Uranium deposition

Originally, radium was obtained from the rich pitchblende ore found in Joachimsthal, Bohemia. The carnotite sands of Colorado furnish some radium, but richer ores are found in the Republic of Zaire and the Great Lake region of Canada. Radium is present in all uranium minerals, and could be extracted, if desired, from the extensive wastes of uranium processing. Large uranium deposits are located in Ontario, New Mexico, Utah, Australia, and elsewhere. 

Geochemical Nature and Types of Deposits. The cmst of the earth contains approximately 2—3 ppm uranium. AlkaHc igneous rock tends to be more uraniferous than basic and ferromagnesian igneous rocks (10). Elemental uranium oxidizes readily. The solubiHty and distribution of uranium in rocks and ore deposits depend primarily on valence state. The hexavalent uranium ion is highly soluble, the tetravalent ion relatively insoluble. Uraninite, the most common mineral in uranium deposits, contains the tetravalent ion (II). 

Volcanic Deposits. Uranium deposits of volcanic deposits type are strata-bound and stmcture-bound concentrations in acid volcanic rocks. Uranium is commonly associated with molybdenum, fluorine, etc. Examples are the uranium deposits in Michelin, Canada Nopal I in Chihualiua, Mexico Macusani in Pern and numerous deposits in China and the CIS (16). 

Sur cia.1 Deposits. Uraniferous surficial deposits maybe broadly defined as uraniferous sediments, usually of Tertiary to recent age which have not been subjected to deep burial and may or may not have been calcified to some degree. The uranium deposits associated with calcrete, which occur in Australia, Namibia, and Somaha in semiarid areas where water movement is chiefly subterranean, are included in this type. Additional environments for uranium deposition include peat and bog, karst caverns, as well as pedogenic and stmctural fills (15). 

Meta.soina.tlte Deposits. Included in the metasomatite deposit grouping are uranium deposits in alkah metasomatites, eg, albitites, aegirinites, and alkah—amphibole rocks, commonly intmded by microcline granite. Examples are the deposits in Espinharasin, Brazil, and Ross Adams, Alaska, as well as the Zheltye Vody deposit in Krivoy Rog area in Ukraine (16). 

MetamorphicDeposits. Uranium deposits belonging to the metamorphic class occur in metasediments or metavolcanics generally, without direct evidence of post-metamorphic mineralization. Examples include the deposits at Eorstau, Austria (16). 

Other Deposits. Those deposits which cannot be classified as one of the previous 14 deposit types are called other. These include the uranium deposits in the Jurassic Todilto Limestone in the Grants district in New Mexico (17). 

Studies show that the main sites of uranium deposition ate the renal cortex and the Hvet (8). Uranium is also stored in bones deposition in soft tissues is almost negligible. Utanium(VI) is deposited mostly in the kidneys and eliminated with the urine whereas, tetravalent uranium is preferentially deposited in the Hvet and eliminated in the feces. The elimination of uranium absorbed into the blood occurs via the kidneys in urine, and most, - 84%, of it is cleared within 4 to 24 hours (8). 

Uranium is found in most rock, in a concentration of two to four parts per million (ppm). Substantially greater average concentrations can be found in mineral deposits, as high as 10,000 ppm, or 10 percent. Most uranium deposits suitable for mining, however, contain an average of less than 1 percent uranium. Uranium is a metal, and thus its acquisition is not unlike the mining of any other metallic ore. Although uranium is found nearly eveiywhere on the earth, Canada leads the world in uranium production, mostly due to its heavy financial investment m uranium exploration, and to a few sizable deposits in the Saskatchewan territoiy. Table 1 depicts the total world uranium production in 1997. 

It may seem unlikely that all these conditions could have been met, but at least one deposit of uranium ore has characteristics indicating that, long ago, it operated as a natural nuclear reactor. At Oklo in the Gabon Republic near the western coast of equatorial Africa (see photo), there are uranium deposits of high purity... 

Total exposures vary considerably with human activities as well. Frequent flyers, for example, receive higher doses of radiation because the intensity of cosmic radiation is significantly greater at high altitude than it is at ground level. Residents in locations such as Montana and Idaho, where there are uranium deposits, receive higher doses of radiation from radon, one of the radioactive decay products of uranium. 

C22-0081. Uranium deposits are dated by determining the ratio of U to its final decay product,... 

Payne XE, Edis R, Fenton BR, Waite XD (2001) Comparison of laboratory nraninm sorption data with in situ distribution coefficients at the Koongarra uranium deposit. Northern Australia. J Environ Radioact 57 35-55... 

Palaeoplacers are placer concentrations that have occurred in the geological past and which are preserved till the present by a cover of later sedimentary rocks. The Witwatersrand gold-uranium deposits (South Africa) and the uranium deposits at Blind River (Ontario, Canada) and Jacobina (Brazil) are the most important examples of palaeoplacers. 

By far the most important ores of iron come from Precambrian banded iron formations (BIF), which are essentially chemical sediments of alternating siliceous and iron-rich bands. The most notable occurrences are those at Hamersley in Australia, Lake Superior in USA and Canada, Transvaal in South Africa, and Bihar and Karnataka in India. The important manganese deposits of the world are associated with sedimentary deposits the manganese nodules on the ocean floor are also chemically precipitated from solutions. Phosphorites, the main source of phosphates, are special types of sedimentary deposits formed under marine conditions. Bedded iron sulfide deposits are formed by sulfate reducing bacteria in sedimentary environments. Similarly uranium-vanadium in sandstone-type uranium deposits and stratiform lead and zinc concentrations associated with carbonate rocks owe their origin to syngenetic chemical precipitation. 

The geological term, uranium occurrence, implies a naturally occurring anomalous concentration of uranium. The term, uranium deposit, implies a mass of naturally occurring mineral material from which uranium could be exploited at present or in the future. An often-encountered term in uranium mineralogy is uranium ore mineral. It is a mineral having such physical and chemical properties and occurring in a deposit in such concentra-... 

R. W. Boyle, Geochemical Prospecting for Thorium and Uranium Deposits, p. 498, Elsevier, New York,... 

Fig. 3. Dissolved uranium at Honeymoon Well. The Centripede Palaeochannel uranium deposit is clearly deliniated.

Ruhrmann, G. von Pechmann, E. 1989. Structural and hydrothermal modification of the Gaertner uranium deposit, Key Lake, Saskatchewan, Canada. IAEA TECDOC-500, 363-377. 

KEYWORDS Unconformity Hosted Uranium Deposit, Nunavut, Geochemistry, Uranium Exploration, Oxygen Stable Isotopes... 

The Lac Cinquante unconformity associated uranium deposit is located in the Kivalliq district of Nunavut approximately 350 km west of Rankin Inlet, and is centered on approximately Latitude 62° 34 33 N, Longitude... 

Regional Geology The Lac Cinquante uranium deposit is located in the Kivalliq Region of the Hearne Subprovince in the Western Churchill Province, Nunavut. The Western... 

Miller, A.R., Stanton, R.A., Cluff, G.R., Male, M.J., 1986. Uranium deposits and prospects of the Baker Lake Basin and subbasins Central District of Keewatin, Northwest Territories. In Evans, E.L. (Ed.) Uranium Deposits of Canada. Canadian Institute of Mining and Metallurgy, Special Volume 33, 263-285. 

Breathing zone measurements, 14 214, 217 Breccia complex uranium deposits, 17 520 Breeding gain (BG), 17 586 Breeding programs, to enhance allelopathy, 13 353... 

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