considerations are presented along with information regarding the occurrences of thorium and uranium deposits. The chief sources of uranium ore are the Belgian Congo, the Great Bear Lake in Canada, the Erzgebirge in Bohemia, and the low grade carnotite ore in Colorado, and possibly a deposit in Siberia. The monazite sands of Travancore are the most useful source of thoria today. The world's supply of uranium is somewhat under 10,000 tons of ore annually and thorium approximately 5,000 tons of suitable monazite sand.

  4. Hinkler Well - Centipede uranium deposits

    International Nuclear Information System (INIS)

    Crabb, D.; Dudley, R.; Mann, A.W.


    The Hinkler Well - Centipede deposits are near the northeastern margin of the Archean Yilgarn Block on a drainage system entering Lake Way. Basement rocks are granitoids and greenstones. The rocks are deeply weathered and overlain by alluvism. Granitoids, the probable uranium source, currently contain up to 25 ppm uranium, in spite of the weathering. The host calcrete body is 33 km long and 2 km wide. Uranium up to 1000 ppm occurs in carnotite over a 15 km by 2.5 km area. (author)

  5. Lake Austin uranium deposit, Western Australia

    International Nuclear Information System (INIS)

    Heath, A.G.; Deutscher, R.L.; Butt, C.R.M.


    The Lake Austin uranium deposit is a calcrete type deposit in the Yilgarn Block, near Cue, in a catchment area of granitoids and greenstones. The uranium is in valley fill and the sediments of the Lake Austin playa. The mineralization occurs over 1 to 6 meter thickness close to the water table in calcrete overlying clays and/or weathered bedrock. The principal uranium mineral is carnotite. Waters in nearby channels have an uranium content of over 30 ppb. The chloride content of the water increases downstream in the nearby drainages, as does the uranium and vanadium content. (author)

  6. Uraniferous surficial deposits in Southern Africa

    International Nuclear Information System (INIS)

    Hambleton-Jones, B.B.; Levin, M.; Wagener, G.F.


    Surficial uranium deposits are located in the north-western Cape Province of South Africa, in the Namib Desert east of Walvis Bay in South West Africa/Namibia and in the Serule Block of Botswana. They have been classified into the valley-fill, lacustrine, and pedogenic types. Carnotite is the main uranium-bearing mineral in the larger surficial deposits, with other minerals such as soddyite and phosphuranylite occurring locally. Uraninite or urano-organic complexes occur in the reducing environments of the diatomaceous earth, peat-rich deposits. Economically, the valley-fill type is the most important, with the largest deposits occurring in South West Africa/Namibia. In South West Africa/Namibia the valley-fill surficial uranium deposits occur in the Tumas and Langer Heinrich formations of the Teriary to Recent Namib Group. The Tubas, Langer Heinrich, and Welwitchia deposits are discussed: in them, carnotite occurs in calcareous and gypsiferous fluvial gravels. The pedogenic deposit at Mile 72 occurs in weathered granite and overlying gypcrete and has little economic potential. The economic potential of the surficial deposits in the north-western Cape Province is very limited in comparison with their South West African/Namibian counterparts, but the most important deposits are the lacustrine type, in particular those containing peat and diatomaceous earth. The mechanisms for the precipitation and preservation of the uranium are discussed

  7. Regional exploration for channel and playa uranium deposits in Western Australia using groundwater

    International Nuclear Information System (INIS)

    Noble, R.R.P.; Gray, D.J.; Reid, N.


    Shallow calcrete aquifers in the central north of the Yilgarn Craton in Western Australia are the host to numerous secondary carnotite U deposits. Sampling and analysis of approximately 1400 shallow aquifer groundwaters were conducted to test if U mineralisation of this type may be found using a >5 km sample spacing. Results show this can be achieved. All the economic deposits and most of the minor deposits and occurrences are associated with groundwater that has carnotite (KUO 2 VO 4 ) approaching or exceeding saturated conditions. Soluble U concentrations alone identified the largest deposit (Yeelirrie) and several smaller deposits, but this parameter was not as successful as the mineral saturation indices. Palaeodrainage distribution and thickness of cover combined with surface drainage and catchment boundaries provided background information of U primary sources and for areas with the highest exploration potential for channel and playa U deposits. Granites in the SE of the study area are less prospective with regard to secondary U deposits. Groundwater geochemistry in conjunction with palaeodrainage mapping may greatly improve exploration through cover where radiometric geophysics is not effective. The study of regional, shallow groundwater for U shows multiple benefits for mineral exploration, the economy and potable water quality.

  8. Distribution of calcretes and gypcretes in southwestern United States and their uranium favorability, based on a study of deposits in Western Australia and South West Africa (Namibia)

    International Nuclear Information System (INIS)

    Carlisle, D.; Merifield, P.M.; Orme, A.R.; Kohl, M.S.; Kolker, O.; Lunt, O.R.


    Calcrete, dolocrete, and gypcrete carnotite are abundant in western Australia and Namib Desert, although only a few are of ore grade. The geology of these deposits are described. A genetic classification of calcretes emphasizing uranium favorability was developed, based on the distinction between pedogenic and nonpedogenic processes. Similarities between western Australia and South West Africa give support for the conclusions that lateral transport of U in groundwater is essential to ore deposition and that bedrock barriers or constrictions which narrow the channel of subsurface flow or force the water close to the land surface, greatly favor the formation of uraniferous calcretes. Criteria for uranium favorability deduced from the Australian and South West African studies were applied in a preliminary way to the southern Basin and Range Province of U.S. The procedure is to search for areas in which nonpedogenic calcrete or gypcrete may have developed. A caliche distribution map was compiled from soil survey and field data. Many areas were visited and some of the more interesting are described briefly, including parts of Clark County, Nevada, with occurrences of carnotite in calcrete

  9. Distribution of calcretes and gypcretes in southwestern United States and their uranium favorability, based on a study of deposits in Western Australia and South West Africa (Namibia)

    Energy Technology Data Exchange (ETDEWEB)

    Carlisle, D.; Merifield, P.M.; Orme, A.R.; Kohl, M.S.; Kolker, O.; Lunt, O.R.


    Calcrete, dolocrete, and gypcrete carnotite are abundant in western Australia and Namib Desert, although only a few are of ore grade. The geology of these deposits are described. A genetic classification of calcretes emphasizing uranium favorability was developed, based on the distinction between pedogenic and nonpedogenic processes. Similarities between western Australia and South West Africa give support for the conclusions that lateral transport of U in groundwater is essential to ore deposition and that bedrock barriers or constrictions which narrow the channel of subsurface flow or force the water close to the land surface, greatly favor the formation of uraniferous calcretes. Criteria for uranium favorability deduced from the Australian and South West African studies were applied in a preliminary way to the southern Basin and Range Province of U.S. The procedure is to search for areas in which nonpedogenic calcrete or gypcrete may have developed. A caliche distribution map was compiled from soil survey and field data. Many areas were visited and some of the more interesting are described briefly, including parts of Clark County, Nevada, with occurrences of carnotite in calcrete. (DLC)

  10. Effect of pH change on the primary uran-mica mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Shmariovich, E M; Zhil' tsova, I G; Pakul' nis, G V; Shugina, G A [Ministerstvo Geologii SSR, Moscow


    Conditions of the formation of ore bodies of hexavalent uranium minerals represented by uranyl vanadates and phosphates which are primary and sedimented from low temperature solutions (carnotite deposits in calcretes and carnotite - autunite deposits in black shale formations) are considered. Thermodynamic curves of the solubility dependence of various uranyl minerals on pH medium in the absence of SO/sub 4//sup 2 -/ and CO/sub 3//sup 2 -/ ions and for sulphate-carbonate solutions have been calculated using dissociation constants of corresponding acids and 0/f(298.15) values. It has been ascertained that uranyl mineral compounds according to the dependence of their solubility on ph medium form a distinct series from molybdates through arsenates, phosphates, vanadates and silicates to minerals of uranophane and kasolite group. It is shown that during the formation of infiltration deposits with uranyl mineralization a decisive role is played by the contrast change of pH value of medium caused by the presence of acid geochemical barrier (uranyl molybdates, arsenates, phosphates and vanadates are precipitating) or neutralizing alkaline barriers (uran-mica and uranyl silicates are precipitating) on the path of movement of oxygen metal-bearing solutions.

