Cleveland-Cliffs agreed to pay a $50,000 penalty for air quality violations at its United Taconite processing facility in Forbes, where, as part of the settlement, the mining company is also spending nearly $489,000 on new pollution-control equipment.

The U.S. Department of Justice alleged in a complaint filed in U.S. District Court in Minnesota last week that Cliffs "caused or allowed emissions of particulate matter from one or both of its indurating furnaces to exceed the emission limits" at least 13 times between January 2012 and June 2015. Indurating furnaces bake and harden the processed iron ore pellets.

The complaint also claimed Cliffs incorrectly operated pollution-control equipment outside of daily pressure-drop and water-flow limits outside on at least 700 days from 2010 to 2016 and did not use pollution-control equipment when operating processing equipment for 1,500 hours during that same time period.

In a consent decree filed Thursday, federal prosecutors said the Environmental Protection Agency issued Cliffs a notice of air-emissions violations in February 2014.

Cliffs spokesperson Patricia Persico said the issues leading to the alleged violations were corrected "years ago."

"These are old alleged violations dating back more than five years," Persico said. "But they're largely administrative in nature, and related to past record keeping for our dust collection equipment and the iron ore pellet furnaces."

Persico said United Taconite constantly monitors and records the pollution equipment at its facilities, and "we routinely self report potential exceedances of its environmental controls and the system is setup to tend towards more of a conservstive over reporting as a precautionary measure. So if something deviates, it's going to flag."

As part of its settlement, Cliffs will spend $489,000 to replace its wet scrubber control system, which removes pollutants in exhaust air, with a more efficient dry scrubber system.

In 2016, United Taconite agreed to pay a $50,000 penalty to the Minnesota Pollution Control Agency for alleged air-quality violations at its taconite processing plant in Forbes.

At the time, the PCA reports that dust from the plant impacted nearby residents' homes more than 12 times between early 2013 and mid-2015.