A federal mining law apparently was good enough when President Ulysses S. Grant signed it in 1872. The law allowing prospecting on federal lands unleashed a rush by miners who staked claims and hopes on the mineral riches of the West.

But a century later, the law is under siege. Some lawmakers and conservationists say that despite many amendments, it still lets speculators snap up public land for 19th century prices and leave an environmental mess when they're through."It's at least 100 years out of date," said Mike Medberry of the Idaho Conservation League. "It doesn't allow for protection of the environment. It desperately needs a change."

Among those opposing such change are members of Idaho's congressional delegation, which has defended the 1872 law before and is preparing to again.

They have the backing of miners, who argue that environmental guidelines answer environmental concerns and that revamping the mining law could put small prospectors out of business.

"One hundred years ago, we had a lot of sloppy miners," said Pat Holm-berg of the Independent Miners Association, a regional group with 600 members. "It's not that way now."

The law applies to hardrock minerals, which include gold, silver, uranium, copper, lead and zinc. The U.S. Bureau of Mines says there are about 130,000 active hardrock miners nationwide.

The law was designed to promote mineral exploration and development on federal land, which covers 724 million acres, mostly in 11 Western states and Alaska. It applies to everyone from lone prospectors to major mining companies.

By the end of last year, more than 6 million mining claims had been filed with the government, and 1.2 million were active.

Claimants get title to the parcels by patenting them for $2.50 to $5 an acre - the price of grazing and farm land in 1872. Under the current law, prospectors need to have spent $500 on a claim to qualify for the patent.

Reform proponents planned to introduce legislation in Congress to make miners pay royalties similar to those paid by companies that lease land from the government to extract oil, coal and natural gas.

Sen. Dale Bumpers, D-Ark., is submitting a bill like one he pushed last session, and Rep. Nick Rahall, D-W.Va., has a similar bill for the House, aides said.

The current law had a champion in recently retired Idaho Sen. James McClure, who was the ranking Republican on the Senate Energy and Natural Resources Committee.

Idaho's Republican Sens. Steve Symms and Larry Craig have vowed to carry on McClure's effort.

"The general premise is that anything written in 1872 can't be applicable to today," Craig said.