  11. Summary of the mineralogy of the Colorado Plateau uranium ores (United States)

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


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

  12. Recovery of uranium low grade ores by froth flotation: study of the texture and synergetic effects of flotation reagents

    International Nuclear Information System (INIS)

    Duverger, Agathe


    Due to the energy growing demand, uranium low grade ores may be those exploited in the future. Uranium ores conventional treatment does not often use mineral processing such as concentration methods for reducing leaching reagent consumption. The aim of this work is to develop an upgrading process to improve the operating process (alkaline heap leaching) taking into account the mineralogical and textural variability of the ore. The Trekkopje deposit is composed of calcrete and a gypscrete. The uranium bearing mineral is carnotite (K 2 (UO 2 ) 2 [VO 4 ] 2 .3H 2 O). The gangue minerals are composed by silicates, such as quartz, feldspars, micas and Ca-minerals, calcite and gypsum (XRD and ICP-MS analysis). A SEM image processing was used to study the textural properties and the exposed free surface of mineral inclusions in clay clusters. In calcrete milled to -200 μm, 50 % of all carnotite is associated with clay clusters, which are composed by 98 % of palygorskite, 2 % of illite, montmorillonite, and interbedded clays (XRD and microprobe analysis). The carnotite grain size is 95 % less than 70 μm. Calcite is the main inclusion in clay clusters. Indeed, the calcite inclusions average rate in the clay clusters is 12 % and 5 % for carnotite inclusion. And the free exposed surface percentage of these minerals in clay clusters is 3 % and 6 %, thus indicating that the inclusions should not affect the behavior of mixed clay particles. However, ore flotation essays did not verify this hypothesis. Three minerals separation have been proposed based on the mineral ability to consume leaching reagents: separating Ca-minerals from silicates, palygorskite from gangue minerals and carnotite from gangue minerals. A study of silicates and Ca-minerals electrokinetic properties (electrophoresis) was carried out to select the collectors and the optimum pH range for selective flotation. Basic pH near neutral was proved to be optimal for the separation of gangue minerals with cationic

  13. Surficial uranium deposits in Somalia

    International Nuclear Information System (INIS)

    Briot, P.


    Surficial uranium deposits in Somalia are of the valley-fill calcrete type and occur in the arid Mudugh Province of the Dusa Mareb-El Bur region. They are located in a belt about 240 km in length which is orientated parallel to the north-south regional tectonic framework. The uranium resources of the region amount to about 5,000 t U 3 O 8 at an average grade of 0.1% U 3 O 8 . Basement rocks constitute a 7,000 m thick succession of Jurassic to Quaternary sediments of the Somalian Basin. Uranium mineralization in the form of carnotite occurs in the uppermost Mercia Series. The origin of the uranium and vanadium is unclear due to a shortage of the favourable source rocks. (author)

  14. EXTRACTION OF URANIUM (United States)

    Kesler, R.D.; Rabb, D.D.


    An improved process is presented for recovering uranium from a carnotite ore. In the improved process U/sub 2/O/sub 5/ is added to the comminuted ore along with the usual amount of NaCl prior to roasting. The amount of U/sub 2/O/ sub 5/ is dependent on the amount of free calcium oxide and the uranium in the ore. Specifically, the desirable amount of U/sub 2/O/sub 5/ is 3.2% for each 1% of CaO, and 5 to 6% for each 1% of uranium. The mixture is roasted at about 1560 deg C for about 30 min and then leached with a 3 to 9% aqueous solution of sodium carbonate.

  15. Design and construction of a system to determine Radon-222 through alpha spectroscopy

    International Nuclear Information System (INIS)

    Bonifacio M, J.


    The purpose of this work consists in the design a radon-222 gas measurement system utilizing a surface barrier detector with the objective to obtain a more accurate measurement for this isotope through an alpha particle spectrum and so to address as to avoid the activity influence of the descendants of short half-life, which are too beta particles emitters, already other methods it must be correction series to obtain the real value of radon activity. Here are presented the general properties properties of radon, the experimental part description indicating the design to measure the radon-222 gas and its parts, as well as too the standard separation of radium-226 starting from carnotite mineral. Finally, it is presented the results obtained with a discussion about it. (Author) results obtained with a discussion about it. (Author)

  16. Uranium traps in the phosphate bearing sudr chalk, in northeastern sinai, Egypt

    International Nuclear Information System (INIS)

    Hussein, H.A.; El-Aassy, I.E.; Mahdy, M.A.; Dabbour, G.A.; Mansour, M.Gh.; Morsy, A.M.


    The maastrichtian sudr formation in northeastern sinai is composed of three members, the lower chalk, the middle phosphate and chart-bearing and the upper chalk members. Lemon yellow secondary uranium mineralization, distributed in the lower chalk member and in some phosphate beds from the middle phosphate member are observed. The XRD analyses of some samples from the uranium bearing chalk and the phosphate beds showed the presence of the secondary uranium minerals carnotite, bergenite and upalite. The mode of uranium occurrences could be interpreted as a result of the phosphatic beds decomposition and their subjection to later diagenetic processes. Uranium leaching circulation from phosphate rocks led to the liberation of uranium from the phosphates, and vanadium from the bituminous material and clay minerals. These migrated and were deposited locally and within the underlying chalk beds which acted as a lithologic trap

  17. Solubility and dissolution kinetics study of uranium phosphates and vanadates: implications for the front end of the electronuclear cycle

    International Nuclear Information System (INIS)

    Cretaz, F.


    In the current context of restart of the nuclear energy, the needs in uranium are expected to increase significantly. Moreover, in a perspective of sustainable development, the exploitation, the treatment and the purification of uranium ores need to be optimized. It is thus necessary to determine reliable thermodynamic data (and especially solubility constants) for the systems of interest, especially uranium(VI) phosphates and vanadates. In this aim, a multi parametric study of the dissolution of meta-torbernite Cu 0.8 (H 3 O) 0.2 (UO 2 ) 2 (PO 4 ) 2.8 H 2 O, meta-autunite Ca(UO 2 ) 2 (PO 4 ) 2.6 H 2 O, meta-ankoleite K 2 (UO 2 ) 2 (PO 4 ) 2.6 H 2 O and carnotite K 2 (UO 2 ) 2 (VO 4 ) 2.3 H 2 O was undertaken. First, analogues of these four minerals were synthesized, based only on dry chemistry process for carnotite or on wet chemistry methods for the phosphate phases. They were then extensively characterized (in terms of structure, microstructure and chemical composition). It particularly highlighted the similar structures of such compounds. The anionic groups (PO 4 3- or V 2 O 8 6- ) and uranyl form parallel layers between which counter cations (Cu 2+ , Ca 2+ or K + ) and water molecules are inserted. However, the counter cations present in the interlayer space of the three phosphate phases present different lability. The synthetic phases were also compared to their natural analogues, except for meta-ankoleite, which allowed us to point out significant differences in the composition (presence of impurities in natural samples) and the morphology (grain size). The dissolution of these phases was then studied from a kinetic and thermodynamic point of view, through leaching tests in static and dynamic conditions, in various acid media (sulfuric, nitric and hydrochloric) and at different temperatures. In these conditions, the dissolution of meta-autunite was found to be un-congruent due to the precipitation of uranyl phosphate then avoiding the determination of

  18. Analysis of stream sediment reconnaissance data for mineral resources from the Montrose NTMS Quadrangle, Colorado

    International Nuclear Information System (INIS)

    Beyth, M.; Broxton, D.; McInteer, C.; Averett, W.R.; Stablein, N.K.


    Multivariate statistical analysis to support the National Uranium Resource Evaluation and to evaluate strategic and other commercially important mineral resources was carried out on Hydrogeochemical and Stream Sediment Reconnaissance data from the Montrose quadrangle, Colorado. The analysis suggests that: (1) the southern Colorado Mineral Belt is an area favorable for uranium mineral occurrences; (2) carnotite-type occurrences are likely in the nose of the Gunnison Uplift; (3) uranium mineral occurrences may be present along the western and northern margins of the West Elk crater; (4) a base-metal mineralized area is associated with the Uncompahgre Uplift; and (5) uranium and base metals are associated in some areas, and both are often controlled by faults trending west-northwest and north

  19. Design and construction of a system to determine Radon-222 through alpha spectroscopy; Diseno y construccion de un sistema para determinar Radon-222 mediante espectroscopia alfa

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio M, J. [Universidad Autonoma del Estado de Mexico. Facultad de Quimica. Toluca (Mexico)


    The purpose of this work consists in the design a radon-222 gas measurement system utilizing a surface barrier detector with the objective to obtain a more accurate measurement for this isotope through an alpha particle spectrum and so to address as to avoid the activity influence of the descendants of short half-life, which are too beta particles emitters, already other methods it must be correction series to obtain the real value of radon activity. Here are presented the general properties properties of radon, the experimental part description indicating the design to measure the radon-222 gas and its parts, as well as too the standard separation of radium-226 starting from carnotite mineral. Finally, it is presented the results obtained with a discussion about it. (Author) results obtained with a discussion about it. (Author)

  20. Multivariate statistical analysis of stream sediments for mineral resources from the Craig NTMS Quadrangle, Colorado

    International Nuclear Information System (INIS)

    Beyth, M.; McInteer, C.; Broxton, D.E.; Bolivar, S.L.; Luke, M.E.


