Conservation groups sued the U.S. Fish and Wildlife Service, U.S. Forest Service and U.S. Army Corps of Engineers Tuesday, saying their approval of the PolyMet open-pit copper mine and land exchange in the Superior National Forest in northeastern Minnesota violates the Endangered Species Act.

The 528-acre open-pit mine would destroy important habitat for the Canada lynx and northern long-eared bat, both listed as threatened with extinction under the Act.

“These federal agencies can’t just ignore threats to animals headed for extinction,” said Marc Fink, a senior attorney at the Center for Biological Diversity. “This massive mine would wipe out more than a thousand acres of forest critical to the survival of the Canada lynx, whose paw prints have been found at the mine site. Mining has already fragmented wildlife habitat, and threatened animals like lynx won’t survive if their home is turned into an industrial mining zone.”

The lawsuit challenges the Fish and Wildlife Service’s 2016 biological opinion, which concluded that thousands of acres of permanent habitat destruction wouldn’t harm the species’ critical habitat. In 2017 the Forest Service relied on that opinion to issue its approval of a land exchange with PolyMet that facilitated the proposed mine. The Clean Water Act permit issued by the Army Corps in 2019 also relied on the Fish and Wildlife opinion.

The lawsuit challenges those agency decisions, as well as the failure of the Army Corps and Fish and Wildlife to reconsider their actions in light of new information and changes to the project.

“The U.S. Forest Service is handing over part of our national forests to a foreign company to build an enormous open-pit copper mine in the headwaters of Lake Superior,” said Lori Andresen with Save Our Sky Blue Waters. “Great Lakes communities and endangered species don't want and don't deserve the destruction, fragmentation and toxic sulfide mine waste that the PolyMet mine would generate.”

The PolyMet mine would destroy nearly 4,000 acres of habitat for lynx and other wildlife — including 1,719 acres at the proposed mine site — with open-pit mines, waste rock stockpiles and mining infrastructure. Most of the destruction would be permanent.

Open-pit copper mining is not allowed in the Superior National Forest because it ruins irreplaceable natural resources. But rather than reject the mine and protect the forest, the Forest Service instead agreed to trade this publicly owned land to PolyMet so the proposed copper mine could proceed.

“The destruction of wetlands and forests would harm many species of animals and plants, and key migration corridors in this region face growing threats from mining and potential mine expansion,” said Elanne Palcich with the Save Lake Superior Association. “The lynx and northern long-eared bat are like canaries in the coal mine, telling us that we must take action to protect what’s left before it’s too late.”

In addition to wiping out lynx and northern long-eared bat habitat, the mine would destroy high-quality wetlands and risk long-term, toxic water pollution in the Lake Superior watershed.

“The proposed construction of a massive open-pit copper mine at the headwaters of the St. Louis River threatens Lake Superior, Duluth and other downstream communities, as well as imperiled wildlife that depend on our remaining forests, wetlands and clean water,” said Libby Bent with Duluth for Clean Water.

The Endangered Species Act requires federal agencies to ensure that proposed actions will not destroy or adversely modify critical habitat for threatened and endangered species. The Fish and Wildlife Service’s biological opinion for PolyMet determined that the mine would destroy more than 1,700 acres of critical habitat for Canada lynx.

The Fish and Wildlife Service has designated Minnesota as one of the few core areas for Canada lynx, and most lynx habitat in the state is in the Superior National Forest. Northeastern Minnesota is the only area in the Great Lakes region with evidence of recent lynx reproduction. Lynx tracks have been observed on the proposed PolyMet mine site.

The northern long-eared bat was listed as a threatened species in 2015. The bat’s population in the state has been devastated by white-nosed syndrome.

The proposed mine would also permanently destroy critical habitat for the gray wolf. While wolves were delisted from the Endangered Species Act in 2020, the Center and other organizations are challenging that delisting in court.

The plaintiffs in the lawsuit are the Center for Biological Diversity, Save Lake Superior Association, Save Our Sky Blue Waters, Friends of the Cloquet Valley State Forest, and Duluth for Clean Water.