Uranium mining in Arizona

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). [Robert B. Scarborough (1981) "Radioactive Occurrences and Uranium Production in Arizona", US Department of Energy, part 3, GJBX-143-(81).]

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. [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.] Mining stopped in the Monument Valley district in 1969, after producing 8.7 million pounds (3900 tonnes) of uranium oxide, more than has been produced from any other uranium mining district in Arizona. [Robert B. Scarorough (1981) Radioactive Occurrences and Uranium Production in Arizona, part 3, US Department of Energy, GJBX-143(81), p.264.] 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. [Robert B. Scarborough (1981) "Radioactive Occurrences and Uranium Production in Arizona", US Department of Energy, part 3, GJBX-143-(81).]

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. [Robert B. Scarborough (1981) "Radioactive Occurrences and Uranium Production in Arizona", US Department of Energy, part 3, GJBX-143-(81).]

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 in diameter, and may extend up to 3000 feet vertically.

ierra 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. [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.]

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. [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.] The Anderson mine is now owned by Concentric Energy Corp. which is doing extensive development work to bring it into production. [ [http://www.concentricenergy.com Concentric Energy Corp. website] ]

Current activity

There are currently no producing uranium mines in Arizona. Denison Mines plans to begin mining its Arizona One mine in 2007. [http://www.denisonmines.com/files/objects/070320.pdf] The deposit is in a breccia pipe on the Colorado Plateau of northern Arizona. [N. Niemuth, "Arizona", Mining Engineering, May 2007, p.70.]

References

See also

* Arizona breccia pipe uranium mineralization
* Uranium mining in the United States