US Steel Corp - Minnesota Ore Operations Keetac Tailings Basin and Mining Area - Wastewater Permit

We invite you to comment on the draft wastewater permit for the the US Steel Minnesota Ore Operations Keetac Mining Area and Tailings Basin.

The Keetac Mining Area and Tailings Basin is located near the city of Keewatin in St. Louis and Itasca Counties. The principal activity at this facility is the open pit mining of taconite for processing into taconite pellets. United States Steel Corporation’s (U. S. Steel’s) Minnesota Ore Operations - Keetac facility (Keetac) is currently regulated by two National Pollutant Discharge Elimination System (NPDES) / State Disposal System (SDS) permits. MN0031879 currently covers discharges to surface waters for the Mining Area (Mining Area Permit); and MN0055948 covers discharges associated with the Tailings Basin (Tailings Basin Permit). This permit action combines the existing NPDES/SDS permits for the Keetac Mine Area and the Keetac Tailings Basin into one NPDES/SDS permit to be identified as MN0072338.

The draft permit regulates industrial wastewater discharges from the tailings basin, mine pit dewatering, and plant site and stockpile runoff. All of the permitted discharges ultimately flow to Hay Lake. The draft permit contains a compliance schedule for the facility’s discharges to meet final effluent limits for sulfate by Dec. 31, 2036.

Wastewater from industrial and commercial sources may contain pollutants at levels that could adversely affect the water quality in area wetlands, streams, rivers, and lakes. Water quality permits - or National Pollutant Discharge Elimination System (NPDES) permits - establish specific limits and requirements to protect Minnesota's surface and groundwater quality. All wastewater must be treated before it goes into surface water to protect human health and aquatic life. Permits are regularly reviewed and updated as they expire, allowing the MPCA to incorporate new information about the impacts of pollutants on the environment in future permits.