    Multivariate statistical analyses were carried out on Hydrogeochemical and Stream Sediment Reconnaissance data from the Craig quadrangle, Colorado, to support the National Uranium Resource Evaluation and to evaluate strategic or other important commercial mineral resources. A few areas for favorable uranium mineralization are suggested for parts of the Wyoming Basin, Park Range, and Gore Range. Six potential source rocks for uranium are postulated based on factor score mapping. Vanadium in stream sediments is suggested as a pathfinder for carnotite-type mineralization. A probable northwest trend of lead-zinc-copper mineralization associated with Tertiary intrusions is suggested. A few locations are mapped where copper is associated with cobalt. Concentrations of placer sands containing rare earth elements, probably of commercial value, are indicated for parts of the Sand Wash Basin

  1. The Vanadium Window with special reference to Joseph and James Flannery's contribution to the American steel and radium industries

    International Nuclear Information System (INIS)

    Lubenau, J. O.; Mould, R. F.


    The discovery of vanadium is described and the founding of the American Vanadium Company by Joseph Flannery (1867-1920) and its headquarters building in Pittsburgh in which was the stained glass window depicting the origin of the name Vanadium. Company orders for vanadium steel were obtained for the Panama canal and from Henry Ford. When his sister was diagnosed with cancer, Joseph Flannery withdrew from his vanadium interests and founded the Standard Chemical and Radium Chemical Companies which were the major suppliers of radium in the USA in the 1920s (before the Union Minicre du Haut Katanga commenced its commercial operations), processed from American mined carnotite in Colorado and Utah. Significant contributions to these enterprises involving vanadium and radium were also made by Joseph's elder brother, James Flannery (1848-1920). (author)

  2. Design and construction of a system to determine Radon-222 through alpha spectroscopy; Diseno y construccion de un sistema para determinar Radon-222 mediante espectroscopia alfa

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio M, J [Universidad Autonoma del Estado de Mexico. Facultad de Quimica. Toluca (Mexico)


    The purpose of this work consists in the design a radon-222 gas measurement system utilizing a surface barrier detector with the objective to obtain a more accurate measurement for this isotope through an alpha particle spectrum and so to address as to avoid the activity influence of the descendants of short half-life, which are too beta particles emitters, already other methods it must be correction series to obtain the real value of radon activity. Here are presented the general properties properties of radon, the experimental part description indicating the design to measure the radon-222 gas and its parts, as well as too the standard separation of radium-226 starting from carnotite mineral. Finally, it is presented the results obtained with a discussion about it. (Author) results obtained with a discussion about it. (Author)

  3. Cleaning up the Streets of Denver

    International Nuclear Information System (INIS)

    Stegen, R.L.; Wood, T.R.; Hackett, J.R.; Sogue, A.


    Between 1913 and 1924, several Denver area facilities extracted radium from carnotite ore mined from the Paradox basin region of Colorado. Tailings or abandoned ores from these facilities were apparently incorporated into asphalt used to pave approximately 7.2 kilometers (4.5 miles) of streets in Denver. A majority of the streets are located in residential areas. The radionuclides are bound within the asphalt matrix and pose minimal risk unless they are disturbed. The City and County of Denver (CCoD) is responsible for controlling repairs and maintenance on these impacted streets. Since 2002, the CCoD has embarked on a significant capital improvement project to remove the impacted asphalt for secure disposal followed by street reconstruction. To date, Parsons has removed approximately 55 percent of the impacted asphalt. This paper discusses the history of the Denver Radium Streets and summarizes on-going project efforts. (authors)

  4. Major uranium provinces: Yilgarn block and Gascoyne Province, Western Australia

    International Nuclear Information System (INIS)

    Butt, C.R.M.


    The Archaean Yilgarn Block and the adjacent Proterozoic Gascoyne Province, Western Australia, form the basement and source rocks for numerous occurrences of surficial uranium mineralization, the largest being the Yeelirrie deposit (35 million tonnes at 0.15% U 3 O 8 ). The mineralization, almost exclusively in the form of carnotite, has been deposited in the regolith and appears to be less than 1 Ma old, with some deposits still forming. The nature and distribution of the mineralization are controlled by basement and surface geology, geomorphology, hydrology and climate, being restricted to deeply weathered, semi-arid terrain with granitoid source rocks. A few small occurrences in the Gascoyne Province may be pedogenic in origin but the majority, in the north of Yilgarn Block, occur in unrejuvenated palaeodrainage channels now choked by colluvial, alluvial and chemical sediments. These sediments, which are aquifers for the present, predominantly sub-surface, drainage, can exceed 10-15 m. Uranium released from the weathering granitoids has been transported in groundwaters in uranyl carbonate complexes and precipitated as carnotite where, (i) concentrations of uranium and potassium have been elevated by evaporation and, (ii) dissolved vanadium has been oxidized to the 5-valent state. Precipitation is in calcretes and associated sediments in the drainage axes, in 'chemical deltas' where the drainages enter playas and in the playas themselves. This style of mineralization was first recognized in 1969-1970 as the result of investigations into the source of radiometric anomalies delineated by airborne surveys. The majority of discoveries have similarly been by radiometric surveys but hydrogeochemical surveys have promise and may become important in future search for blind mineralization and/or young deposits not in radioactive equilibrium. (author). 61 refs, 6 figs

  5. Formerly utilized MED/AEC Sites Remedial Action Program. Radiological survey of the former VITRO Rare Metals Plant, Canonsburg, Pennsylvania. Final report. [Plant to extract radium and uranium

    Energy Technology Data Exchange (ETDEWEB)



    This 18-acre site was used from 1911 to 1922 to extract radium from carnotite ore, from 1930 to 1942 to extract radium and uranium salts from onsite residues and carnotite ore, and from 1942 to 1957 to recover uranium from various ores and scrap materials. The radiological survey was conducted in two phases, Phase I included measurement of radon and radon daughter concentrations in onsite buildings; concentrations measured in this part of the survey were all above guideline levels. Phase II consisted of measurement of surface contamination levels on the site, external gamma radiation levels at 1 m above surfaces on and near the site, radionuclide concentrations in surface and subsurface soil and water on and near the site, and radon concentrations in air at offsite locations. The results of the second phase of the survey indicate that large quantities of the radioactive wastes generated during radium and uranium recovery operations still remain on the site. Radium-bearing wastes are present in soil beneath or adjacent to each of the buildings on the site and in the top few feet of soil over almost the entire site, with some areas being contaminated to a depth of 16 ft or more. Alpha contamination levels, beta--gamma dose rates, and external gamma radiation levels in some areas of the buildings and outdoors on the site are above current federal guidelines concerning the release of property for unrestricted use. Concentrations of /sup 226/Ra in water in holes drilled on the site are above the maximum permissible concentration (MPC/sub w/). Also, measurements made offsite show that contamination from the site has spread to nearby offsite locations, and that there is significant atmospheric transport of /sup 222/Rn from the site.

  6. Inhalation of uranium ores

    International Nuclear Information System (INIS)

    Stuart, B.O.; Jackson, P.O.


    In previous studies the biological dispositions of individual long-lived alpha members of the uranium chain ( 238 U, 234 U and 230 Th) were determined during and following repeated inhalation exposures of rats to pitchblende (26 percent U 3 O 8 ) ore. Although finely dispersed ore in secular equilibrium was inhaled, 230 Th/ 234 U radioactivity ratios in the lungs rose from 1.0 to 2.5 during 8 weeks of exposures and increased to 9.2 by four months after cessation of exposures. Marked non-equilibrium levels were also found in the tracheobronchial lymph nodes, kidneys, liver, and femur. Daily exposures of beagle dogs to high levels of this ore for 8 days resulted in lung 230 Th/ 234 U ratios of >2.0. Daily exposures of dogs to lower levels (0.1 mg/1) for 6 months, with sacrifice 15 months later, resulted in lung and thoracic lymph node 230 Th/ 234 U ratios ranging from 3.6 to 9 and nearly 7, respectively. The lungs of hamsters exposed to carnotite (4 percent U 3 O 8 ) ore in current lifespan studies show 230 Th/ 234 U ratios as high as 2.0 during daily inhalation of this ore in secular equilibrium. Beagle dogs sacrificed after several years of daily inhalations of the same carnotite ore plus radon daughters also showed marked non-equilibrium ratios of 230 Th/ 234 U, ranging from 5.6 to 7.4 in lungs and 6.2 to 9.1 in thoracic lymph nodes. This pattern of higher retention of 230 Th than 234 U in lungs, thoracic lymph nodes, and other tissues is thus consistent for two types of uranium ore among several species and suggests a reevaluation of maximum permissible air concentrations of ore, currently based only on uranium content

  7. The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States (United States)

    Van Gosen, Bradley S.; Hall, Susan M.


