Updated

A conservation group and the Nez Perce Tribe have filed a lawsuit against three federal agencies seeking to stop a central Idaho gold-mine exploration project by a Canadian company.

The tribe and the Idaho Conservation League filed the lawsuit Tuesday in U.S. District Court in Idaho against the U.S. Forest Service, U.S. Fish and Wildlife Service and the National Oceanic and Atmospheric Administration's National Marine Fisheries Service.

The lawsuit contends the agencies didn't adhere to federal environmental laws in approving the three-year Golden Meadows Exploration Project proposed by Midas Gold Inc., a Boise-based branch of Midas Gold Corp., headquartered in Vancouver in British Columbia, Canada.

Company officials in Boise didn't return a call from The Associated Press on Thursday.

The company wants to drill about 178 exploratory holes in 26 areas. The plan includes using roads running through the Payette and Boise national forests in Valley County. The company hopes to determine the feasibility of creating three open-pit gold mines. The area has a history of gold mining.

The lawsuit said the plan calls for 43,800 one-way vehicle trips over the three years to move equipment and bring in about three million gallons of fuel. The routes follow winding roads near the South Fork of the Salmon River and two of its tributaries — Johnson Creek and the East Fork of the South Fork of the Salmon River.

Those streams contain chinook salmon, steelhead and bull trout, each listed as threated under the Endangered Species Act.

The Forest Service in July issued an Environmental Assessment of the project, and the federal agencies late last year approved the project after issuing a notice finding that it would cause no significant impact.

The lawsuit contends the Forest Service should have done a more involved environmental impact statement and considered sediment buildup in streams because of increased truck traffic. The lawsuit also says the Forest Service failed to fully consider the potential hazards of fuel spills.

The Forest Service's failure to carry out a more thorough study is a violation of the National Environmental Protection Act, the lawsuit says. That act requires the agency to consider detailed information concerning environmental impacts and that the information be made public.

Dave Olson, public affairs officer for the Boise National Forest, said Thursday that the agency couldn't comment on pending litigation.

The lawsuit contends that because the Forest Service failed to adequately study the plan, the Biological Assessment it provided to the other two federal agencies isn't valid.

That means, the lawsuit said, that NOAA and the Fish and Wildlife Service are violating the Endangered Species Act by signing off on the Forest Service's approval of the exploratory project.

Officials at NOAA declined to comment. Fish and Wildlife Service didn't return a call from the AP on Thursday.

The tribe says the project violates its 1855 treaty with the United States that gives tribal members rights for fishing, hunting, gathering berries, pasturing horses and other rights on lands in and bordering the reservation.

The tribe on Thursday didn't return a call from the AP.

The lawsuit asks that the Forest Service's Environmental Assessment and finding of no significant impact be vacated. It also asks that NOAA's and the Fish and Wildlife Service's approval of the plan be reversed.

The tribe and the Idaho Conservation League are also seeking court costs.

"The South Fork of the Salmon River and its tributaries are some of the most important remaining habitat for salmon, steelhead and bull trout, and we're concerned about the impacts of using these narrow riverside roads as an industrial corridor," said John Robison, the public lands director at the Idaho Conservation League.