Why it matters: A lawsuit revealed the Minnesota Pollution Control Agency quashed information from the EPA that copper-nickel mining could pose a threat to the environment near Lake Superior and tribal lands.

The biggest threat to establishing a copper nickel mine in northern Minnesota may not be the opposition of environmentalists as much as an eroding public trust in the process of approving the project.

The credibility of the permitting process was damaged when the Minnesota Supreme Court ruled the state improperly issued a permit after a lawsuit showed the MPCA had quashed an Environmental Protection Agency report that cast doubt on the environmental safety of the project.

The Supreme Court ruling against the MPCA said the agency was wrong to issue permits to the project and was contrary to the “express purposes” of the Administrative Procedure Act, which is designed to provide public transparency on such projects. The lawsuit filed against the project by the nonprofit WaterLegacy and the Fond du Lac Band of Lake Superior Chippewa through court discovery and freedom of information requests unearthed the EPA document never before published.

The EPA said it wasn’t sure the permit was stringent enough to meet federal Clean Water Act standards and other federal regulations. MPCA responded that the EPA never offered comments during the public comment period.

The court’s 6-0 ruling was filed in two opinions. One, written by Justice Anne McKeig, said the “secrecy is unacceptable” and the MPCA deception “continued the country’s centuries-long history of threatening tribal resources with political disregard for tribal rights.”

The copper-nickel mine — once known as PolyMet but now renamed NewRange Copper Nickel — would be located upstream from tribal lands and would be the first such mine in Minnesota. Environmentalists say the mine would unearth sulfuric acid and other pollutants as the copper and nickel are surrounded in the ground by sulfide minerals.

The U.S. Army Corps of Engineers in June revoked a water quality permit for the project. It said the project did not meet water quality standards set by the Fond du Lac Band, whose reservation is on the St. Louis River downstream from the mine and its processing sites.

The hiding of documents and politics of mining might be considered business as usual, but Minnesotans should thank the plaintiffs for challenging the permit. Their diligence stopped this corruption. Minnesota’s pristine land and waters are too valuable to be sullied by bad politics and policy.

MPCA and EPA leaders were wrong to keep secret the damning information on water pollution threats. Their actions have hurt the credibility of the process. The public now has a right to be skeptical of the project.