Uranium mining in the United States is the extraction of uranium-bearing ore from the earth. While uranium is used primarily for nuclear power, uranium mining had its roots in the production of uranium-bearing ore in 1898 with the mining of carnotite-bearing sandstones of the Colorado Plateau in Colorado and Utah, for their vanadium content. The late 1940s and early 1950s saw a boom in uranium mining in the western U.S., spurred by the fortunes made by prospectors such as Charlie Steen. The United States was the world's leading producer of uranium from 1953 until 1980, when annual U.S. production peaked at 16,810 metric tons U3O8.[1] Until the early 1980s, there were active uranium mines in Arizona, Colorado, New Mexico, South Dakota, Texas, Utah, Washington, and Wyoming.[2]
Price declines in the late 1970s and early 1980s forced the closure of numerous mines. Most uranium ore in the United States comes from deposits in sandstone, which tend to be of lower grade than those of Australia and Canada. Because of the lower grade, many uranium deposits in the United States became uneconomic when the price of uranium declined sharply in the late 1970s. By 2001, there were only three operating uranium mines (all in-situ leaching operations) in the United States. Annual production reached a low of 779 metric tons of uranium oxide in 2003, but then more than doubled in three years to 1672 metric tons in 2006, from 10 mines.[3] The U.S. DOE's Energy Information Administration reported that 90% of U.S. uranium production in 2006 came from in-situ leaching.[3]
The average spot price of uranium oxide (U3O8) increased from $7.92 per pound in 2001 to $39.48 per pound ($87.04/kg) in 2006.[4] In 2001 the United States mined only 5% of the uranium consumed by its nuclear power plants. The remainder was imported, principally from Russia (50%), Canada, and Australia.[5][6] Although uranium production has declined to low levels, the United States has the fourth-largest uranium resource in the world, behind Australia, Canada, and Kazakhstan.[5] United States uranium reserves are strongly dependent on price. At $30 per pound U3O8, reserves are estimated to be 265 million pounds (120,000 metric tons); however, at a price of $50 per pound, reserves are an estimated 890 million pounds (400,000 metric tons).[7] Rising uranium prices since 2001 have increased interest in uranium mining in Arizona, Colorado, Texas and Utah.[8][4] The states with the largest known uranium ore reserves (not counting byproduct uranium from phosphate) are (in order) Wyoming, New Mexico, and Colorado.[9]
The radiation hazards of uranium mining and milling were not appreciated in the early years, resulting in workers being exposed to high levels of radiation. Inhalation of radon gas caused sharp increases in lung cancers among underground uranium miners employed in the 1940s and 1950s.[10][11][12] In 1950, the US Public Health service began a comprehensive study of uranium miners, leading to the first publication of a statistical correlation between cancer and uranium mining, released in 1962.[13] In 1969, the federal government regulated the standard amount of radon in mines.[14] In 1990, Congress passed the Radiation Exposure Compensation Act (RECA), granting reparations for those affected by mining.[13] Out of 50 present and former uranium milling sites in 12 states, 24 have been abandoned, and are the responsibility of the US Department of Energy.[15]
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Uranium in Alabama is found in the Coosa Block of the Northern Alabama Piedmont. Metamorphic uranium occurrences have been found in the Higgins Ferry Group in Coosa and Clay Counties. Some exploration has been done, but no economic deposits have been found to date.
Uranium was discovered at the Ross-Adams deposit in 1955 by an airborne gamma radiation survey. The deposit is at Bokan Mountain on Prince of Wales Island. The principal ore mineral was uranothorite, which occurred in veinlets in granite. Accessory minerals were primarily hematite and calcite, with lesser amounts of fluorite, pyrite, galena, quartz, and rare earth minerals. The first mining was done in 1957, when ore was removed from an open pit 25 to 75 feet (8 to 23 m) wide, 370 feet (110 m) long, and 30 feet (9 m) deep. Additional mining took place in 1959-1964 and 1970-1971 [16] A total of 1.3 million pounds (590 t) of uranium were produced, with all of the milling taking place in Washington and Utah. There is a firm looking at the potential of reopening the mine.[17]
Uranium mining in Arizona has taken place since 1918. Prior to the uranium boom of the late 1940s, uranium in Arizona was a byproduct of vanadium mining of the mineral carnotite. There is currently a Denison Mines mining operation located several miles outside Fredonia, AZ.
