Uranium resources

Uranium resources were originally expected to be rapidly depleted in a growing economy. There were, however, ample suppHes of uranium as of... 

The U.S. Department of Energy (DOE) and the NEA/IAEA employ similar terms to classify uranium resources, as (7) reasonably assured, estimated additional (EA), or speculative. The NEA/IAEA divides the estimated additional resources into two types, EAR-I and EAR-II, describing known resources and undiscovered ones, respectively (8). 

Lignite. Deposits generally classified as unconventional uranium resources occur in lignite and in clay or sandstone immediately adjacent to lignite. Examples are uraniferous deposits in the Serres Basin, Greece, North and South Dakota in the United States, and Melovoe in the CIS (17) (see... 

Domestic. Estimates of U.S. uranium resources for reasonably assured resources, estimated additional resources, and speculative resources at costs of 80, 130, and 260/kg of uranium are given in Table 1 (18). These estimates include only conventional uranium resources, which principally include sandstone deposits of the Colorado Plateaus, the Wyoming basins, and the Gulf Coastal Plain of Texas. Marine phosphorite deposits in central Elorida, the western United States, and other areas contain low grade uranium having 30—150 ppm U that can be recovered as a by-product from wet-process phosphoric acid. Because of relatively low uranium prices, on the order of 20.67/kg U (19), in situ leach and by-product plants accounted for 76% of total uranium production in 1992 (20). 

Foreign. The OECD/NEA and IAEA have issued annual reports on world uranium resources, production, and demand since the mid-1960s (2—6). NEA/IAEA data for reasonably assured and estimated additional resources at costs of 80 and 130/kg uranium are given in Table 2 (21). These estimates incorporate data from both former world outside centrally planned economies (WOCA) and non-WOCA nations. A summary of other known uranium resources with and without cost range estimates is provided in Table 3 (22). These resources total about 1.4 x 10 t and include estimates that are not strictly consistent with standard NEA/IAEA definitions. 

Estimates of speculative lesouices (SR) at 130/kg uianium and those having an unassigned cost range are provided ia Table 4 (23). These resources, which total about 11.28 x 10 t, would be ia addition to the reasonably assured and estimated additional resources. Estimates of uranium resources from unconventional and by-product sources are presented ia Table 5 (24). These resources total about 7 x 10 t for phosphates, 0.013 x 10 t for nonferrous ores, 0.016 x 10 t for carbonates, and 0.014 x 10 t for lignites. These would be ia addition to the reasonably assured resources, estimated additional resources, and the speculative resources (24). 

Resource estimates are divided into separate categories reflecting different levels of confidence in the quantities reported, and further separated into categories based on the cost of production. A listing of uranium resources by country is given in Table 3. 

For example, the measure of change fix>m coal to natural gas or nuclear fuel is classified itrto regrettable one from the viewpoints of resources, because the amount of natural gas or uranium resources is much less than that of coal. 

Table 1.18 Major uranium resources of the world numbered in sequence on the basis of their geological setting and arranged according to their approximate economic significance.

Depending upon lithologic and structural relationship with host rocks, mineralogy, attendant alteration, paragenesis and spatial and temporal constraints, the uranium resources of the world can be assigned to the 15 main categories of uranium ore deposits. They have been shown numerically numbered in sequence in the order of their approximate economic significance in Table 1.18. At present, only 7 can be said to be economically important (see Table 1.19) and these account for more than 95% of the world resources of ura-... 

Figure 1.23 Uranium resources -Distribution in major types of deposits.

Figure 1.24 Uranium resources -Country-wide distribution (WOCA Countries).

Uranium, Resources, Production and Demand, A Joint Report by the OECD-NEA and IAEA, 1993. 

C. K. Gupta and H. Singh, Uranium Resource Processing - Secondary Resources, under publication by Springer-Verlag, Berlin, Heidelberg, New York, Germany. 

Data on the geographic distribution of surficial radium concentrations were acquired by the National Airborne Radiometric Reconnaissance (NARR) survey, part of the National Uranium Resource Evaluation (NURE) program conducted by the U.S. Department of Energy in the mid-1970s. The data were originally collected and tabulated by 1° by 2° quadrangle map area, and the data cover approximately 450 out of a total of 474 such quadrangles... 

National Uranium Resource Evaluation (NURE) Hydrochemical and Stream Sediment Reconnaissance (HSSR) Program. U.S. Geological Survey Open-File Report 97-492. Available from . 

Bolivar, S.L. 1980. An overview of the National Uranium Resource Evaluation Hydrogeochemical and Stream sediment Reconnaissance Program. Los Alamos Scientific Laboratory. LA-8457-MS, 24 p. 

Foreign uranium resources, 17 522 Foreman and Veatch cell, 9 664 Forensic analysts, certification of, 12 95 Forensic biology, 12 102-104 Forensic chemistry, 12 89-104 physical evidence in, 12 90-95 Forensic laboratories, local and state, 12 98 Forensics, liquid chromatography applications, 6 465 Forensic science laboratories, 12 95 Forensic science, supercritical fluid extraction in, 24 14 Forensic testing, 12 95-104 Forensic toxicology, interpretation of results in, 12 98... 

Uranium refining, 25 404—405 Uranium reserves, 17 521-522 Uranium resources, 17 522-525,... 

Resource category Extraction cost ranges ( /kg U) Uranium resources (kt) Individual Total Data reliability... 

Figure 4.5 illustrates the distribution of uranium resources among the ten major countries. Approximately 90% of the resources in all RAR and IR categories are to be found in those ten countries, with the leading ones being Australia, Kazakhstan, Canada and South Africa. 

Figure 4.5. Top ten countries uranium resources in 2003 (NEA/IAEA, 2006a).

Besides the conventional uranium resources, there are also the so-called unconventional uranium resources , which are defined as deposits with very low uranium content, from which uranium is typically only recoverable as a minor by-product. These unconventional uranium resources are obtained from the extraction of phosphates, non-ferrous ores and carbonatites, as well as black schist and lignite. It has to be noted that the distinction between conventional and unconventional resources is not entirely clear cut, but is, instead, somewhat transitional. 

Another potentially vast resource is seawater. Uranium resources associated with the oceans are estimated at around 4000 million tonnes however, the uranium concentration in seawater is only around 0.003 ppm. The recovery of uranium from seawater is still subject to basic research. Considerable technological developments as well as significant improvements of economics (or drastic increases in uranium prices) are crucial for the commercial use of this resource, which is unlikely in the foreseeable future. As the energy demand for uranium extraction increases with lower concentrations, the net energy balance of the entire fuel cycle is also critical. 

The development of thorium-based nuclear power cycles still faces various problems and requires much more R D to be commercialised. As a nuclear fuel, thorium could play a more important role in the coming decades, partly as it is more abundant on Earth than uranium and also because mined thorium has the potential to be used completely in nuclear reactors, compared with the 0.7% of natural uranium. Its future use as a nuclear source of energy will, however, depend greatly on the technological developments currently investigated in various parts of the world and the availability of and access to conventional uranium resources. 

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