The Minnesota Court of Appeals has suspended more permits for PolyMet Mining’s proposed $1 billion copper-nickel mine, pending a court hearing next month.

The temporary stays affect the company’s permit to mine and two dam-safety permits, all issued last year by the state Department of Natural Resources (DNR) and opposed by environmental groups and the Fond du Lac Band of Lake Superior Chippewa.

The move is another win for the environmental groups challenging what would be the state’s first copper-nickel mine, although it remains to be seen how it affects progress on the divisive project. PolyMet has been moving toward construction.

The order, out Wednesday, also instructs the DNR to advise the court at an Oct. 23 hearing on two matters: whether PolyMet’s new majority owner, Glencore, will be included on the permits; and what the DNR learned from its review of the failure of a mine waste dam that collapsed in Brazil earlier this year.

The DNR has not given the court enough information about either matter, Chief Judge Edward Cleary said in the order.

Opponents “raise serious, justifiable concerns about the ongoing regulation of the NorthMet project,” he wrote, and said that post-permit developments require close review and the appropriate action “by the DNR and other permitting authorities.”

The state Appeals Court has already suspended PolyMet’s water quality permit pending a Ramsey County District Court hearing into alleged “irregularities” in how the Minnesota Pollution Control Agency handled that permit.

That hearing hasn’t been scheduled yet. Two other investigations into the handling of the water permit are underway.

Opponents say the state hasn’t adequately addressed public concerns about opening Minnesota up to copper-nickel mining.

“With three permits suspended and three investigations ongoing, it’s time for Governor Walz to take this matter seriously and tell his DNR to hold public hearings to ensure that Minnesotans are protected,” said Aaron Klemz, spokesman for the Minnesota Center for Environmental Advocacy.

The center represented numerous groups in the appeal, including Friends of the Boundary Waters Wilder­ness, Save Lake Superior Association, Duluth for Clean Water, Center for Biological Diversity, Friends of the Cloquet Valley State Forest and Save Our Sky Blue Waters. The order also applies to a separate action by WaterLegacy, Klemz said.

The Fond du Lac Band of Lake Superior Chippewa also separately appealed the permits, he said.

DNR downplays ruling

Toronto-based PolyMet Mining, now majority owned by Switzerland-based mining conglomerate Glencore, issued a statement expressing disappointment. The DNR has already addressed the questions, it said, adding that the Brumadinho tailings dam that collapsed in Brazil in January was significantly different from the PolyMet tailings dam.

“We are confident that the post-permit questions that led to the temporary stay lack merit,” company spokesman Bruce Richardson said.

The DNR issued a statement downplaying the significance of the court’s move. The suspensions are only temporary, it said, and “intended to provide the court with the opportunity to understand the DNR’s consideration of these issues before work authorized under the Permit to Mine and Dam Safety Permits proceeds.”

The oral arguments had already been scheduled, it noted.

PolyMet said it expects a court decision on the challenges by late January.