The Minnesota Pollution Control Agency will not support U.S. Steel’s request to reclassify portions of the Dark River, which sits at the foot of the company’s Minntac tailings basin, unless the mining and steel-making company can provide the agency with more information.

In a July 31 petition, U.S. Steel asked the MPCA to consider removing the industrial-use and agriculture-use standards for portions of Upper Dark River, Timber Creek and Dark Lake.

The existing industrial-use standard holds the water to specific pH, hardness and chloride standards while the agricultural-use standard regulates specific conductivity, total dissolved salts, boron, bicarbonate, sodium and pH.

In past court documents, the MPCA has said Minntac’s leaking tailings basin is leading to elevated levels of many of those chemicals in nearby waters.

In its petition, U.S. Steel argued the agricultural and industrial uses did not exist in those waters, and that the bodies of water should be reclassified.

But the MPCA disagreed.

"The MPCA has reviewed the petition and finds that at this time it does not support a review of the designated uses,” Catherine Neuschler, manager of the MPCA’s water assessment section, wrote in a Sept. 30 letter to U.S. Steel, noting U.S. Steel's petition ”does not adequately demonstrate” that industrial use is not an existing use of the water and that the company “does not show that downstream standards will be protected” if agricultural water-quality standards are removed.

The move does not reject the petition, which remains under consideration by the MPCA. Instead, it asks U.S. Steel to provide more information to prove the water isn't used for industry.

However, it indicates the MPCA will not still consider removing the water's classification for agricultural use because that would not protect downstream waters.

U.S. Steel made a similar reclassification petition for the Dark River in August 2018, asking the MPCA to remove Dark River’s drinking water, industry, agriculture and trout stream designations. A letter sent by Neuschler of the MPCA in October 2018 said the evidence submitted by U.S. Steel “supports the requested review of the designated use,” but the letter sent last week indicated the agency would not reconsider the agricultural use designation in either permit because of its inability to show downstream waters would be protected.

“The MPCA will not be further considering that portion of the prior petition,” Neuschler wrote.

In an emailed statement to the News Tribune Tuesday, a U.S. Steel spokesperson said the removal of those use classifications would not be harmful.

"Removal of uses that do not exist will have no impact to the existing water bodies or downstream waters – similar to removing a school zone speed limit from a road that does not have a school,” U.S. Steel said.

Minntac, U.S. Steel’s massive Minntac taconite iron ore processing center in Mountain Iron, has an 8,000-acre tailings basin that leaks into nearby surface and groundwater. Treated water from the tailings basin is also discharged into the Dark River.

The 12-square-mile tailings basin is the dammed-up holding pond for the wet slurry of mine waste left after taconite pellets are processed.

But the MPCA has acknowledged in the past that the leaking tailings basin has long led to higher levels of chemicals than state standards.

In early 2017 the MPCA filed a 33-page response to a lawsuit by U.S. Steel alleging MPCA was stalling on issuing the permit, saying the company had regularly violated agreements with the state to reduce pollutants even as nearby waters showed ever-higher levels of problem substances. The state response blamed the Minntac operations and pollution seeping out of its tailings basin for pollution of nearby waters.

"Since the tailings basin was permitted, concentration of sulfate and other dissolved elements have increased in the groundwater around the tailings basin," the MPCA said in the court document, also noting that the Dark River, Sandy River, Sandy Lake and Little Sandy Lake then exceeded some standards for sulfate, bicarbonate, hardness and total dissolved solids "because of polluted groundwater from the tailings basin is entering those surface waters."

Late last year, the MPCA issued Minntac its first discharged permit since 1987, and set firm deadlines for the facility to meet state and federal regulations already in the books.

MPCA spokesperson Lucie Amundsen said that if any of the uses along the Dark River or other surrounding waters were to be reclassified, it would not change the conditions of the permit.

“As long as the permit stands, the discharge limits in it would not change. The permit would have to be revised in order to change the discharge limits, and information about those changes would be provided in a permit application,” Amundsen said. “The discharge limits in the permit are for sulfate and are there to protect groundwater, which will continue to be protected at the same level. U.S. Steel will have to continue to work to meet those standards for their discharge, which require working towards a sulfate limit of less than 357 milligrams per liter for the tailings basin and less than 250 milligrams per liter in the groundwater when it leaves the property boundaries.”