    This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments.In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U3O8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U3O8.The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age.Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234U/238U activity ratios indicate two separate, distinct fluid sources.

  8. Occurrence, behavior and distribution of high levels of uranium in shallow groundwater at Datong basin, northern China

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Ya; Wang, Yanxin, E-mail:; Xie, Xianjun


    Geochemical investigations of uranium (U) occurrence in the environments were conducted at Datong basin of northern China. The results suggest that U contents were generally < 1 mg/kg for the igneous and metamorphic rocks, typically 2–5 mg/kg for the Carboniferous and Permian sedimentary rocks and around 3 mg/kg for sediments and topsoil, respectively. U in the Quaternary aquifer sediments may be primarily associated with carnotite from the Carboniferous and Permian coal-bearing clastic rocks around the basin. Shallow groundwater had U concentrations of < 0.02–288 μg/L (average 24 μg/L), with 24% of the investigated boreholes above the WHO provisional guideline of 30 μg/L for U in drinking water. Average U concentration for surface water was 5.8 μg/L. In oxidizing waters, uranyl (UO{sub 2}{sup 2+}) species is dominant and strongly adsorbed onto iron (hydro)xides, while it would be preferentially complexed with carbonate in the alkaline groundwater, forming highly soluble uranyl-carbonate complexes at Datong. Under reducing conditions, uranous (U(IV)) species is ready to precipitate or bind to organic matter, therefore having a low mobility. At the study area, high U groundwater (> 30 μg/L) occurs at the alluvial plains due to intermediate redox and enhanced alkaline conditions. The abnormally high levels of U in groundwater (> 100 μg/L) are locally found at the west alluvial plains. By contrast, U co-precipitation with secondary carbonate minerals like Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} in the dominant Ca–Mg–Na–HCO{sub 3} type groundwater may prevail at the east alluvial plains. Besides, bedrocks such as Carboniferous and Permian sedimentary rocks, especially the coal-bearing strata which have higher U contents at the west mountain areas may also account for the abnormally high levels of U in groundwater. - Highlights: • High U groundwater occurs at the alluvial plains of Datong basin. • Redox state, complexation and adsorption are responsible

  9. Biological effects of daily inhalation of radon and its short-lived daughters in experimental animals

    International Nuclear Information System (INIS)

    Palmer, R.F.; Stuart, B.O.; Filipy, R.E.


    Syrian golden hamsters, C57BL mice, and specific-pathogen-free rats were exposed simultaneously in groups of 16 animals each for 90 hours per week to aerosols consisting of radon plus 3000--6000 Working Levels of radon-daughters with and without 18 mg/m 3 carnotite uranium ore dust. Condensation nuclei concentrations ranged from 2000--4000 per ml and from 90,000--120,000 per ml in the chamber without and with uranium ore dust, respectively. At 4 months of exposure only one of the rodents remained alive. Histopathology of radon-daughter exposed mice includes acute interstitial pneumonitis, severe pulmonary congestion, and supperative rhinitis; mice inhaling radon-daughters with ore showed these lesions plus macrophage proliferation, alveolar septal cell hyperplasia, and bronchial epithelial hyperplasia. Hamsters inhaling radon-daughters showed proliferating lesions characterized by alveolar septal thickening, bronchiolar epithelial hyperplasia, septal fibrosis, and occasionally adenomatoid metaplasia and squamous metaplasia. Hamsters inhaling radon-daughters with ore dust showed similar effects plus granulomatous response and intense septal fibrosis. Rats inhaling radon-daughters showed lesions similar to those of hamsters but more focalized with classic radiation pneumonitis; rats exposed to radon-daughters with ore showed similar lesions, with greater consolidation and pneumoconiosis. These findings will be discussed in relation to pulmonary pathology in uranium miners

  10. Spectral pathways for exploration of secondary uranium: An investigation in the desertic tracts of Rajasthan and Gujarat, India (United States)

    Bharti, Rishikesh; Kalimuthu, R.; Ramakrishnan, D.


    This study aims at identifying potential zones of secondary uranium enrichment using hyperspectral remote sensing, γ-ray spectrometry, fluorimetry and geochemical techniques in the western Rajasthan and northern Gujarat, India. The investigated area has suitable source rocks, conducive past-, and present-climate that can facilitate such enrichment. This enrichment process involves extensive weathering of uranium bearing source rocks, leaching of uranyl compounds in groundwater, and their precipitation in chemical deltas along with duricrusts like calcretes and gypcretes. Spatial distribution of groundwater calcretes (that are rich in Mg-calcite) and gypcretes (that are rich in gypsum) along palaeochannels and chemical deltas were mapped using hyperspectral remote sensing data based on spectral absorptions in 1.70 μm, 2.16 μm, 2.21 μm, 2.33 μm, 2.44 μm wavelength regions. Subsequently based on field radiometric survey, zones of U anomalies were identified and samples of duricrusts and groundwater were collected for geochemical analyses. Anomalous concentration of U (2345.7 Bq/kg) and Th (142.3 Bq/kg) are observed in both duricrusts and groundwater (U-1791 μg/l, Th-34 μg/l) within the palaeo-delta and river confluence. The estimated carnotite Solubility Index also indicates the secondary enrichment of U and the likelihood of occurrence of an unconventional deposit.

  11. A non-pedological hypothesis for the processes of uranium mineralization in calcrete

    International Nuclear Information System (INIS)

    Briot, P.; Fuchs, Y.


    The non-pedological hypothesis presented for the origin of the uraniferous calcrete deposits in Western Australia is based on the premise that alluvial and calcareous lacustrine sediments were initially formed during earlier wet periods, evidence for which has been found in the fossil records. These were followed by subsequent epigenetic alteration accompanied by the precipitation of uranium mineralization during drier semi-arid periods. Typical examples of the processes involved were found in the Yeelirrie uranium deposit. During the latter semi-arid period, the limited surface flow which consisted of periodic flash flood conditions probably contributed marginally to the recharge of the groundwater, and consequently, semi-stagnant groundwater conditions evolved, particularly where the hydraulic gradient was extremely small, for example, for the Yeelirrie channel it is approximately 0.001. In addition, ponding of water behind a natural barrier caused the groundwater to evolve along the following geochemical sequence: mild alkalinity, weak oxidizing conditions, and oversaturation in dissolved elements. These hydrological and hydrogeochemical conditions induced the epigenetic alteration of the palustral/lacustrine limestone, bringing about dolomite neogenesis and the precipitation of carnotite. The source of the uranium in the calcretes and the groundwater of the Yeelirrie channel is considered to be the weathered outcrops of the breakaways along its margins. The genetic hypothesis proposed in this paper, although somewhat different from those described previously and elsewhere in this volume, could be applied to the other uranium-bearing calcretes in Mauritania, Namibia, and Somalia

  12. Reconnaissance for radioactive deposits in Alaska, 1953 (United States)

    Matzko, John J.; Bates, Robert G.


    During the summer of 1953 the areas investigated for radioactive deposits in Alaska were on Nikolai Creek near Tyonek and on Likes Creek near Seward in south-central Alaska where carnotite-type minerals had been reported; in the headwaters of the Peace River in the eastern part of the Seward Peninsula and at Gold Bench on the South Fork of the Koyukuk River in east-central Alaska, where uranothorianite occurs in places associated with base metal sulfides and hematite; in the vicinity of Port Malmesbury in southeastern Alaska to check a reported occurrence of pitchblende; and, in the Miller House-Circle Hot Springs area of east-central Alaska where geochemical studies were made. No significant lode deposits of radioactive materials were found. However, the placer uranothorianite in the headwaters of the Peace River yet remains as an important lead to bedrock radioactive source materials in Alaska. Tundra cover prevents satisfactory radiometric reconnaissance of the area, and methods of geochemical prospecting such as soil and vegetation sampling may ultimately prove more fruitful in the search for the uranothorianite-sulfide lode source than geophysical methods.

  13. The Yeelirrie calcrete uranium deposit, Western Australia

    International Nuclear Information System (INIS)

    Cameron, E.