Uranium was discovered in 1954 in the Sierra Nevada of Kern County, along the Kern River about 30 miles (50 km) northeast of Bakersfield. Two mines, the Kergon mine and the Miracle mine, made small shipments in 1954 and 1955. Uranium occurs as uraninite and autunite in shear zones in granodiorite. Accessory minerals include fluorite and the molybdenum minerals ilsemanite and jordisite.[18]
The first uranium identified in the USA was pitchblende from the Wood gold mine at Central City, Colorado in 1871. Uranium mining in southwest Colorado goes back to 1898. The Uravan district of Colorado and Utah supplied about half the world's radium from 1910 to 1922, and vanadium and uranium were byproducts. The only currently active uranium mine in the state is the Sunday mine near Uravan, Colorado, owned by Denison Mines.[19]
The central-Florida phosphorite deposits are considered to contain the largest known uranium resource (one million metric tons of uranium oxide) in North America (but note that resources are not the same as ore reserves). Uranium has been produced as a byproduct of phosphate mining and the production of phosphoric acid fertilizer. The uranium is contained in the phosphate minerals francolite, crandallite, millisite, wavellite, and vivianite, found in Miocene and Pliocene sediments of the Bone Valley Formation. The average uranium content is 0.009%.[20] However, because the recovery process costs an estimated $22 to $54 per pound of U3O8, more than the price of uranium from the 1980s through the early first decade of the 21st century, uranium has not been recovered from Florida phosphate since 1998.[21] Because of the high price of uranium since 2003, uranium recovery may be reactivated.[22]
From 1955 to 1960, uranium was extracted from placer black sand deposits derived from the Idaho Batholith in southwest Idaho. The deposits were mined for uranium, thorium, and rare earths. Uranium and thorium were in the monazite grains; rare earths were in columbite and euxenite. Production was 365,000 pounds (165 metric tons) of U3O8.[23]
Uranium was mined at the Stanley district in Custer County, Idaho from 1957 to 1962. Deposits occur as veins in granite of the Cretaceous Idaho Batholith, and in strataform deposits in possibly Paleocene arkosic conglomerates and sandstones between the underlying Idaho Batholith and overlying Challis Volcanic Group (Eocene). The USGS has estimated production to be less than 170,000 pounds (78 metric tons) of U3O8.[24]
The only uranium mine in Nebraska has been the Crow Butte mine, operated by Cameco. The mine is five miles (8 km) southeast of Crawford in Dawes County, western Nebraska.[25] The roll-front deposit in the Oligocene Chadron formation was discovered in 1980 by Wyoming Fuel Co.[26] Mining began in 1991. The uranium is being mined by in-situ leaching.
The uranium deposit of the Apex mine (also called the Rundberg mine or the Early Day mine) was discovered in 1953, three miles south of Austin, Nevada, in Lander County. The mine produced 45 metric tons of U3O8 from 1954 until the mine was closed in 1966. Uranium occurs as autunite and meta-autunite in fractured Cambrian quartzite and argillite, adjacent to Jurassic quartz monzonite.[27]
The McDermitt Caldera in Humboldt County was the site of intense uranium exploration in the late 1970s. Western Uranium Corporation is currently drilling exploratory boreholes in the area.[5]
A uranium exploration project in northern New Jersey was halted in 1980 when the local government passed an ordinance preventing uranium mining.[28]
New Mexico was a significant uranium producer since the discovery of uranium by Navajo sheepherder Paddy Martinez in 1950. Uranium in New Mexico is almost all in the Grants mineral belt, along the south margin of the San Juan Basin in McKinley and Cibola counties, in the northwest part of the state.[29] No mining has been done since 2002, even though the state has second-largest known uranium ore reserves in the U.S.
Some lignite coal in southwest North Dakota contains economic quantities of uranium. From 1965 to 1967 Union Carbide operated a mill near Belfield in Stark County to burn uraniferous lignite and extract uranium from the ash. The plant produced about 150 metric tons of U3O8 before shutting down.[30]
A small amount of uranium ore was mined in the mid-1950s from a surface exposure at Cement in Caddo County. The uranium occurred as carnotite and tyuyamunite in fracture fillings in the Rush Springs Sandstone over the Cement anticline, where the sandstone is bleached.[31] The mined area was 150 feet (46 m) long, 3 to 5 feet (0.9 to 1.5 m) wide, and extended 3 to 5 feet (0.9 to 1.5 m) below ground surface.[32]
Uranium was discovered in Oregon in 1955, near Lakeview in Lake County. The White King mine and the Lucky Lass mine shipped uranium from 1955 until 1965. At the White King mine, uranium was mined by both underground and open-pit methods from a low-temperature hydrothermal deposit in Pliocene volcanic rocks, associated with opal, realgar, stibnite, cinnabar, and pyrite. At the Lucky Lass mine, the uranium without the associated minerals was mined from an open pit.[33]
A minor amount of uranium was mined in 1960 from a deposit at Bear Creek Butte in Crook County. The uranium was present as autunite at the contact between a rhyolite dike and tuffs of the Oligocene-Miocene John Day Formation.
