Another layer of litigation has been added to block development of the Rock Creek Mine proposed just outside the Cabinet Mountain Wilderness.

Ten conservation groups represented by the Earthjustice legal firm filed a lawsuit on Friday challenging the U.S. Fish and Wildlife Service's approval of the mine, which would bore beneath the wilderness area for copper and silver.

A previous lawsuit filed by many of the same groups challenged the U.S. Forest Service's permit for the mine.

The latest lawsuit alleges that the Fish and Wildlife Service violated the Endangered Species Act in issuing a biological opinion that allows mining to proceed even though the project would "severely harm" threatened bull trout and a fragile grizzly bear population.

Spokane-based Revett Minerals Co. maintains that the Rock Creek project includes a variety of measures, costing $18 million, that will effectively mitigate harm to grizzly bears and bull trout.

Plaintiffs in the case say it's not enough.

"The Rock Creek Mine is a mine without a blueprint - the federal government approved it even though much about the mine is unknown and many of the critical decisions about its design will be made later," said Jim Costello of the Rock Creek Alliance. "What we do know is this mine would contaminate the region's water and destroy habitat that is critical for the survival of two threatened species."

The plaintiffs contend the mine will affect more than 7,000 acres within the habitat of the tiny Cabinet-Yaak grizzly bear population. The Fish and Wildlife Service estimates that as few as 30 bears might remain in the recovery area.

The Fish and Wildlife Service issued a second biological opinion in October 2006 after a federal judge ruled that an initial biological opinion was inadequate.

At the time, the service contended that the second biological opinion would withstand legal scrutiny.

"We carefully reviewed our analysis and how we presented our analysis," said Anne Vandehey, the agency biologist who led development of the opinion. "In this opinion, we did our very best to document how we arrived at our decisions."

Once operational, the mine would process about 10,000 tons of rock and ore per day. Revett officials have said the operation would discharge about 2,300 gallons of wastewater per minute into a two-stage processing plant. Processed water would be discharged into Rock Creek.

That translates to flows of about 5 cubic feet per second going into the Clark Fork River, which has average flows of 20,000 cfs, according to the company.

The groups involved in the lawsuits include the Rock Creek Alliance, Cabinet Resources Group, Clark Fork Coalition, Earthworks, Sierra Club, Trout Unlimited, Idaho Council of Trout Unlimited, Pacific Rivers Council, Alliance for the Wild Rockies, Natural Resources Defense Council, the Montana Wilderness Association and Great Old Broads for Wilderness.

Reporter Jim Mann may be reached at 758-4407 or by e-mail at [email protected]