    The Yeelirrie deposit, between Wiluna and Sandstone, lies in the Yilgarn block, in a catchment area of deeply weathered granites and greenstones. The host calcretes are a 1 to 1.5 km wide valley-fill in a long established drainage system, and are developed over a 85 km long distance. The calcretes are either earthy or procellaneous with voids. The deposit is sheetlike, some 9 km long and 5 to 1.5 km wide, averaging 3 m thick and is 4 to 8 meters below the surface, and immediately below the water table. The deposit has 52,500 tonnes of U 3 O 8 at an average grade of 0.15% U 3 O 8 . Carnotite is the only uranium mineral. Water movement in the area is largely subsurface in the calcrete, which is a good aquifer. Uranium concentrations of 100 to 450 ppb are found in the calcrete ground waters compared to background values of 5 to 10 ppb. (author)

  14. Genesis of Uranium in the younger granites of gabal abu hawis area, central eastern desert of Egypt

    International Nuclear Information System (INIS)

    Ahmed, F.Y.; Moharem, A.F.


    The younger granites cropping out in gabal abu hawis area are considered as uraniferous (fertile) granites (the fertile is mainly is mainly attributed to presence of radioactive zircon). Abu hawis granitic pluton is dissected by joints faults of different trends forming two mineralized shear zones in the northern peripheries and southern border. The younger granites hosting uranium mineralizations along the two mineralized shear zones. The uranium minerals include uranophane and carnotite. The altered granites have much lower Th/U ratios (0.03-0.10) than those of the fresh granites (1.69-2.05), indicating strong mobilization of uranium in this pluton by super-heated solutions that resulted from supergence meteoric water as well as U-addition by hypogene fluids. These solutions could pass through the structural network of fractures, joints and fault planes and have leached some of labile uranium from the surrounding rocks and/or the younger granites themselves. Then, changing in the physicochemical conditions of these solutions caused uranium precipitation as uranium minerals filling the cracks in the rock and/or adsorbed on the surface of clay minerals and iron oxides in the two shear zones

  15. Separation of Actinium 227 from the uranium minerals

    International Nuclear Information System (INIS)

    Martinez-Tarango, S.


    The purpose of this work was to separate Actinium 227, whose content is 18%, from the mineral carnotite found in Gomez Chihuahua mountain range in Mexico. The mineral before processing is is pre-concentrated and passed, first through anionic exchange resins, later the eluate obtained is passed through cationic resins. The resins were 20-50 MESH QOWEX and 100-200 MESH 50 X 8-20 in some cased 200-400 MESH AG 50W-X8, 1X8 in other cases. The eluates from the ionic exchange were electrodeposited on stainless steel polished disc cathode and platinum electrode as anode; under a current ODF 10mA for 2.5 to 5 hours and of 100mA for .5 of an hour. it was possible to identify the Actinium 227 by means of its descendents, TH-227 and RA-223, through alpha spectroscopy. Due to the radiochemical purity which the electro deposits were obtained the Actinium 227 was low and was not quantitatively determined. A large majority of the members of the natural radioactive series 3 were identified and even alpha energies reported in the literature with very low percentages of non-identified emissions were observed. We conclude that a more precise study is needed concerning ionic exchange and electrodeposit to obtain an Actinium 227 of radiochemical purity. (Author)

  16. Geochemistry of uranium in ground waters of the Conlara river Valley, San Luis and Cordoba provinces (Argentina)

    International Nuclear Information System (INIS)

    Nicolli, H.B.; Gamba, M.A.


    Geochemical characteristics of ground waters related with lixiviation, transport and precipitation of uranium in the Conlara river valley (provinces of San Luis and Cordoba (Argentina)) are studied. Anions and cations' distributions, together with hardness, specific conductivity, pH, Eh, and uranium and vanadium contents, have been studied. Those parameters characterize four hidrogeochemical facies along an E-W profile: a calcic strong bicarbonate facies, an alkaline-calcic bicarbonate facies, an alkaline sulfate facies, and a strong alkaline sulfate facies. An ''Interphase zone'' (transition from bicarbonate water to sulfate water), where changes in composition may define a geochemical environment capable of UO2 precipitation, has been determined. The chemical-Thermodynamic studies give a dominance of UDC and UTC complexs ions (even in sulfate waters), so they represent the 99% of present ions. Besides, the calculated values required for equilibrium with uraninite or carnotite resulted much greater than those obtained in the performed experiments. It means that the precipitation of those minerals requires either the presence of greate amounts of uranium or vanadium, or a reducing environment with Eh values smaller than the observed ones. Finally, the steps to be taken in future investigations are suggested in view to a drilling plan where: 1) Priority to the ''Interphase zone'' areas is given. 2) The deepest aquifers in Tertiary sediments of the basin have to be reached in order to get the convenient environmental conditions (i.e. smallest Eh values) for uranium or uranium-vanadium precipitation. (author) [es

  17. The Wiluna Uranium Project, Western Australia: Bringing a new project to the market

    International Nuclear Information System (INIS)

    Guthrie, V.


    The Wiluna Uranium Project is the first uranium mine in Western Australia to receive Government environmental approval since government policy was changed in 2008 to allow uranium mining in Western Australia. Located 960 km northeast of Perth in remote central Western Australia, the Wiluna Project comprises 76.5 million pounds U_3O_8 [~29,000 tU] in six shallow, calcrete-hosted carnotite uranium deposits. Mining is planned at a rate of 1.3 million tonnes annually to produce 2 million pounds U_3O_8 [~770 tU] production using an alkali leach process. The Project requires initial capital investment of AUD$315M and has an operating cost of US$29-31 per pound [~75-~80 USD/kgU]. During the four years it has taken to gain environmental approval, Toro also progressed technical studies to validate the economic and technical viability of the Project. These included the initial Preliminary Feasibility (PFS) to define the processing train; mining optimisation studies, a Resource Evaluation Pit (REP) and a commercial scale Pilot Plant to verify the mining and processing technologies; and finally, Phase 1 of the Definitive Feasibility Study (DFS) which focussed on the processing plant design. (author)

  18. Design and construction of a system to analyze Radon 222 by means of alpha spectroscopy

    International Nuclear Information System (INIS)

    Martinez, J.B.


    Design and construction of a system to measure gaseous Radon 222 which arise from a source of Radium 226 electrodeposited in a stainless disc is described. Such a system allows to differentiate the energies of radium where they come from, as well as energies of daughter products. In this way it is possible to have a more precise measure of the alpha activity of this isotope. The system was constructed in a stainless steel hermetic container made of the camera, a cape and a valve, the used sample was a standards of Radium 226 attained from carnotite ore. The Radon 222 alpha particles, as well as the alpha particles of its decay products namely Polonium 210. Polonium 218 and Polonium 214 were identified by a surface barrier detector. The results in this manner obtained shows clearly well definite peaks of Radon 222 and also peaks of the Radon 222 daughter products with energies of 5.43, 5.31, 6.0 and 7.69 Mev respectively. The system allows to separate and to indentify the energies of Radon and its daughter products coming directly from a standard solid sample of Radium 226 (Author)

  19. A brief history of the American radium industry and its ties to the scientific community of its early Twentieth Century

    International Nuclear Information System (INIS)

    Landa, E.R.


    Federally funded remedial action projects are presently underway in New Jersey and Colorado at sites containing 226 Ra and other radionuclides from radium-uranium ore extraction plants that operated during the early twentieth century. They are but the latest chapter in the story of an American industry that emerged and perished in the span of three decades. Major extraction plants were established in or near Denver (CO), Pittsburgh (PA), and New York City (NY) to process radium from ore that came largely from the carnotite deposits of western Colorado and eastern Utah. The staffs of these plants included some of the finest chemists and physicists in the nation, and the highly-refined radium products found a variety of uses in medicine and industry. The discovery of high-grade pitchblende ores in the Belgian Congo and the subsequent opening of an extraction plant near Antwerp, Belgium, in 1992, however, created an economic climate that put an end to the American radium industry. The geologic, chemical, and engineering information gathered during this era formed the basis of the uranium industry of the later part of the century, while the tailings and residues came to be viewed as environmental problems during the same period

  20. Evaluation of Uranium depositional system in sedimentary rocks of Sibolga formation, Tapanuli Tengah

    International Nuclear Information System (INIS)

    I Gde Sukadana; Heri Syaeful


    Uranium in nature formed in various deposit type, depends on its sources, process, and depositional environments. Uranium occurrence in Sibolga, hosted in sedimentary rocks of Sibolga Formation, is properly potential to develop; nevertheless, the depositional pattern and uranium mineralization process so far had not been recognized. The research aim is to determine the rock distribution patterns and the existence of uranium grade anomalies based on surface geology and borehole log data. Mineralization occurrences from borehole log data distributed from basalt conglomerate unit (Kgl 1), sandstone 1 unit (Bp 1), conglomerate 2 unit (Kgl 2), and sandstone 2 unit (Bp 2) with their distribution and thickness are thinning to the top. Mineralization distribution in the eastern area, mainly on Kgl 1 unit, dominated by detritus materials from epi-genetic depositional in the form of monazite which is formed along with the formation of granite as its source rock. Meanwhile, mineralization on the upper rocks units formed a channel pattern trending northeast-southwest, which formed in syn-genetic process consist of uraninite, carnotite, and coffinite. Sibolga Formation deposition originated from east to west and uranium deposit formed because of the differences of depositional environment from oxidation in the east to the more reductive in the southwest. The increasing of organic materials in southwest basin caused the reduction condition of depositional environment. (author)

  1. Surficial uranium deposits: summary and conclusions

    International Nuclear Information System (INIS)

    Otton, J.K.


