The Forest Service placed the area, one of the last undeveloped stretches of the front in the United States, off limits to oil and gas development in 1997. "This is an extraordinary action, required to protect an extraordinary landscape," said Stephen D'Esposito, head of the pro-environment Mineral Policy Center in Washington. "We're thrilled," said Christine Phillips, a conservation organizer with the Sierra Club in Montana.

"We think this gives everyone the opportunity to step back and have a discussion over the appropriateness of mining in such a critical area." The proposal was unveiled byForest Service Chief Michael Dombeck on Wednesday in Montana.

Under the plan, hard rock mining would be barred for two years while the service evaluates the area's future. A permanent ban on hard rock mining was possible. "Many areas are simply not appropriate for certain activities, such as hard rock mining," Dombeck said.

"One such place is the Rocky Mountain Front." There has been little mining development in the Front, a stunning region of the northern Rocky Mountains where high peaks soar out of prairies.

The area is home to elk, deer, mountain goat and is one of the last remaining open habitats of the grizzly bear in the 48 contiguous states. Dombeck said he was proposing the ban because Congress has deadlocked over updating the 1872 law that allows miners to claim federal land and buy it for as little as $2.50 an acre. Dombeck's announcement was termed "very bad news" by the Montana Mining Association, which said the move would hurt economic development and job creation.

"I just can't believethey'd do such a short-sighted, economics-blind thing," Dave Young, the association's president, said in a statement. "It's bad policy to put potentially valuable minerals off-limits to exploration."

But environmentalists disagreed, saying the area covered by the moratorium is widely thought to be have little hard-rock mineral value. "Geologically speaking, these are sea beds wrapped on each other that do have oil and gas potential, but not hard-rock potential," said Bob Decker, executive director of the Montana Wilderness Association.