The Interior Department is moving forward with a plan to ban new mining claims on 1 million acres near the Grand Canyon, even as congressional Republicans try to block efforts to limit mining operations in an area known for high-grade uranium ore.
Interior Secretary Ken Salazar is expected to finalize a 20-year ban on new mining claims on public land surrounding the Grand Canyon at an event Monday in Washington.
Salazar twice imposed temporary bans as officials studied the environmental and economic effects of a longer-term ban.
Conservation groups hailed the 20-year ban, first announced in October, as a crucial protection for an American icon.
The mining industry and some Republican members of Congress called the ban detrimental to Arizona's economy and the nation's energy independence.
Interior Department officials declined to comment, but said Salazar is expected to make an announcement regarding conservation of the Grand Canyon at an event at the National Geographic Museum.
Salazar, in remarks last year, called the Grand Canyon a national treasure that must be protected.
Management of the Grand Canyon and surrounding land "must be guided by caution, wisdom and science," in order to protect the canyon itself, as well as tribal interests, drinking water supplies and the tourism economy that the Grand Canyon supports, Salazar said in a June speech.
Salazar and Bob Abbey, director of the U.S. Bureau of Land Management, said it was appropriate to identify what impact mining would have on the canyon and decide what level of risk is acceptable.
Republican members of Arizona's congressional delegation have lambasted temporary bans imposed by Salazar in 2009 and again last year.
They say a permanent ban on the filing of new mining claims would eliminate hundreds of jobs and unravel decades of responsible resource development.
Rep. Jeff Flake, R-Ariz., and other GOP lawmakers are backing legislation to prevent Salazar from moving forward with the 20-year ban.
Environmental groups call the ban a long-awaited but decisive victory, noting that the Colorado River, which runs through the Grand Canyon, is the source of drinking water for 26 million Americans.
"Secretary Salazar has defended the Southwest's right to plentiful, clean water and America's dedication to one of our most precious landscapes," said Dusty Horwitt, senior counsel for the Environmental Working Group, a Washington-based advocacy group.
"Despite significant pressure from the mining industry, the president and Secretary Salazar did not back down," said Jane Danowitz, U.S. public lands director for the Pew Environment Group.
As outlined in October, the ban would not affect more than 3,000 mining claims already staked in the area near the Grand Canyon.
The Bush administration had opened up the land to new mining claims.
Salazar reversed the Bush policy in 2009 and called for a two-year moratorium on new mining claims around the canyon.
He followed up with a six-month extension last year.
Supporters of the ban say any increase in mining jobs is not worth risks to the Colorado River, lands considered sacred by American Indian tribes or wildlife habitat.
A mining mishap also could be disastrous for tourism in one of the nation's most-visited parks.