The Minnesota Court of Appeals has ordered state regulators to rework a long-awaited pollution permit related to a leaking 1960s-era Iron Range taconite tailings basin, saying it might need tougher standards to protect local waters.
The decision, issued Monday, kicks the contentious permit back to the Minnesota Pollution Control Agency (MPCA), which issued the updated version last year after allowing the facility to operate for more than two decades with an expired, temporary permit.
The basin holds mining waste from Minntac's mine in Mountain Iron, which is owned by Pittsburgh-based U.S. Steel Corp. and is the country's largest taconite operation.
At issue are pollutants — primarily the mining byproduct sulfate — leaking into nearby waters from Minntac's 13-square-mile, unlined basin.
The updated water quality permit called for U.S. Steel to reduce sulfate in the basin within 10 years and install a collection system to capture and return contaminants leaking out of the western side of the basin.
U.S. Steel appealed the permit because the MPCA denied its request for a variance from groundwater-quality standards, and also denied its request to hold a contested-case hearing.
The Fond du Lac Band of Lake Superior Chippewa and the environmental group WaterLegacy separately appealed, arguing that the contaminants seeping out into surface water — directly and through groundwater — were violating water quality standards, decimating downstream wild rice and worsening mercury contamination of fish.
The appeals were bundled. And in a complicated decision, state Appeals Court Judge Jeanne M. Cochran found that the MPCA did not err when it concluded that the federal Clean Water Act doesn't govern industrial discharges into groundwater. The law is ambiguous, and the agency's interpretation was reasonable, she said.