    Uranium occurs in a variety of surficial environments in calcretes, gypcretes, silcretes, dolocretes and in organic sediments. Groundwater moving on low gradients generates these formations and, under favourable circumstances, uranium deposits. A variety of geomorphic settings can be involved. Most surficial deposits are formed in desert, temperate wetland, tropical, or transitional environments. The largest deposits known are in sedimentary environments in arid lands. The deposits form largely by the interaction of ground or surface waters on the geomorphic surface in favourable geologic terrains and climates. The deposits are commonly in the condition of being formed or reconstituted, or being destroyed. Carnotite is common in desert deposits while in wetland deposits no uranium minerals may be seen. Radioactive disequilibrium is common, particularly in wetland deposits. Granites and related rocks are major source rocks and most large deposits are in regions with enriched uranium contents, i.e. significantly greater than 5 ppm uranium. Uranium dissolution and transport is usually under oxidizing conditions. Transport in desert conditions is usually as a bicarbonate. A variety of fixation mechanisms operate to extract the uranium and form the deposits. Physical barriers to groundwater flow may initiate ore deposition. Mining costs are likely to be low because of the near surface occurrence, but there may be processing difficulties as clay may be present and the saline or carbonate content may be high. (author)

  2. Surficial uranium occurrences in relation to climate and physical setting

    International Nuclear Information System (INIS)

    Carlisle, D.


    Important surficial chemogenic uranium deposits develop within 1) calcretes, 2) simple evaporative environments and 3) bogs or similar organic environments (''young'' uranium). Calcrete occurrences are the largest, most novel and most dependent upon extreme aridity and geomorphic stability. Economic calcrete deposits are nonpedogenic, resulting from near-surface groundwater transport and lateral concentration of uranium, vanadium, potassium, calcium, and magnesium rather than from ordinary soil-forming processes. Their genesis is essentially observable in Western Australia where carnotite-bearing nonpedogenic calcrete is currently forming under a unique aridic soil moisture regime and where major deposits have formed under similar climates during the last few thousand years. Rainfall is less than 250mm annually, only 1/12 to 1/20 of potential evaporation and concentrated almost entirely in episodic late summer storms. Outside this region, under less arid conditions, only pedogenic calcretes form and they do not contain economic uranium. In southern Africa, calcrete and gypcrete uranium deposits, although Late Tertiary to Quaternary in age, are also nonpedogenic and appear to have formed under similar climatic constraints with local variations in geomorphology and calcrete morphology. (author)

  3. Geology and ore deposits of the Klondike Ridge area, Colorado (United States)

    Vogel, John David


    The region described in this report is in the northeastern part of the Colorado Plateau and is transitional between two major structural elements. The western part is typical of the salt anticline region of the Plateau, but the eastern part has features which reflect movements in the nearby San Juan Mountains. There are five major structural elements in the report area: the Gypsum Valley anticline, Dry Creek Basin, the Horse Park fault block, Disappointment Valley, and the Dolores anticline. Three periods of major uplift are recognized In the southeastern end of the Gypsum Valley anticline. Each was followed by collapse of the overlying strata. Erosion after the first two periods removed nearly all topographic relief over the anticline; erosion after the last uplift has not yet had a profound effect on the topography except where evaporite beds are exposed at the surface. The first and greatest period of salt flow and anticlinal uplift began in the late Pennsylvanian and continued intermittently and on an ever decreasing scale into the Early Cretaceous. Most movement was in the Permian and Triassic periods. The second period of uplift and collapse was essentially contemporaneous with widespread tectonic activity on. the northwestern side of the San Juan Mountains and may have Occurred in the Oligocene and Miocene epochs. Granogabbro sills and dikes were intruded during the middle or upper Tertiary in Disappointment Valley and adjoining parts of the Gypsum Valley and Dolores anticlines. The third and mildest period of uplift occurred in the Pleistocene and was essentially contemporaneous with the post-Hinsdale uplift of the San Juan Mountains. This uplift began near the end of the earliest, or Cerro, stage of glaciation. Uranium-vanadium, manganese, and copper ore as well as gravel have been mined in the Klondike district. All deposits are small, and few have yielded more than 100 tons of ore. Most of the latter are carnotite deposits. Carnotite occurs in the lower

  4. Experiments by the Mexican NNEC on the Control of Airborne Radioactive Contamination; Experiencias Realizadas en la CNEN de Mexico Sobre El Control de Contaminaciones Radiactivas Arrastradas por el Aire

    Energy Technology Data Exchange (ETDEWEB)

    Bravo S, E. [Comision Nacional de Energia Nuclear, Mexico D.F. (Mexico)


    The installations of the Mexican National Nuclear Energy Commission have to deal with the problem of environmental contamination caused by dust and aerosols suspended in the air and originating mainly with such uranium-bearing ores as tyuyamunite, carnotite, betafite, technical-grade sodium uranate, ammonium uranate concentrate, uranium tetrafluoride and uranium dioxide. To prevent environmental contamination by these radioactive materials, the Commission has experimented with three different systems, based on the principle of extracting the dust from the environment, passing it through a cyclone system, separating the particles of larger size and controlling the small particles or aerosols by means of filtration, dilution in liquid columns and dilution in liquid curtains. On the basis of the results obtained, plans have been made for supplementing the systems with an adsorption column and an ion exchange column, depending on the specific requirements of each laboratory. (author) [Spanish] En las instalaciones de la Comision Nacional de Energia Nuclear de Mexico existe el problema de la contaminacion ambiental producida por polvos y aerosoles suspendidos en el aire, de minerales uraniferos tales como tyuyamunita, carnotita, betafita, uranato de sodio tecnico, concentrado de uranato de amonio, tetrafluoruro de uranio y bioxido de uranio fundamentalmente. Para evitar dicha contaminacion del medio ambiente con los materiales radiactivos mencionados, se han experimentado tres diferentes sistemas cuyo principio consiste en la extraccion de los polvos del medio ambiente, pasandolos a un sistema de ciclon, separando las particulas de mayor tamano y controlando las particulas pequenas o aerosoles por medio de filtracion, dilucion en columnas liquidas y dilucion en cortinas liquidas. Sobre la base de los resultados obtenidos se ha proyectado completar los sistemas de acuerdo a las necesidades especificas de cada laboratorio con una columna de adsorcion y otra de intercambio

  5. The geology and geochemistry of some epigenetic uranium deposits near the Swakop River, South West Africa

    International Nuclear Information System (INIS)

    Hambleton-Jones, B.B.


    This study comprises a geological and geochemical investigation of the uranium deposits in the region near the Swakop River which extends from the Langer Heinrich Mountain in the east to the end of the Tumas River in the west. The general geology of the basement rocks in the Langer Heinrich region only is discussed. The general geology of the younger duricrust formations is discussed. Analytical methods were developed for the separation of thorium, protactinium and uranium from geological materials using various chromatographic procedures. Alpha spectrometry, neutron activation analysis and delayed neutron counting were the main techniques used. The occurrence of uranium in the region of study follows a unique geochemical cycle, and the geochemistry at each stage in the cycle was examined. The first stage in the uranium-geochemical cycle was the basement rocks. The second stage in the geochemical cycle of uranium was the subsurface water. The third stage in the geochemical cycle of uranium concerns its occurrence in the duricrust deposits. Isotopic disequilibrium measurements showed that uranium is still migrating, and that the age of the carnotite precipitation is 30 000 years, based on the open-system model of uranium migration. In the final stage of the geochemical cycle, the geochemistry of uranium in seawater and the diatomaceous muds is discussed. A classification system for the uranium deposits near the Swakop River, based on genetic relationships, is proposed and described in terms of the geochemical cycle of uranium, the mode of transport and mode of deposition. The relationships between the duricrust uranium deposits and the other uranium deposits of South Africa are compared

  6. National Uranium Resource Evaluation. Groundwater prospecting for sandstone-type uranium deposits: the merits of mineral-solution equilibria versus single element tracer methods. Final report

    International Nuclear Information System (INIS)

    Chatham, J.R.; Wanty, R.B.; Langmuir, D.


