Uranium Mining in Virginia Scientific, Technical, Environmental, Human Health and Safety, and Regulatory Aspects of Uranium Mining and Processing in Virginia (2012) / Chapter Skim
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3 Uranium Occurrences, Resources, and Markets
3 Uranium Occurrences, Resources, and Markets
Pages 54-95
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From page 54... ...
uranium mining/processing technique. • In 2008, uranium was produced in 20 countries; however, more than 92 percent of the world's uranium production came from only eight countries.
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has classified uranium resources -- on the basis of their geological setting and morphology -- into a num ber of ore deposit types (IAEA, 2009)
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, al though many of the hundreds of uranium-bearing minerals are rarely encountered mineral "curiosities." Among the tetravalent uranium minerals, the two principal ones occurring in ore deposits are uraninite, with a UO2+x composition (called pitchblende when occurring with a colloform texture) , and coffinite (USiO4)
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. Aqueous Geochemistry of Uranium Uraninite and most other common uranium minerals are only sparingly soluble in water at neutral pH, low temperatures, and reducing conditions.
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58 URANIUM MINING IN VIRGINIA BOX 3.1 Continued (A) UO2OH+ Soddyite 1 [(UO2)
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Three main types of magmas can be enriched in uranium: PAl: peraluminous magmas resulting from the partial melting of sedimentary rocks (PAl) ; highly potassic calc-alkaline magmas resulting from the partial melting of a mantle contaminated by subducted sediments (HKCa)
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Uranium minerals impregnate the sandstone matrix within tabular, irregularly shaped, lenticular masses within reduced sediments.
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Hematite Breccia Complex Deposits These deposits occur in hematite-rich breccias, where the uranium minerals are associated with copper, gold, silver, and rare earths. The only representative of this type of deposit presently being mined is Olympic Dam in South Australia.
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Individual deposits contain from a few hundreds of tonnes to 80,000 tonnes of uranium at grades of 0.08 percent to 0.3 percent. Examples include the Michurinskoye and Zheltorechenskoye deposits in Ukraine, and Lagoa Real and Itataia in Brazil.
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Phosphorite deposits constitute large uranium resources, but at a very low grade. Individual deposits contain from tens of thousands of tonnes to more than 3 million tonnes of uranium at grades of 0.01 percent to 0.03 percent.
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From page 64... ...
However, this definition may evolve depending on uranium prices and technological improvements, and some of these resources -- such ura nium in black shales or phosphorites -- may become a significant resource in the future. Other major nonconventional resources are the following: • Several projects are being developed (many in South Africa, and also in the Czech Republic, Kyrgyzstan, and Tajikistan)
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From page 65... ...
One disadvantage of the IAEA classification is that deposits resulting from very different genetic processes and occurring in very different geological environments can end up being grouped in the same category, and this is especially true for vein deposits and uranium deposits disseminated in plutonic rocks. In the case of plutonic rocks, this category contains deposits resulting from partial melting in deep structural settings within high grade metamorphic rocks (e.g., the alaskite dykes of Rössing, in Namibia)
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; deposits resulting from uranium concentration occurring simultaneously with deposi
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VIRGINIA OCCURRENCES AND PROSPECTIVITY STATUS Lassetter (2010) recently presented a compilation of uranium occurrences in the Commonwealth of Virginia, using published reports, unpublished geochemi cal data, and field scintillometer measurements, and this compilation forms much of the basis for this section.
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. That same year, the Virginia legislature instituted a statewide moratorium on uranium mining but left available the right to explore for uranium.
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. These occur in Virginia in three different geological situations and ages -- Middle to Late Proterozoic granites, Late Paleozoic granitic rocks and pegmatites, and Late Jurassic–Early Cretaceous peralkaline intrusive rocks (Lassetter, 2010)
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. FIGURE 3.6 Distribution of Middle to Late Proterozoic granites and gneisses of the Blue Ridge belt, together with complexly deformed mylonites, shear zones, and cataclasites.
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71 URANIUM OCCURRENCES, RESOURCES, AND MARKETS FIGURE 3.7 Uranium/thorium occurrences (green triangles) and radiometric anomalies (red triangles)
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Deposits expected in this geological environment would be Type 1 (fractional crystallization) or Type 3B FIGURE 3.8 Distribution of Late Paleozoic fractionated granitic rocks and pegmatites.
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Synsedimentary Deposits These types of deposits include Devonian-Mississippian sedimentary deposits in the Appalachian Plateau area of western Virginia and marine phos phorites occurring in the Coastal Plain. Devonian-Mississippian Sediments The Devonian-Mississippian black shales (synsedimentary redox trapping; Type 7B)
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Comparable uranium deposits. The Cambrian-Ordovician alum shales in southern Sweden represent uranium resources of over 1 million tU, and the Ranstad deposit alone -- extending over 490 km2 -- contains ~254,000 tU at 170 to 250 ppm.
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If uranium production from phosphorites becomes economically attractive, production would start first in Morocco because of the high uranium grades, and the next most economically attractive would be the Florida deposits. Production of uranium from Virginia phosphorites is not expected in the foresee able future.
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Uranium extraction as a byproduct of REE and thorium recovery from monazite can be expected in the future. However, the extraction of these ele ments will not be the leading factor for increasing the mining of heavy mineral sands; these driving factors are first titanium and zirconium extraction, and then the REEs, and in last position, thorium.
