Northshore Mining Co. operates a taconite processing plant and tailings basin in Silver Bay, which receives ore from the company's Peter Mitchell Mine. The Peter Mitchell Mine is a separate facility with its own permits.
Our role
The MPCA is responsible for issuing and enforcing permits that limit air emissions and water discharge from Northshore Mining’s operations to protect the environment and health of Minnesotans. Those permits reflect current state laws and regulations.
The MPCA received an updated wastewater permit application from Northshore in April 2021 and has drafted a permit that covers the facility and its tailings basin at Mile Post 7, located about four miles inland from the processing plant.
Project information
At Silver Bay, the coarse taconite ore is cobbed, crushed, and concentrated, then sent to the pelletizing plant, where it is formed into green pellets, fired in furnaces, stockpiled, and loaded for ship transport.
Pollutants of concern from this facility include particulates from the primary ore crusher, which are controlled by a fabric filter, and products from combustion such as nitrogen oxides and carbon monoxide. Wind and human activity at the facility also produce airborne particulate matter known as fugitive dust, which comes from sources such as trucks hauling materials and material stockpiles.
Waste from the processing plant is sent to the Mile Post 7 tailings basin for disposal.
Next steps and timeline
The MPCA will schedule and host public informational meetings during the upcoming public comment period for the draft wastewater permit. After the public comment period, the MPCA will consider comments, revise the permit if necessary, and finalize it. The MPCA expects to issue a final wastewater permit for the facility in 2025.