The uranium mineral autunite was reported in 1874 near the town of Mauch Chunk (present-day Jim Thorpe) in Carbon County, eastern Pennsylvania.[34] A small amount of test mining was done in 1953 at the Mount Pisgah deposit near Jim Thorpe. The uranium at the Mount Pisgah deposit is primarily in an unidentified black mineral in pods and rolls in the basal conglomerate of the Mauch Chunk Formation (Mississippian). Also present are the secondary uranium and uranium-vanadium minerals carnotite, tyuyamunite, liebigite, uranophane, and betauranophane.[35]
Uranium was discovered near Edgemont, South Dakota in 1951, quickly followed by mining. The uranium occurs in Cretaceous sandstones of the Inyan Kara group, where it outcrops along the southern edge of the Black Hills in Fall River County, South Dakota. Minerals in unoxidized sandstone are uraninite and coffinite; minerals in oxidized zones include carnotite and tyuyamunite.[36]
An airborne gamma radiation survey flown by the US Atomic Energy Commission in 1954 discovered high radiation readings over the Cave Hills area in Harding County, in the northwest corner of the state.[37] High winds blew the reconnaissance flight off their planned survey route over the Slim Buttes twenty miles southeast of the North Cave Hills. Claims were immediately staked over uranium-bearing lignite beds in the area. The lignite was strip-mined, probably starting that same year, and continuing until the mines closed in 1964.[38]
No uranium is currently mined in South Dakota.
In January 2007 [39] received a state permit to drill boreholes to evaluate their Dewey-Burdock project, in Custer and Fall River counties northwest of Edgemont.[40] Previous work at the property in the early 1980s defined a resource of 10 million pounds (4500 metric tons) of uranium, of which 5 million pounds (2300 metric tons) were estimated recoverable by conventional underground mining.[41] Powertech hopes to bring the property into production as an in-situ leaching mine in 2009.[42]
A campaign has been underway to halt any effort to mine uranium in the Black Hills because of its effect on Native American and wildlife populations, as well as the effects of mining on the water table and local ranchers.[43][44] Indigenous leaders and anti-nuclear activists began organizing around this issue in the 1970s and there are still efforts underway to prevent mining on native lands.[45][46]
The uranium district of south Texas was discovered by accident in 1954 by an airborne gamma radiation survey looking for petroleum deposits. The coastal plain had previously been regarded as highly unfavorable for uranium deposits.[47] The uranium occurs in roll-front type deposits in sandstones of Eocene, Oligocene and Miocene age.[48] The deposits are distributed along about 200 miles (320 km) of coastal plain, from Panna Maria in the north, south into Mexico. Uranium production began in 1958, from open-pit and in situ leach mines.
Uranium production stopped in 1999, but restarted in 2004.[49] By 2006, three mines were active: Kingsville Dome in Kleberg County, the Vasquez mine in Duval County, and the Alta Mesa mine in Brooks County. 2007 production was 1.34 million pounds (607 metric tons) of U3O8.[50]
Uranium Energy Corp. began in-situ leach mining at its Palangana deposit in Duval County in 2010; the company has three more South Texas deposits which it hopes to mine.[51]
Mining of uranium-vanadium ore in southeast Utah goes back to the late 19th century. All of Utah’s numerous uranium mines closed prior to 2000, because of low prices. In late 2006, Denison Mines reopened the Pandora mine in the La Sal mining district of southeastern Utah.
Marline Uranium Corp. announced in July 1982 that it had discovered 110 million pounds (50,000 metric tons) of uranium in the Swanson/Coles Hill deposit, on land that it had leased near Chatham in Pittsylvania County. During the 1982 legislative session, the state of Virginia adopted laws to govern exploration for uranium in the Commonwealth. At the same time, the legislature imposed a moratorium on uranium mining in the state until such time that regulations to govern uranium mining could be enacted into law.[6]
In 1981, the Virginia General Assembly approved House Joint Resolution No. 324, which directed the Virginia Coal and Energy Commission to evaluate the effects of uranium development on the Commonwealth and its citizens. The Virginia Coal and Energy Commission is a permanent legislative commission composed of five Senators, eight Delegates, and seven citizens appointed by the Governor.
