Uranium mining in Arizona: Difference between revisions
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For some years starting in 1980, the Twin Buttes copper mine in [[Pima County, Arizona|Pima County]] recovered uranium as a byproduct from leach solutions recovering copper from waste material.<ref>Robert B. Scarborough (1981) ''Radioactive Occurrences and Uranium Production in Arizona'', US Dept. of Energy, GJBX-143(81), p.93.</ref> |
For some years starting in 1980, the Twin Buttes copper mine in [[Pima County, Arizona|Pima County]] recovered uranium as a byproduct from leach solutions recovering copper from waste material.<ref>Robert B. Scarborough (1981) ''Radioactive Occurrences and Uranium Production in Arizona'', US Dept. of Energy, GJBX-143(81), p.93.</ref> |
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==Uranium |
==Uranium mining and the native people== |
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{{Main|Uranium mining and the Navajo people}} |
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Uranium mining caused many Native Americans and animals{{Citation needed|date = April 2010}} to become sick. Some problems were that there was limited amount of water located on the reservation, so locals would have to travel long distances for water. The Mines would leave contaminated waters unattended and would not even put up fences to prevent anyone passing through.{{Citation needed|date = April 2010}} So the native would bring their livestock and gather water at the contaminated area. This caused mutation between the animals and the Native People.{{Citation needed|date = April 2010}} |
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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 [[Southwestern United States|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. |
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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. |
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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. |
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==Current activity== |
==Current activity== |
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Revision as of 13:59, 27 December 2011
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.
Carrizo Mountains
Uranium mining started in 1918 in the Carrizo Mountains as a byproduct of vanadium mining. The district is in Apache County, in the northeast corner of Arizona. The uranium and vanadium occur as carnotite in sandstone of the Salt Wash member of the Morrison Formation (Jurassic). Production stopped in 1921. Another period of mining took place from 1941 to 1966, producing 360,000 pounds (160 metric tons) of uranium oxide (U3O8).[1]
Monument Valley
A Navajo discovered uranium in 1942 in Monument Valley on the Navajo Indian Reservation in northeast Arizona. The first mine in the district opened in 1948. Uranium and uranium-vanadium minerals occur in fluvial channels of the Shinarump Sandstone member of the Triassic Chinle Formation. Ore deposits are associated with carbonized wood in the sandstone.[2] Mining stopped in the Monument Valley district in 1969, after producing 8.7 million pounds (3900 metric tons) of uranium oxide, more than has been produced from any other uranium mining district in Arizona.[3] In 2005 the Navajo Nation declared a moratorium on uranium mining on the reservation, for environmental and health reasons.
Lukachukai Mountains
In 1948, a copper deposit in the Moenkopi Formation was discovered to have economic concentrations of uranium. The deposit was in the Lukachukai Mountains of Apache County. Uranium totaling 3.5 million pounds (1600 metric tons) of U3O8 was produced from 1950 until the mines closed in 1968.[4]
Cameron district
Navajo prospector Hosteen Nez found uranium near Cameron in Coconino County in 1950. The uranium is in the Kayenta Formation and the Chinle Formation. Production was from 1950 to 1963, and totaled 1.2 million pounds (540 metric tons) of U3O8.[5]
Collapse breccia pipes
Uranium was discovered in the Orphan copper mine near the south rim of the Grand Canyon in 1950. The mine has been private property since 1906, and is today completely surrounded by Grand Canyon National Park. The discovery led to the finding of uranium in other collapse breccia pipes in northern Arizona. The breccia pipes were formed when overlying rocks collapsed into caverns formed in the Mississippian Redwall Limestone. The pipes are typically 300 feet (91 m) in diameter, and may extend up to 3,000 feet (910 m) vertically.
Sierra Ancha district
Uranium mining started in 1953 from deposits in the Precambrian Dripping Springs Quartzite in Gila County. The uranium mineral is most commonly uraninite, which occurs with pyrite, marcasite, and chalcopyrite. The orebodies are in veins or strataform deposits within one-half mile of diabase intrusions.[6]
Date Creek Basin
The Anderson uranium deposit was discovered in 1955 by an airborne gamma-radiation survey. Small amounts of ore were produced from 1955 to 1959. Uranium is associated with organic material in carbonaceous Miocene siltstones and mudstones of lacustrine and paludal origin of the Chapin Wash formation of the Date Creek Basin in Yavapai, La Paz, and Mohave counties.[7] The Anderson mine is now owned by Concentric Energy Corp. which is doing extensive development work to bring it into production.[8]
Porphyry copper byproduct
For some years starting in 1980, the Twin Buttes copper mine in Pima County recovered uranium as a byproduct from leach solutions recovering copper from waste material.[9]
Uranium mining and the native people
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.
Current activity
There are currently no producing uranium mines in Arizona. Denison Mines plans to begin mining its Arizona One mine in 2007.[10] The deposit is in a breccia pipe on the Colorado Plateau of northern Arizona.[11] In March 2011, the State of Arizona issued air and water permits to Denison which would allow uranium mining to resume at three locations north of the Grand Canyon, subject to federal approval.[12]
In July 2009 Secretary of the Interior Ken Salazar announced a two-year ban on new mining on federal land in an area of approximately 1 million acres (4,000 km2) surrounding Grand Canyon National Park. Although the ban is on all mining, the main effect is on exploration and development of breccia-pipe uranium deposits. Those claims on which commercial mineral deposits have already been discovered are exempt from the ban. During the two-year ban the Department of the Interior will study a proposed 20-year ban on new mining in the area.[13]
References
- ^ Robert B. Scarborough (1981) Radioactive Occurrences and Uranium Production in Arizona, US Department of Energy, part 3, GJBX-143-(81).
- ^ Roger C. Malan (1968) The uranium mining industry and geology of the Monument Valley and White canyon districts, Arizona and Utah, in Ore Deposits of the United States, 1933-1967, New York: American Institute of Mining Engineers, p.790-804.
- ^ Robert B. Scarorough (1981) Radioactive Occurrences and Uranium Production in Arizona, part 3, US Department of Energy, GJBX-143(81), p.264.
- ^ Robert B. Scarborough (1981) Radioactive Occurrences and Uranium Production in Arizona, US Department of Energy, part 3, GJBX-143-(81).
- ^ Robert B. Scarborough (1981) Radioactive Occurrences and Uranium Production in Arizona, US Department of Energy, part 3, GJBX-143-(81).
- ^ A.P. Butler Jr. and V.P. Byers (1969) Uranium, in Mineral and Water Resources of Arizona, Arizona Bureau of Mines, Bulletin 180, p.288.
- ^ Andreas Mueller and Peter Halbach, The Anderson mine (Arizona)-an early diagenetic uranium deposit in Miocene lake sediments, Economic Geology, Mar.-Apr. 1983, p.2475-292.
- ^ Concentric Energy Corp. website
- ^ Robert B. Scarborough (1981) Radioactive Occurrences and Uranium Production in Arizona, US Dept. of Energy, GJBX-143(81), p.93.
- ^ Denison Mines, Arizona Strip uranium project, PDF file.
- ^ N. Niemuth, "Arizona," Mining Engineering, May 2007, p.70.
- ^ http://www.kpho.com/arizona/27163219/detail.html
- ^ "Two-year ban on mining near Grand Canyon imposed," Mining Engineering, September 2009, p.7.