Minnesota Supreme Court sides with water-quality regulators on Iron Range mine permit

The Minnesota Supreme Court on Wednesday said state regulators correctly applied drinking-water standards to groundwater when issuing a permit to an Iron Range mine in 2018.

The decision reverses a 2019 Minnesota Court of Appeals decision that said the Minnesota Pollution Control Agency failed in interpreting state water-quality rules in its 2018 permit to U.S. Steel’s Minntac iron ore mine and pellet plant.

The lower court said at the time that drinking-water standards do not apply to groundwater and, therefore, the MPCA couldn’t issue permits with conditions setting groundwater as that class of drinking water.

But in an opinion issued Wednesday morning, Justice Paul Thissen countered the lower court’s opinion.

“We hold that groundwater is a Class 1 water and that the MPCA properly exercised its authority in applying the Class 1 secondary drinking water standards to the 2018 Permit, including the 250 mg/L sulfate standard,” Thissen wrote.

The Minnesota Pollution Control Agency, Fond du Lac Band of Lake Superior Chippewa and environmental group WaterLegacy had argued for such an outcome.

In separate news releases Wednesday afternoon, both the band and WaterLegacy called the decision a win.

“We are gratified to see the Court’s decision today. This success is hard-won, and it is just one step in our fight to protect our wild rice waters,” Fond du Lac Chariman Kevin Dupuis said.

Paula Maccabee, advocacy director and counsel for WaterLegacy, said the decision was “a big win for Minnesota groundwater and for public health.”

“Drinking water standards may now be enforced to control U.S. Steel’s Minntac tailings basin pollution, and U.S. Steel is not above the law,” Maccabee said.

The MPCA had said many of its existing permits had applied drinking-water standards to groundwater, and had the lower court’s decision stood, all of those permits would have been called into question.

“The Minnesota Supreme Court provided needed clarity regarding the MPCA’s ability to protect the state’s drinking waters that include groundwaters,” MPCA spokesperson Darin Broton said in a statement Wednesday.

U.S. Steel, however, supported the lower court’s 2019 decision.

During oral arguments in November, U.S. Steel attorney Jeremy Greenhouse said the Court of Appeals had gotten it right and said stiffer groundwater-as-drinking-water rules were “erroneous” and “would require U.S. Steel to construct and operate an outsize water treatment plant.”

In an emailed statement Wednesday, the company said it was reviewing the Supreme Court’s decision.

The sides had disagreed over whether two different rules, when read together, actually classify groundwater as Class 1 water, or drinking water, which has more stringent requirements, and whether the MPCA has authority over the waters.

The groundwater as drinking-water rules came in a water pollution discharge permit issued by the MPCA in late 2018, the first for Minntac since 1987. While the 1987 permit had been up for reissuance since 1992, the MPCA had administratively extended it for 26 years.

The five-year permit issued in 2018 had set long-range goals for U.S. Steel to meet for reducing pollutants, like sulfates, that are leaking out of the site’s 8,000-acre tailings basin — where a wet slurry of mine waste left over after taconite pellets are processed resides — into nearby surface and groundwater.

High levels of sulfate are known to spur sulfides, which are harmful to wild rice in many waters. Past testing showed Minntac emitting sulfate levels as high as 1,320 milligrams per liter, with an average of 954 milligrams per liter.

The permit requires Minntac reduce sulfate levels within its basin to 800 mg/L within five years and 357 mg/L within 10 years.

The permit requires groundwater and streams surrounding the basin to drop to 250 mg/L by the end of 2025.

While the Fond du Lac Band considered Wednesday’s decision a win, it expressed concern the permit’s use of the 250 mg/L sulfate limit wasn’t low enough to protect wild rice waters in the 1854 Ceded Territory. The band said the permit’s sulfate limit should be lowered to 10 mg/L, the standard for wild rice waters.

“The new Minntac permit ignored the 10 mg/L sulfate limit for these waters, among many other defects, and did little to cause Minntac to remediate existing pollution or curb future discharges,” the band said in its release.

The MPCA stood by the permit it issued Minntac.

“The Court reaffirmed the MPCA had the authority to require federal sulfate limits in the permit issued to MinnTac in 2018,” Broton said. “The agency encourages MinnTac to make meaningful progress in reducing its sulfate discharges while the Court of Appeals addresses the remaining matters in the legal challenge.”

The Supreme Court sent the issue of whether the MPCA was right to deny U.S. Steel’s request for a contested case hearing on the permit and a variance from certain groundwater standards in permit back to the Court of Appeals for consideration.

Minntac is the largest taconite iron ore mining and processing operation in the U.S. In 2019, it shipped 12.9 million tons of pellets and employed 1,460 people. It went online in 1967.

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