FLAGSTAFF, Ariz. (AP) – The Interior Department has extended a temporary ban on the filing of new mining claims near the Grand Canyon with an eye toward protecting 1 million acres and giving the federal government more time to study the economic and environmental effects of mining.

The department has been analyzing whether to prohibit new mining claims on up to 1 million acres near the park, or allow the mining industry to add to the thousands of claims already staked in the area. A temporary ban enacted in July 2009 was set to expire next month but will now last until December.

Interior Secretary Ken Salazar visited the Grand Canyon and drew on its history to urge patience, caution and humility in moving forward with what has been a controversial process.

“Cautious development with strong oversight could help us answer critical questions about water quality and environmental impacts of uranium mining in the area,” he said. “This science, derived from experience, would help others decide what actions are necessary to protect the Grand Canyon.”

The withdrawal of the full 1 million acres for 20 years will be identified as the department's preferred alternative when the analysis is completed later this year, Salazar said. The mining industry, along with Gov. Jan Brewer and some Republican members of Congress quickly blasted Salazar's decision as detrimental to the state's economy and the country's energy independence.

Conservationists hailed the announcement as crucial to protecting the area's natural and cultural resources. Ranchers had sent miniature cowboy hats to Salazar, a rancher himself and former natural resources chief in Colorado, urging a more permanent withdrawal for what mining opponents have said was a natural treasure under threat.

The temporary ban was meant to slow a flurry of new uranium mining operations planned near the Grand Canyon. At least 3,350 active mining claims exist for all types of hard-rock exploration within the 1 million acres.

The Interior Department released four proposals in February – to take no action, to set aside the 1 million acres for 20 years, or to partially withdraw either 300,000 or 650,000 acres from any new claims. The public weighed in with hundreds of thousands of comments.

Most of the claims for uranium are staked in the Arizona Strip, a sparsely populated area immediately north of the Grand Canyon's boundaries known for its high-grade uranium ore. Mining supporters say prohibiting new claims for one of the country's most prolific uranium reserves would keep hundreds from employment and further harm the economy. They vowed to fight Salazar's decision.

“The whole thing is built on a house of cards,” said Bob Weidner of the American Clean Energy Resources Trust. “While the secretary sounds reasonable saying, `We should wait,' the facts are already out based on experience that there is no link between uranium mining and pollution to the Colorado River.”

Salazar said he was concerned that mining operations could contaminate the Colorado River that runs through the Grand Canyon and other water sources. He also acknowledged the role uranium has played in meeting the country's energy needs.

Environmental groups, American Indian tribes, sportsmen and anglers said the Grand Canyon and the surrounding landscape have suffered too long from the toxic legacy of pollution left by mining operations, and they want it to stop.

“We commend the Obama administration for making a clear commitment to give the Grand Canyon long-term protection from new uranium mining at its doorstep,” said Jane Danowitz, public lands director for the Pew Environment Group. “For decades to come, Americans will benefit from today's far-sighted decision to safeguard this natural icon.”

The protections won't affect mining claims filed before Salazar enacted the temporary ban in 2009. It's not possible to prevent existing claims from being developed under the General Mining Act of 1872 unless Congress appropriates money for the department to buy them.

The withdrawal covers 633,547 acres under the control of the U.S. Bureau of Land Management and 360,002 acres in northern Arizona's Kaibab National Forest. Mining companies would need to prove they have valid existing rights to those claims before mining could occur. Only one company actively is mining in the area. Anywhere from 11 to 30 mines could be developed under existing claims, according to the BLM.