Uranium mining in Arizona
The uranium and vanadium occur as carnotite in sandstone of the Salt Wash member of the Morrison Formation (Jurassic).
Uranium and uranium-vanadium minerals occur in fluvial channels of the Shinarump Sandstone member of the Triassic Chinle Formation.
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] After the end of World War II, the United States encouraged uranium mining to build nuclear weapons stockpiles.
Disregarding the health risks of radiation exposure, 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.
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.
[10] 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.
The deposit was discovered in the 1970s, and partially developed as an underground mine under a Forest Service permit in the late 1980s, but never put into production.
A coalition of groups, including the Havasupai Tribe, the Sierra Club, the Grand Canyon Trust, and the Center for Biological Diversity, sued the Forest Service to stop the reactivation of the mine.
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.
This decision preserves about “1 million acres near the Grand Canyon, an area known to be rich in high-grade uranium ore reserves” and has generated a number of different responses [15] The ban is supported by the president of the League of Conservation voters, Gene Karpinski: "Extending the current moratorium on new uranium mining claims will protect drinking water for millions downstream.” Many environmental groups agree that such mining would endanger the Colorado River as a source of water not only for wildlife, but for tens of millions of people; Phoenix, Las Vegas and Los Angeles rely on the river for drinking water.
According to an Arizona Geological survey, “60 metric tons of dissolved uranium is naturally carried by the Colorado River through the Grand Canyon in an average year".
Spencer, AZGS Senior Geologist, argues that in one hypothetical, worst-case scenario experiment, a truck carrying “thirty metric tons (66,000 pounds) of one-percent uranium ore” spilling and washing into the Colorado River increases the natural uranium level in the river by an insignificant amount.
[17] In 2011 more than 200 Arizona small businesses addressed postcards to Interior Secretary Ken Salazar sign the 20-year ban on new uranium mining near the Grand Canyon, to preserve thousands of tourism-related jobs.
[16] Coconino County Supervisor Carl Taylor argued that Uranium mining poses a great threat to tourism in the canyon and surrounding areas.
[15] Interior Secretary Ken Salazar states that “the Grand Canyon attracts more than 4 million visitors a year and generates an estimated $3.5 billion in economic activity”.
