Three environmental groups filed a petition Tuesday asking the Minnesota DNR for a "contested case hearing" on the proposed PolyMet mine, before the agency decides whether to grant the project final approval.
The Minnesota Center for Environmental Advocacy, the Center for Biological Diversity and the Friends of the Boundary Waters Wilderness submitted the petition, along with six expert reports that question certain aspects of PolyMet's mining proposal.
A contested case hearing is a trial-like process, held before an administrative law judge, and would include testimony, evidence and cross-examination.
The judge would then issue a recommendation to the DNR, before the agency commissioner decides whether to ultimately approve the mine.
The process is common in Minnesota for large development projects. For example, an administrative law judge held several days of hearings for the Line 3 oil pipeline currently under consideration by the Minnesota Public Utilities Commission, and is currently preparing her report.
The conservation groups say the hearings are needed to settle disputes over issues such as the tailings dam designed to hold back PolyMet's mine waste.
Aaron Klemz with the Minnesota Center for Environmental Advocacy said "It's particularly critical in this case because of how complex" the project is, "and the potential impact this project could have on downstream users and downstream waters."
"And so we think it's particularly important in this case to use this process to make sure all the facts are on the table before a decision gets made," he said.
But PolyMet argues the project has already undergone the longest and most comprehensive environmental review ever conducted in Minnesota.
• In Duluth: More opposition to Polymet mine
"The same thoroughness that went into the environmental review was applied in the preparation and drafting of the permits, which also have been open to public review and comment," said company spokesman Bruce Richardson.
Conservation groups and politicians in Duluth have also asked for a contested case hearing for the past two years, before state regulators make final decisions on PolyMet.
The DNR has 90 days to respond to the petition.
Meanwhile, the public still has until March 6 to comment on the PolyMet draft permit to mine.