    Groundwaters from aquifers in two different sandstone-type uranium mining districts in Texas and Wyoming were collected and chemically analyzed. The data were used to compare the merits of using the computed saturation state of the groundwater with respect to uranium minerals, to that of single-element tracers in the groundwater for geochemical prospecting. Chemical properties of the Texas waters were influenced locally by preferred groundwater flow within buried fluvial channel deposits; upward leakage of brines along growth faults into the aquifer; and the establishment of a redox interface (Eh = 0 volts) within the aquifer. Chemical characteristics of aquifer waters in Wyoming changed gradually downdip, reflecting regional homogeneity in groundwater flow and a more gradual downdip reduction of Eh values than in Texas. The most reliable indicator of reduced uranium ore in both study sites was the saturation state of groundwater with respect to uraninite or coffinite. For both minerals, this saturation state increased from 15 to 20 log units as reduced ore deposits were approached over distances of 3 to 4.5 km in both sites. Tyuyamunite and carnotite approached or exceeded saturation in some oxidized waters of the Texas site reflecting possible occurrences of these minerals. The radiogenic elements Ta and Rn were excellent indicators of ore directly within the deposits, where anomalous values were 2 to 3 orders of magnitude above background. Helium also increased near the ore, although anomalies were generally displaced in the direction of groundwater flow. Uranium and uranium isotope values did not individually pinpoint ore, but may be used together to classify groundwater samples in terms of their position relative to uranium mineralization

  7. Application of solution-mineral equilibrium chemistry to solution mining of uranium ores

    International Nuclear Information System (INIS)

    Riese, A.C.; Propp, C.J.


    Modern methods of uranium solution mining are typically accompanied by gains and losses of mass through reagent consumption by rock-forming minerals, with subsequent formation of clay minerals, gypsum, carbonates, and iron oxyhydroxides. A systematic approach to alleviate such problems involves the application of leach solutions that are in equilibrium with the host-rock minerals but in disequilibrium with the ore-forming minerals. This partial equilibrium can be approximated by solution-composition adjustments within the systems K 2 O-Al 2 O 3 SiO 2 -H 2 O and Na 2 O 3 -Al 2 O 3 SiO 2 -H 2 O. Uranium ore containing 0.15 percent U 3 O 8 from the Gulf Mineral Resources Corporation's Mariano Lake mine, the Smith Lake district of the Grants mineral belt, was collected for investigation. Presented are a theoretical evaluation of leachate data and an experimental treatment of the ore, which contained mainly K-feldspar, plagioclase feldspar, and quartz (with lesser amounts of micas, clay minerals, and organic carbonaceous material). Small-scale (less than or equal to 1 kg) column-leaching experiments were conducted to model the results of conventional leaching operations and to provide leachate solutions that could be compared with solutions calculated to be in equilibrium with the matrix minerals. Leach solutions employed include: 1) sulfuric acid, 2) sodium bicarbonate, and 3) sulfuric acid with 1.0 molal potassium chloride. The uranium concentrations in the sodium-bicarbonate leach solution and the acid-leach solution were about a gram per liter at the termination of the tests. However, the permeability of the ore in the acid leach was greatly reduced, owing to the formation of clay minerals. Uranium solubility in the leach column stabilized with the potassium-chloride solution was calculated from leachate compositions to be limited by the solubility of carnotite

  8. New Au-U deposit type in the weathering crust in tectonicmetasomatite zones of Pre-Cambrian shields

    International Nuclear Information System (INIS)

    Tarkhanov, A.


    Au-U mineralization is widely distributed in the tectonic-metasomatite zones of Pre-Cambrian shields (Aldan Shield, Ukraine Shield and others). The industrial ores are located only in several areas at depths of more than 150-300 m. Uranium mineralization is represented by uranotitnates and the gold mineralization by auriferous pyrite. The zone of weathering is present to the depth of 100-150 m. The feldspars are replaced by the clay minerals, carbonates are dissovled, sulfides are oxidized and the secondary minerals of uranium replace uranotitanates.The golden mineralization in the envelope of weathering is represented by the fine-grained native gold. The particle size is 40-50 nm. Uranium mineralization is in the form of relict brannerite, tuyamunite, torbernite, carnotite. The gold content is 1-2 g/t, and uranium content 0.01- 0.05% U. Ore bodies of gold and uranium are located inside the tectonic-metasomatite zones. The zones of maximum concentration of these metals may not coincide. The gold ore bodies have the length of hundreds meters and a thickness of 1-5 m. The vertical extent of the secondary Au-U mineralization is 100-150 m. 20 laboratory samples of ore from the weathered zone were tested by the method of heap leaching. The first stage is the uranium leach by diluted sulfuric acid. The second stage is the cyanation of gold and silver. The experimental data indicates leach rate of uranium 75%, gold 80-97%, silver 50-60%. Gold resources in the continous zone is estimated to be 80 t. Gold resources of the several other zones inside the area of 100 km 2 are estimated as 220 t. The heap leach process can be used for profitable development of the low-grade deposits. This method helps to increase the resources of gold and uranium. (author)

  9. Deposit of molybdenum associated with uranium in Pena Blanca, Mexico

    International Nuclear Information System (INIS)

    Reyes-Cortes, M.


    The uranium-molybdenum deposits are in the Sierra Pena Blanca, 45 km north of the city of Chihuahua. The largest amounts of uranium-molybdenum ore are found in the area of Las Margaritas-Puerto III. The ratio of molybdenum mineralization to uranium is 2:1 in this area and the deposits are distributed at depths of 55-100 m in ignimbritic rocks of the so called Escuadra Formation. This volcanic unit consists of an altered crystalline-lithic ash-flow tuff of Oligocene age. The molybdenum mineral occurs as powellite (CaMoO 4 ) and is found predominantly in two size ranges: phenocrysts 0.1-20 mm in diameter are abundant in the upper part of the deposit, while a material which varies between cryptocrystalline and amorphous predominates in the lower part. This latter material can easily be identified inside the mine by its strong orange fluorescence; it is also easy to recover by leaching. In contrast, the metallurgical process of recovery by leaching of the phenocrystalline portion of the powellite has so far presented problems. Powellite is generally found in association with carnotite, margaritasite and uranophane, and its mineralization consists of disseminated lumps, druses, crustifications and veins; frequently, it partially replaces the phenocrysts of argillized feldspars of the Escuadra Formation. Fractured and brecciated zones with intense oxidation of jarosite, haematite, limonite and goethite sometimes show high U-Mo concentrations; on other occasions the concentration is found with alunite at the contact between the ignimbrite and the layers of argillized vitrophyre. The mineralizations of fluorite, pyrite, jarosite, alunite and opal are indicative of hydrothermal deposition, possibly at low temperature with supergene or geothermal alterations. (author)

  10. Uranium exploration in Australia

    International Nuclear Information System (INIS)

    Battey, G.C.; Hawkins, B.W.


    As a result of exploration which recommenced in 1966 Australia's uranium reserves increased from 6,200 tonnes in 1967 to 227,000 tonnes uranium by June 1976. Most discoveries in the early 1950's were made by prospectors. The increase in reserves during the past decade is the result of exploration by companies utilising improved technology in areas selected as geologically favourable. These reserves were established at relatively low cost. In the Alligator Rivers Uranium Province the ''vein'' type deposits at Jabiluka, Ranger, Koongarra and Nabarlek contain 17% of the world's reserves. Most of these discoveries resulted from the investigation of airborne radiometric anomalies but cover over the prospective host rocks will necessitate the future use of costlier and more indirect exploration techniques. There was exploration for sandstone type uranium deposits in most of Australia's sedimentary basins. The greatest success was achieved in the Lake Frome Basin in South Australia. Other deposits were found in the Ngalia and Amadeus Basins in Central Australia and in the Westmoreland area, N.W. Queensland. A major uranium deposit was found in an unusual environment at Yeelirrie, Western Australia where carnotite occurs in a caliche and clay host which fills a shallow, ancient drainage channel. Although caliche occurrences are relatively widespread on the Precambrian shield no other economic deposit has been found. Recent discoveries in the Georgetown area of Queensland indicate the presence of another uranium province but it is too early to assess its potential. The ore occurs in clastic sediments at the base of a volcanic sequence overlying a Precambrian basement. Several companies which have established large uranium reserves have a number of additional attractive prospects. Exploration activity in Australia in 1975 was at a lower level than in previous years, but the potential for discovering further deposits is considered to be high

  11. Depletion of energy or depletion of knowledge alternative use of energy resources

    International Nuclear Information System (INIS)

    Arslan, M.


