Mining and phosphorus processing company P4 Production has agreed to pay a $1.4m civil penalty to the Department of Justice and the Environmental Protection Agency (EPA) for alleged Clean Water Act violations at its South Rasmussen Mine in Idaho, US.

P4 has also agreed to spend an estimated $875,000 on monitoring and to prevent pollutants from entering local waters.

According to the complaint, the company allegedly discharged wastewater containing high concentrations of selenium and heavy metals from a waste rock dump at the mine without a required permit.

Further, P4’s unpermitted discharges allegedly polluted a nearby wetland and an unnamed tributary of Sheep Creek, as well as downstream waters that drain to the Snake River.

Under the consent decree, the company agrees to continue collecting selenium-contaminated leachate from the waste rock pile and prevent those from entering nearby creeks and wetlands until such time as the company either obtains an NPDES permit, or it undertakes a restoration of the waste rock dump under another state or federal order, EPA said.

The company also agrees to perform downstream monitoring for a period of five years to ensure that selenium-contaminated water is no longer leaving the site.