Uranium mining in New Mexico

Uranium mining in New Mexico, a state of the United States, was a significant industry from the early 1950s until the early 1980s. Although New Mexico has the second largest identified uranium ore reserves of any state in the US (after Wyoming), no uranium ore has been mined in New Mexico since 1998.

White Signal district

The first uranium production in New Mexico was a minor amount of autunite and torbernite mined circa 1920 from former silver mines in the White Signal district, about convert|15|mi|km southwest of Silver City in Grant County. [T.G. Lovering (1956) "Radioactive Deposits of New Mexico", US Geological Survey, Bulletin 1009-L, p.329.]

Grants mineral belt

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. Stretching northwest to southeast, the mineral belt contains the Chuska, Gallup, Ambrosia Lake, and Laguna uranium mining districts. [Douglas G. Brookins (1977) "Uranium deposits of the Grants mineral belt: geochemical constraints on origin", in "Exploration Frontiers of the Central and Southern Rockies", Denver: Rocky Mountain Association of Geologists, p.337-352.] Most of the uranium ore is contained in the Jackpile, Poison Canyon, and Westwater Canyon sandstone members of the Morrison Formation, and in the Todilto limestone, all of Jurassic age. [H.C. Granger and others, "Sandstone-type uranium deposits at Ambrosia Lake, New Mexico-an interim report," "Economic Geology", Nov. 1961, p.1179-1210.]

Current activity

Active uranium mining stopped in New Mexico in 1998, although Rio Algom continued to recover uranium dissolved in water from its flooded underground mine workings at Ambrosia Lake until 2002. [S.A. Lucas Kamat, "New Mexico," "Mining Engineering", May 2006, p.107.] No uranium mining is taking place, even though the state has second-largest known uranium ore reserves in the U.S.

General Atomics subsidiary Rio Grande Resources is currently evaluating its Mt. Taylor Mine for development by in-situ leaching. Uranium is present in coffinite in the Westwater Canyon member of the Morrison Formation at 3,000 feet (900 m) below ground surface. The mine, which operated as an underground uranium mine from 1986 to 1989, has a remaining resource estimated by its owner at more than 45 thousand tonnes of uranium oxide. [http://www.ga.com/riogrande.php]

Strathmore Minerals Corp. is currently applying for permits to mine their Church Rock and Roca Honda properties in the Grants Mineral Belt. [http://www.strathmoreminerals.com/s/RocaHonda.asp] Neutron Energy and URI also reportedly plan to start uranium mining in the Grants belt. [http://www.gallupindependent.com/2007/october/103107kh_jmpstrturnmmng.html]

Health and environmental issues

New Mexico uranium miners from the 1940s and 1950s have had abnormally high rates of lung cancer, from radon gas in poorly ventilated underground mines. The effect was particularly pronounced among Navajo miners, because the incidence of lung cancer is normally low among Navajos. The Navajo tribe, whose reservation contains much of the known ore deposits, declared a moratorium on uranium mining in 2005. [S.A. Lucas Kamat, "New Mexico," "Mining Engineering", May 2007, p.103.] In May 2007, the US EPA announced that it would join the Navajo Nation EPA in cleaning up radioactive contamination near the Church Rock mine. [http://yosemite.epa.gov/opa/admpress.nsf/89745a330d4ef8b9852572a000651fe1/eb6de5c6b316e996852572ce0071a707!OpenDocument]

Cited references

ee also

Uranium mining in the United States