Several Minnesota environmental groups asked state agencies to suspend permits for the contentious PolyMet copper-nickel mine in Minnesota.

The Minnesota Center for Environmental Advocacy, WaterLegacy and Friends of the Boundary Waters Wilderness submitted a request for stay, or suspension, of permits issued by the Minnesota Department of Natural Resources last week and pending permits from the Minnesota Pollution Control Agency until the Minnesota Court of Appeals rules on whether an additional environment review of the project is needed.

Before the groups can ask the Court of Appeals for a stay on the permits, they're required to first request a stay of permits from the agencies themselves, WaterLegacy counsel and advocacy director Paula Maccabee told the News Tribune on Thursday.

"It's not like this is the endgame, but it is a preliminary step," Maccabee said.

While the DNR granted the permit to mine and 10 other approvals to PolyMet last week, it was based on the company recovering about 32,000 tons of ore every day. Environmental groups argue a report released by PolyMet in March outlines the company's ambitions to triple that to 118,000 tons per day and that the impacts of that larger project must be factored into the environmental review.

"PolyMet's permits are based on a bait-and-switch," Aaron Klemz of the Minnesota Center for Environmental Advocacy said in a statement Thursday. "PolyMet didn't show their hand on its larger mine plan until March 2018, when it was too late for the public to comment on it. The DNR and (Minnesota Pollution Control Agency) must analyze the environmental harms posed by PolyMet's larger and even riskier mega-mine plan."

However, DNR Commissioner Tom Landwehr disagreed with that argument in a press conference last week announcing the agency's permit decisions. He said if any changes like those outlined in the March report were officially proposed by PolyMet, another environmental review and permitting process would need to be conducted.

"It is not a bait and switch. It is a proposed project that's been permitted. Any significant changes need to go through the same permitting process," Landwehr said.

The PolyMet environmental review was released in November 2015 and the DNR determined it was "adequate" in March 2016. In July and August, the DNR rejected petitions by several environmental groups calling for additional environmental impact statements to consider the March report's potential project expansion.

In an email to the News Tribune on Thursday, PolyMet spokesperson Bruce Richardson responded to the environmental group's petition to suspend permits and denied any additional proposals.

"The final permits we received from the state last week and those currently pending final decisions are based on a mine plan that was the subject of a 14-year-long environmental review and permitting process, and which we plan to build. We have no other mine proposals. Beyond that, we will not comment further since this is the subject of active litigation," Richardson said.

The open-pit mine, first officially proposed in 2004 though under consideration since 1999, would refurbish part of the LTV Steel plant and produce millions of tons of copper, nickel, cobalt and other metals annually. It is the first such mine to be approved in the state.

Critics say the project is likely to send tainted runoff into local waterways, potentially polluting the St. Louis River system. Supporters say the 300 jobs at the mine will help diversify the regional economy.

The project still needs, at the very least, water and air quality permits from the Minnesota Pollution Control Agency and a wetlands permit from the Army Corps of Engineers before construction can begin.