The Commission completed its evaluation of uranium mining in October 1984 and concluded that the moratorium regarding uranium development could be lifted on the condition that certain specific recommendations derived from its work would be enacted into law.
Union Carbide was the joint venture partner on the project with Marline until early 1984 when it dropped its option on the property due to declining uranium prices. Marline kept the project on care and maintenance until 1990, when it dropped its remaining mineral leases and closed its local exploration office.[7]
The deposits occur as breccia-fill and veins in gneiss bordering the Triassic Danville Basin.[52] Ore minerals are coffinite, uraninite, and uranium-bearing apatite.[8]
In October 2007, Walter Coles, who owns the land over the Coles Hill deposit, announced that he and some other landowners had formed Virginia Uranium Inc. to mine the deposit themselves, if it can be done safely.[9][10] In November 2007, the state issued an exploration permit to Virginia Uranium, to allow drilling test holes into the deposit. Drilling began in mid-December.
The state-imposed moratorium on uranium mining is still in effect. A bill proposed in the state General Assembly in January 2008 would have created a Virginia Uranium Mining Commission to determine if uranium mining could be done in a manner protective of human health and the environment, and to recommend regulatory controls.[11] The bill passed the Democratic controlled state Senate by a vote of 36-4. However, opponents of uranium mining succeeded in stopping the bill on March 3, 2008, when Rules Committee of the Republican controlled House of Delegates delayed consideration of the bill until 2009.[12]
In November 2008, the Virginia Coal and Energy Commission voted unanimously to once again create a subcommittee to study the issue of uranium mining.[53] In May 2009 the subcommittee approved a study of potential uranium mining and its safety and pollution issues. The study is expected to take about 18 months to complete.[54]
In February 2010, the Commonwealth of Virginia contracted the National Research Council and Virginia Polytechnic Institute to oversee a National Research Council study of potential environmental and economic effects of uranium mining in Virginia. The National Research Council study, funded indirectly by a $1.4 million grant from Virginia Uranium to the Commonwealth, resulted in a report released in December 2011.[55]
The report identified a range of health and environmental issues and related risks that could result from uranium mining in the Commonwealth of Virginia. The report found that although there are internationally accepted best practices to mitigate some risks, Virginia faces “steep hurdles” if it is to undertake uranium mining and processing within a regulatory setting that appropriately protects workers, the public, and the environment.[56]
Uranium mining and processing carries with it a range of potential health risks to the people who work in or live near uranium mining and processing facilities. Some of these health risks apply to any type of hard rock mining or other large-scale industrial activity, but others are linked to exposure to radioactive materials. In addition, uranium mining has the potential to impact water, soil, and air quality, with the degree of impact depending on site-specific conditions, how early a contaminant release is detected by monitoring systems, and the effectiveness of mitigation steps.[57]
Some of the worker and public health risks could be mitigated or better controlled through modern internationally accepted best practices, the report says. In addition, if uranium mining, processing, and reclamation were designed, constructed, operated, and monitored according to best practices, near- to moderate-term environmental effects should be substantially reduced, the report found. [58]
However, the report noted that Virginia’s high water table and heavy rainfall differed from other parts of the United States — typically dry, Western states — where uranium mining has taken place. Consequently, federal agencies have little experience developing and applying laws and regulations in locations with abundant rainfall and groundwater, such as Virginia. Because of Virginia’s moratorium on uranium mining, it has not been necessary for the Commonwealth’s agencies to develop a regulatory program that is applicable to uranium mining, processing, and reclamation.
The report also noted the long-term environmental risks of uranium tailings, the solid waste left after processing. Tailings disposal sites represent potential sources of contamination for thousands of years. While it is likely that tailings impoundment sites would be safe for at least 200 years if designed and built according to modern best practices, the long-term risks of radioactive contaminant release are unknown.
The report’s authoring committee was not asked to recommend whether uranium mining should be permitted, or to consider the potential benefits to the state were uranium mining to be pursued. It also was not asked to compare the relative risks of uranium mining to the mining of other fuels such as coal.