    This research paper is about the depletion of Energy resources being a huge problem facing the world at this time. As available energy sources are coming to a shortage and measures are be taken in order to conserve the irreplaceable energy resources that leads to sustainability and fair use of energy sources for future generations. Alternative energy sources are being sought; however no other energy source is able to provide even a fraction of energy as that of fossil fuels. Use of the alternative energy resources like wind corridors (Sindh and Baluchistan), fair use of Hydro energy (past monsoon flooding can produce enough energy that may available for next century). Uranium Resources which are enough for centuries energy production in Pakistan (Dhok Pathan Formation) lying in Siwalick series from Pliocene to Pleistocene. Among all of these, my focus is about energy from mineral fuels like Uranium from Sandstone hosted deposits in Pakistan (Siwalik Series in Pakistan). A number of uranium bearing mineralized horizons are present in the upper part of the Dhok Pathan Formation. These horizons have secondary uranium mineral carnotite and other ores. Uranium mineralization is widely distributed throughout the Siwaliks The purpose of this paper was to introduce the use of alternative energy sources in Pakistan which are present in enough amounts by nature. Pakistan is blessed with wealth of natural resources. Unfortunately, Pakistan is totally depending on non renewable energy resource. There are three main types of fossil fuels: coal, oil and natural gas. After food, fossil fuel is humanity's most important source of energy. Pakistan is among the most gas dependent economies of the world. Use of fossil fuel for energy will not only increase the demand of more fossils but it has also extreme effects on climate as well as direct and indirect effects to humans. These entire remedial thinking can only be possible if you try to use alternative energy resources rather than

  12. Evaluation of systems incorporating transmutation for the reduction of the long term toxicity of high-level waste

    International Nuclear Information System (INIS)

    Davidson, J.W.


    One of the alternative high-level nuclear waste (HLW) management/disposal concepts proposed involves the separation from HLW of the elements with isotopes which dominate the radiotoxicity and the transmutation of these nuclides to shortlived or stable products. The waste management system required for transmutation employs chemical processing of HLW to recover waste nuclides for irradiation with neutrons in a transmutation device. The transmuter periodically requires replenishment of the target nuclides and chemical processing to remove the transmutation products. The waste streams from HLW processing and product recovery together comprise the discharge from the system. An imploding liner fusion reactor (ILFR) is assumed for the transmuter with the waste nuclides dissolved in a molten lead-lithium alloy blanket. The potential transmutation candidates are defined as the elements with toxicities per unit volume (toxicity indexes) in solidified HLW at 1000 years which are greater than that for 0.2% uranium ore (carnotite). The candidates which require separation for transmutation are the actinides; Np, Pu, Am, and Cu and the fission products; I and Tc. Certain assumptions were made for the parameters for the ILFR and its operating conditions, and a system evaluation was done. System evaluations indicate that blanket waste loadings on the order of several percent of the total concentration result in attractive performance in terms of high transmutation capacities and low blanket processing requirments. It appears that transmutation system goals in terms of toxicity reduction are achievable with a modest number of transmuters. In addition, requirements for transmuter performance, chemical processing capacity and chemical separation efficiency appear to be within projected values for this technology

  13. Virgin Valley opal district, Humboldt County, Nevada (United States)

    Staatz, Mortimer Hay; Bauer, Herman L.


    The Virgin Valley opal district, Humboldt County, Nevada, is near the Oregon-Nevada border in the Sheldon Game Refuge. Nineteen claims owned by Jack and Toni Crane were examined, sampled, and tested radiometrically for uranium. Numerous discontinuous layers of opal are interbedded with a gently-dipping series of vitric tuff and ash which is at least 300 ft thick. The tuff and ash are capped by a dark, vesicular basalt in the eastern part of the area and by a thin layer of terrace qravels in the area along the west side of Virgin Valley. Silicification of the ash and tuff has produced a rock that ranges from partly opalized rock that resembles silicified shale to completely altered rock that is entirely translucent, and consists of massive, brown and pale-green opal. Carnotite, the only identified uranium mineral, occurs as fracture coatings or fine layers in the opal; in places, no uranium minerals are visible in the radioactive opal. The opal layers are irregular in extent and thickness. The exposed length of the layers ranges from 8 to 1, 200 ft or more, and the thickness of the layers ranges from 0. 1 to 3. 9 ft. The uranium content of each opal layer, and of different parts of the same layer, differs widely. On the east side of Virgin Valley four of the seven observed opal layers, nos. 3, 4, 5, and 7, are more radioactive than the average; and the uranium content ranges from 0. 002 to 0. 12 percent. Two samples, taken 5 ft apart across opal layer no. 7, contained 0. 003 and 0. -049 percent uranium. On the west side of the valley only four of the fifteen observed opal layers, nos; 9, , 10, 14, and 15, are more radioactive than the average; and the uranium content ranges from 0. 004 to 0. 047 percent. Material of the highest grade was found in a small discontinuous layer of pale-green opal (no. 4) on the east side of Virgin Valley. The grade of this layer ranged from 0. 027 to 0. 12 percent uranium.

  14. Identification of Uranium Minerals in Natural U-Bearing Rocks Using Infrared Reflectance Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Beiswenger, Toya N. [Pacific Northwest National Laboratory, Richland, WA, USA; Gallagher, Neal B. [Eigenvector Research, Inc., Manson, WA, USA; Myers, Tanya L. [Pacific Northwest National Laboratory, Richland, WA, USA; Szecsody, James E. [Pacific Northwest National Laboratory, Richland, WA, USA; Tonkyn, Russell G. [Pacific Northwest National Laboratory, Richland, WA, USA; Su, Yin-Fong [Pacific Northwest National Laboratory, Richland, WA, USA; Sweet, Lucas E. [Pacific Northwest National Laboratory, Richland, WA, USA; Lewallen, Tricia A. [Pacific Northwest National Laboratory, Richland, WA, USA; Johnson, Timothy J. [Pacific Northwest National Laboratory, Richland, WA, USA


    The identification of minerals, including uranium-bearing minerals, is traditionally a labor-intensive-process using x-ray diffraction (XRD), fluorescence, or other solid-phase and wet chemical techniques. While handheld XRD and fluorescence instruments can aid in field identification, handheld infrared reflectance spectrometers can also be used in industrial or field environments, with rapid, non-destructive identification possible via spectral analysis of the solid’s reflectance spectrum. We have recently developed standard laboratory measurement methods for the infrared (IR) reflectance of solids and have investigated using these techniques for the identification of uranium-bearing minerals, using XRD methods for ground-truth. Due to the rich colors of such species, including distinctive spectroscopic signatures in the infrared, identification is facile and specific, both for samples that are pure or are partially composed of uranium (e.g. boltwoodite, schoepite, tyuyamunite, carnotite, etc.) or non-uranium minerals. The method can be used to detect not only pure and partial minerals, but is quite sensitive to chemical change such as hydration (e.g. schoepite). We have further applied statistical methods, in particular classical least squares (CLS) and multivariate curve resolution (MCR) for discrimination of such uranium minerals and two uranium pure chemicals (U3O8 and UO2) against common background materials (e.g. silica sand, asphalt, calcite, K-feldspar) with good success. Each mineral contains unique infrared spectral features; some of the IR features are similar or common to entire classes of minerals, typically arising from similar chemical moieties or functional groups in the minerals: phosphates, sulfates, carbonates, etc. These characteristic 2 infrared bands generate the unique (or class-specific) bands that distinguish the mineral from the interferents or backgrounds. We have observed several cases where the chemical moieties that provide the

  15. IAEA sends out samples of uranium ore

    Energy Technology Data Exchange (ETDEWEB)



    Full text: Governments and organizations interested in developing uranium resources will be assisted by a new service, now being inaugurated by the Agency's laboratories, for the distribution of reference samples of uranium ores. This is an addition to the service which began at Seibersdorf in January 1962 for the distribution of calibrated radionuclides, and which has met with a steadily increasing demand. * Uranium deposits consisting of ores with a uranium content in the range 0.5 - 0.05 per cent occur in a number of countries, including developing countries and can present considerable analytical difficulties. In 1962 the Agency asked Member States whether they would be interested in receiving reference samples of uranium ores to assist them in checking their methods of chemical analysis. The response encouraged the Agency to proceed. There is a multiplicity of types of uranium ores and, initially, three of the most commonly occurring have been selected - torbernite, uraninite and carnotite. Member States have provided the laboratory with supplies of these three types of ore. In order to determine the uranium content, samples are sent to leading laboratories throughout the world, so as to arrive at the most accurate values possible. This work has proved to be useful to the laboratories themselves ; in searching for reasons for discrepancies between the different collaborating laboratories, they enlarge their own knowledge and improve their methods. The reference samples are sent out in the form of fine powder, and are available to atomic energy commissions, research laboratories or mining companies. The requesting laboratory, having worked out the analytical process best suited to its needs, is then able to check its results by analysing an IAEA reference sample of known uranium content. By the end of 1966, reference samples will be available of the three ores mentioned, and later also of pure uranium oxide and of uranium oxide containing trace impurities, the