Interior Secretary Ken Salazar put the brakes on new uranium mining claims on more than a million acres near the Grand Canyon today, saying a temporary moratorium will allow federal agencies to complete an environmental review and decide whether claims should be halted for a longer period.

"I am calling a two-year ‘Time-Out," Salazar said, in a news release. Depending on the results of the environmental review, the department could order a ban on new claims for 20 years, although claims that have already been made will be allowed to continue.

Plans to dig for uranium on the canyon’s rim had been racing ahead under the Bush administration despite concerns that the project could threaten one of the country’s most cherished parks as well as  the water quality of the Colorado River, which supplies drinking water for one in 12 Americans. According to the Environmental Working Group, a Washington, D.C.-based advocacy group, the number of mining claims near the canyon increased from 110 to more than 8,000 between 2003 and 2008.

ProPublica reported on this and other resource development along the Colorado River in an in-depth article last year. It found that the state and federal agencies that govern mining and oil and gas development along the river did not have a coordinated plan for measuring the impact on water resources, or managing the river along its 1,400-mile length. Some of the most intense opposition to drilling and uranium development has come from the cities that depend on the Colorado for irrigation and drinking water, including Las Vegas, Los Angeles and San Diego.