HELENA, Mont. — The Forest Service says a company seeking to develop a copper and silver mine beneath the Cabinet Mountains Wilderness in northwestern Montana can begin digging this winter, now that the agency has reviewed its decision to allow the project.

Mine developer Revett Minerals said Thursday it is ready to begin in 60 days, but critics are skeptical it will happen that soon.

In a letter this week, Kootenai National Forest officials told Revett the company is authorized to start work under terms of a 2003 decision by the Forest Service and the Montana Department of Environmental Quality. A review, in the wake of a court ruling, found no new issues affecting the decision, the Forest Service said. Consequently, it need not be revised nor is a supplemental environmental study required, the agency said.

"We're prepared to go in 60 days if there are no further delays in the courts," said William Orchow, chief executive for Washington-based Revett.

Although the mine would be beneath the Cabinet Mountains Wilderness, Revett has said disturbance of the ground would be outside of wilderness boundaries.

Critics of the mine have include jeweler Tiffany & Co., which in 2004 bought a full-page ad in The Washington Post declaring the area more valuable for wildlife than for minerals.

Last year, however, the U.S. Fish and Wildlife Service said grizzly bears stood to benefit if mining proceeds, noting Revett's mitigation measures — such as buying land to protect as grizzly habitat — would leave the bears in better condition than if the mine was not developed. The agency also endorsed Revett's plans for protection of sensitive bull trout.

Tim Preso with Earthjustice said this week's decision was based on a flawed analysis of likely environmental effects, including effects on grizzlies and bull trout. Two lawsuits challenging the mine are pending, he said. Matt Clifford of the Clark Fork Coalition in Missoula described the mine as "not going anywhere fast."

Revett said the next step in mine development involves establishing a horizontal passage into the earth, then drilling to verify technical aspects of the proposed project. The company anticipates the mine would take two years to develop, and would operate for 20 years.

On the Net:

Revett Minerals: www.revettminerals.com

Earthjustice: www.earthjustice.org