Uranium was discovered at the Midnite Mine deposit on the Spokane Indian Reservation, Stevens County, Washington in 1954. The deposit was mined from an open pit 1956-1962 and 1969-1982.[59] Production through 1975 was 8 million pounds (3,600 metric tons) of U3O8. The uranium is contained in autunite, uraninite, and coffinite, with gangue minerals pyrite and marcasite. The ore occurs as disseminations, replacements, and stockworks in Precambrian metamorphic rocks of the Togo formation, in a roof pendant in Cretaceous porphyritic quartz monzonite.[60]
Western Nuclear discovered the Spokane Mountain uranium deposit in 1975, two miles (3 km) northeast of the Midnite Mine, and in a similar geologic setting.[61]
Other Washington state uranium mines include the Sherwood mine, located a few miles south of the Midnite mine, and the Daybreak mine, located about four miles west-northwest of Mt. Spokane. The Daybreak mine is recognized as the source of the finest museum-quality specimens of autunite and meta-autunite yet found.[62]
Wyoming once had many operating uranium mines, and has the largest known uranium ore reserves of any state in the U.S. The Wyoming uranium mining industry was hard-hit in the 1980s by the drop in the price of uranium. The uranium-mining boom town of Jeffrey City lost 95% of its population in three years. By 2006, the only active uranium mine in Wyoming was the Smith Ranch-Highland in-situ leaching operation in the Powder River Basin, owned by a subsidiary of Cameco. The mine produced 907 metric tons of yellowcake (uranium concentrate) in 2006, making it the leading uranium producer in the United States.[63]
The radiation hazards of uranium mining and milling were not appreciated in the early years, resulting in workers exposed to high levels of radiation. Inhalation of radon gas caused sharp increases in lung cancers among underground uranium miners employed in the 1940s and 1950s.[64][65][66]
In 1950, the US Public Health service began a comprehensive study of uranium miners, leading to the first publication of a statistical correlation between cancer and uranium mining, released in 1962.[13] The federal government eventually regulated the standard amount of radon in mines, setting the level at 0.3 WL on January 1, 1969.[14] In 1990, Congress passed the Radiation Exposure Compensation Act (RECA), granting reparations for those affected by mining, with amendments passed in 2000 to address criticisms with the original act.[13]
Uranium mines also create radioactive waste in the form of tailings, which contain uranium, thorium, radium, and polonium. Consequently, uranium mining results in "the unavoidable radioactive contamination of the environment by solid, liquid and gaseous wastes".[67]
In the 1940s and 1950s, uranium mill tailings were released with impunity into water sources, and the radium leached from these tailings contaminated thousands of miles of the Colorado River system. Between 1966 and 1971, thousands of homes and commercial buildings in the Colorado Plateau region were "found to contain anomalously high concentrations of radon, after being built on uranium tailings taken from piles under the authority of the Atomic Energy Commission".[68]
Out of 50 present and former uranium milling sites in 12 states, 24 have been abandoned, and are the responsibility of the US Department of Energy.[69] Accidental releases from uranium mills include the 1979 Church Rock uranium mill spill in New Mexico, called the largest accident of nuclear-related waste in US history, and the 1986 Sequoyah Corporation Fuels Release in Oklahoma.[14]
After the end of World War II, the United States encouraged uranium mining production because of the nuclear arms race with the U.S.S.R., its opponent in the Cold War. Large uranium deposits were found on and near the Navajo Reservation in the Southwest, and private companies hired many Navajo employees to work the mines. Disregarding the known health risks imposed by exposure to uranium, the private companies and the United States Atomic Energy Commission failed to inform the Navajo workers about the dangers and to regulate the mining to minimize contamination. As more data was collected, they were slow to take appropriate action for the workers.
Studies provided data to show that the Navajo mine workers and numerous families on the reservation have suffered high rates of disease from environmental contamination, but for decades, industry and the government failed to regulate or improve conditions, or inform workers of the dangers. As high rates of illness began to occur, workers were often unsuccessful in court cases seeking compensation, and the states at first did not officially recognize radon illness. In 1990 the US Congress passed the Radiation Exposure Compensation Act, to settle such cases and provide needed compensation.
In 2008 the US Congress authorized a five-year, multi-agency cleanup of uranium contamination on the Navajo Nation reservation; identification and treatment of contaminated water and structures has been the first priority. Certain water sources have been closed, and numerous contaminated buildings have been taken down. By the summer of 2011, EPA had nearly completed the first major project of removal of 20,000 cubic yards of contaminated earth from the Skyline Mine area.