Conservations groups sued the U.S. Army Corps of Engineers today to challenge a key water permit authorizing the PolyMet open-pit copper mine to move forward. The mine would destroy 1,000 acres of wetlands and more than 1,700 acres of critical wildlife habitat in northern Minnesota’s Superior National Forest.

“The PolyMet mine would result in the single largest permitted destruction of wetlands in the history of Minnesota,” said Chris Knopf, executive director of Friends of the Boundary Waters Wilderness. “Despite this, as recently revealed documents have shown, federal and state regulators seem to have been hellbent on permitting PolyMet. This is another example of how our federal and state regulators are violating the law to rig the process in favor of a foreign mining conglomerate with a terrible history of environmental devastation around the world.”

Today’s lawsuit, filed in U.S. District Court in Minneapolis, says the Corps violated the Clean Water Act and the National Environmental Policy Act when it issued the permit in March.

PolyMet’s proposed copper-sulfide mine would be located at the headwaters of Lake Superior, upstream from the St. Louis River, the largest U.S. tributary to Lake Superior, as well as the Fond du Lac Reservation and the city of Duluth. These pristine wetlands are a primary source of freshwater to Lake Superior, the largest freshwater lake in the world, and were set aside by Congress for federal protection.

“The wetlands that PolyMet would destroy sequester millions of tons of greenhouse gases, are critical habitat for threatened species, and have been designated as an area of high biodiversity significance,” said Kathryn Hoffman, chief executive officer of the Minnesota Center for Environmental Advocacy. “In addition to digging up 900 acres of wetlands, Glencore’s proposed PolyMet mine threatens to drain thousands of additional acres. Once these wetlands are destroyed, they can never be repaired.” 

The Corps’ permit to PolyMet under the Clean Water Act was the largest permitted destruction of wetlands in Minnesota’s history. The wetlands permit is the last permit required before the mining company can begin construction.

“It’s reckless for the Corps to allow massive wetlands destruction in the precious headwaters of Lake Superior,” said Marc Fink, a senior attorney at the Center for Biological Diversity. “They’re putting public health and the environment at risk. They’re endangering Minnesota’s declining moose population, water quality, and downstream communities. This toxic mine could poison the region for generations to come.”

Scientific experts say the PolyMet mine could increase releases of methylmercury, a neurotoxin, resulting from pollution and hydrologic changes to the wetlands. This threatens public health and wildlife, including fish, moose, and wolves.

The Fond du Lac Band of the Minnesota Chippewa Tribe also filed a complaint today, also challenging the wetlands permit issued by the Army Corps.

“Congress enacted the Clean Water Act to restore and maintain waters of the United States. The Corps’ decision does the opposite — degrading pristine wetlands and contaminating local rivers that form the headwaters to a major source of drinking water for millions of people. Federal law prohibits such an outcome,” said Jaimini Parekh, an attorney with Earthjustice, which is representing the plaintiffs.

The groups challenging the permit are Friends of the Boundary Waters Wilderness, Minnesota Center for Environmental Advocacy and the Center for Biological Diversity.