Knife River Materials fined by MPCA for industrial wastewater violations

The MPCA fined Bemidji-based Knife River Materials for violating rules related to discharging mine pit water into public bodies of water.

Minnesota Pollution Control Agency web art

BEMIDJI -- Knife River Materials has paid a civil penalty of more than $17,000 to the Minnesota Pollution Control Agency.

The Bemidji company was penalized for industrial wastewater violations at a nonmetallic aggregate mining facility near Mentor, Minn., according to a press release. The company also submitted a plan for meeting its permit requirements, including instituting best management practices, installing floating silt curtains and earthen berms in its mine pit, and settling basins.

In total, Knife River was fined $17,525 after MPCA staff confirmed that sediment-laden mine pit water had been discharged into Lower Badger Creek and a nearby ditch. For 18 days, the company discharged dredged mine pit water to surface water, which is not permitted, and then installed berms to stop the discharge.

The company's discharges also exceeded permitted limits and caused nuisance conditions in surface waters. Additionally, the company didn't report the problems to either the Minnesota State Deputy Officer or the MPCA, which is required. Knife River also failed to recover the sediment that had left the site.

The MPCA required the company to stop discharging the mine pit water directly into surface water at all of its sites. The company also had to submit a procedure for how to report and respond to discharges that exceed permit limits.


The MPCA calculates penalties by taking into account how seriously the violations affected or could have affected the environment, whether they were first-time or repeat violations, and how promptly the violations were reported to authorities. The agency also attempts to recover the economic benefit the company gained by failing to comply with environmental laws in a timely manner, the release stated.

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