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From page 77... ...
shows an area of elevated uranium levels extending through Somerset and Barboursville, between Hardwick and Cowherd mountains. Uranium levels up to six times the regional average that were found in this area attracted exploration activity, and before the moratorium on uranium mining was enacted, some 2,000 acres in Orange County was under lease to uranium exploration companies.
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The Coles Hill deposit, located in the Pittsylvania County, occurs within a fault-bounded wedge of the sheared and highly potassic calcalkaline Leatherwood Granite (Figures 3.13, 3.14) , along the Chatham Fault Zone at the northwest margin of the Triassic age Danville Basin (Jerden, 2001)
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79 URANIUM OCCURRENCES, RESOURCES, AND MARKETS FIGURE 3.13 Geological map and cross section of the Coles Hill region in Pittsylvania County showing the location of the Coles Hill deposit hosted by deformed granitic rocks (augen gneisses and mylonites) of the Leatherwood Granite, west of the Chatham Fault Zone and underlying the Danville Triassic Basin.
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The Coles Hill deposit contains significant uranium resources at grades comparable to average grades for uranium deposits worldwide, and the main uranium-bearing minerals are easily leachable in acidic or alkaline solutions. Resource calculations for this deposit are shown in Table 3.2.
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. URANIUM RESOURCES, RESERVES, AND MARKETS The global uranium market and uranium prices reflect the fluctuating balance between the demand for uranium for nuclear power generation, and the production from mining/processing and from additional sources such as recycling spent fuel and reprocessing highly enriched uranium and plutonium from decom
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From page 82... ...
domestic uranium mining industry only produced 1,660 metric tonnes (tU) of the 18,376 tU needed to operate the 104 nuclear power plants across the nation, amounting to a domestic deficit of approximately 16,716 tU (~90 percent deficit)
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From page 83... ...
for worldwide uranium resources in a range of resource categories for different cost ranges is presented in Table 3.3, and the RARs in the United States are shown in Table 3.4. For RAR, WNA estimated that the nuclear energy's fuel supply infrastructure should be able to meet world demand in the short term, but expansion will be needed across the entire fuel cycle beyond 2020 (Figure 3.18)
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no clear where the primary production is copper from a hydrothermal orebody, with subsidiary production of uranium, gold, and silver. The dominating effect of the Olympic Dam and other Australian uranium resources are also reflected in RAR comparisons (Figure 3.19)
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, but a large part correspond to the huge Olympic Dam deposit where uranium production is relatively small (about 4,000 tU) because it is tied to the production of copper and gold.
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86 TABLE 3.3 Worldwide Uranium Resource Quantities for Different Production Cost Ranges and Different Degrees of Confidence, as of January 2009 Identified Resources (RAR + Inferred Resources) Reasonably Assured Resources Inferred Resources Cost short tons tonnes short tons tonnes short tons tonnes <$18/lb U <$40/kg U 877,881 796,400 628,207 569,900 249,784 226,600 <$36/lb U <$80/kg U 4,124,739 3,741,900 2,773,525 2,516,100 1,351,213 1,225,800 <$59/lb U <$130/kg U 5,956,890 5,404,000 3,885,537 3,524,900 2,071,353 1,879,100 <$118/lb U <$260/kg U 6,951,506 6,306,300 4,414,206 4,004,500 2,537,300 2,301,800 SOURCE: NEA/IAEA (2010)
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. fivefold increase in uranium production from the Olympic Dam deposit will require an investment of about 15 billion Australian dollars.
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and < $130/kg (< $130/lb) cost points for the 12 major uranium mining countries (in tonnes)
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. This problem is particularly sensitive at present because of several issues: After nearly 20 years of extremely low exploration rates all over the world and with widespread exploration only restarting since 2004, a new generation of geologists specializing in uranium exploration, as well as mining and metallurgical engineers specializing in uranium processing, will need to be educated; and tighter regulations for uranium mining have considerably increased the duration for the licensing of the new uranium mines.
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In the United States, uranium was produced at six locations in the third quarter of 2011. White Mesa Mill, near Blanding, Utah, is the only conventional uranium processing facility currently operating in the United States, processing FIGURE 3.20 Production of uranium worldwide in metric tonnes and short tons from 1999 to 2009.
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750 750 750 750 712 769 750 827 Malawi -- -- -- -- -- -- 104 670 South Africa 758 755 674 534 539 655 563 583 India (est) 230 230 230 177 270 271 290 400 Czech Repub.
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From page 92... ...
As a result, uranium deposits were mined during this time without the economic costs of production being the top priority and with little consideration of the risks associated with uranium mining. From the early 1980s, uranium prices have essentially followed the fluctuations of oil prices (Figure 3.22)
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. FIGURE 3.22 History of monthly inflation-adjusted spot uranium prices and oil prices from 1974 to 2011, together with the major accidents at nuclear power plants.
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Spot uranium prices -- usually representing less than 20 percent of supply -- are published by the independent market consultants Ux Consulting and TradeTech (e.g., Figure 3.22)
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The Chernobyl (Ukraine) nuclear accident in 1986 did not have a significant impact on uranium prices, and it is too early to know the long-term uranium demand and price effects of the Fukushima (Japan)
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