Uranium exploration

Keywords Biogeochemistry, Exploration, Uranium, Base Metals, Molybdenum... 

Today s bismuth situation looks like uranium one during the period from 1906 to 1940 when only 40001 of uranium were mined over the 34 years. But in 1980 the world s uranium mining (except the ex-USSR) reached 400001 per year [18]. The explored uranium resources increased greatly too. 

Once all technical and pohtical problems are resolved, reactor-grade uranium produced from HEU warhead material could contribute significantly to meeting the anticipated fresh uranium production shortfall. This source, however, is not expected to have a significant impact until the year 2000 or later. The discovery of new low cost resources is not expected to make a significant contribution to production until after the year 2005 because of the very low level of uranium exploration and the relatively long lead times required to develop new production centers (29). 

Uranium is used as the primai-y source of nuclear energy in a nuclear reactor, although one-third to one-half of the power will be produced from plutonium before the power plant is refueled. Plutonium is created during the uranium fission cycle, and after being created will also fission, contributing heat to make steam in the nuclear power plant. These two nuclear fuels are discussed separately in order to explore their similarities and differences. Mixed oxide fuel, a combination of uranium and recovered plutonium, also has limited application in nuclear fuel, and will be briefly discussed. 

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. 

Gueniot B, Munier-Lamy C, Berthelin J (1988b) Geochemical behavior of Uranium in soils, part 11 Distribution of uranium in hydromorphic soils and soil sequences. Application for suificial prospecting. J Geochem Explor 31 39-55... 

P. R. Simpson, eds., in Uranium Geochemistry, Mineralogy, Geology, Exploration and Resources, IMM, London, p. 43,1984. 

Card, J.W, and K. Bell, Radon Decay Products and their Application to Uranium Exploration, CIM Bull., 72 81-87 (1979). 

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

The characteristic feature of the uranium exploration industry is the radioactivity of all wastes. The quality of these wastes, such as radon, radioactive aerosols, and dust emitted to the atmosphere, depends on mine production and the radioactive budget in the mines. For example, middle range mine exploring the ores with n x 10 1-10 2% of U content emits to the atmosphere up to 8 x 1010 Bq/day of radon. 

The amount of solid waste depends on the method of uranium ore exploration. By deep mining, each ton of ore is supplemented by 0.2-0.3 tons of waste ores, and by open pit mining, per 1 ton of ore up to 8-10 tons of excavation materials are produced. Moreover, uranium ores contain from 5% up to 25-30% of waste ores, which are deposited as mine tails. 

The relative area of mine solid waste tails (per 100,000 M3 of rock mass) is 0.7-0.8 of the total area. On average, the disturbed areas of uranium ore exploration site are partitioned as follows 32.3% of disturbed land is occupied by dumps, 27.2%, by pits, 20.3%, by industrial areas, 13.3%, by tails, and about 10%, by other types of land disturbance. 

The further transformation of uranium exploration areas depends on the landscape biogeochemical conditions. Let us consider two examples of different conditions, dry steppe and permafrost taiga regions (Perelman, Kasimov, 1999). 

Apatite exploration takes place in various regions of the World, and the most known are Kola Peninsula (Russia) and northwest Africa (Morocco). In both places, the apatite ores contain not only phosphorus as a main element but also many heavy metals, which are toxic for humans and animals. The given elements are F, As, Y, some rare earth species, Sr, Pb, Cd, Sn. The underground waters in these regions are enriched by F, Fi, Nb, some rare earth species with alkaline reaction that facilitates the migration of many ore elements. Some phosphorus containing ores are radioactive owing to the mixtures of uranium and thorium. 

Uranium carbonates, 25 430-432 Uranium chlorides, 25 438-439 Uranium compounds, 25 421-434 handling, 17 529 Uranium dioxide, 25 422-423 Uranium-enrichment process gas centrifuge, 25 413-415 Uranium exploration, 25 398 URanium Extraction (UREX) process, 25 420... 

At Los Alamos National Laboratory in New Mexico the Analytical Chemistry Group (C-AAC) supports the Pu-238 Heat Source Project that fabricates heat sources for use in the space industry. These heat sources have been used on NASA s deep-space probes and on instruments exploring the surface of Mars. The chemical and isotopic purity of the heat sources are critically controlled to ensure dependable service. The Radiochemistry Task Area performs analyses of the heat source material for four radioisotopes americium-241, plutonium-238, neptunium-237, and uranium-235. 

In summary, the development of inorganic membranes was initially oriented towards uranium enrichment which is still by very far their most significant application. Some of the key participants involved in the nuclear programs further developed them into cross-flow filtration membranes. The recent years have seen the start of a much broader exploration of the manyfold potentialities of inorganic membranes, both in terms of materials and applications. Thus, a multifaceted new field of technology is emerging. 

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