The PolyMet NorthMet open pit copper-nickel mine would be Minnesota’s first non-ferrous mine. It would include three new open pits, permanent and temporary waste rock heaps, and a permanent tailings waste dump and highly toxic hydrometallurgical residue in Minnesota’s St. Louis River watershed in the Lake Superior Basin.

The PolyMet mine project would be sited on a particularly bad location for a sulfide mine: 

  • Headwaters of the St. Louis River, the largest U.S. tributary to Lake Superior.
  • Wetlands, peatlands and streams in the Lake Superior Basin.
  • Upstream of drinking water, Fond du Lac reservation, city of Duluth, and estuary where the St. Louis River meets Lake Superior.
  • Ojibwe/Chippewa Ceded Territories. 


The PolyMet site and other proposed sulfide mines would be located in 1854 Ceded Territories, and the Fond du Lac Reservation is located on the St. Louis River downstream of the proposed PolyMet mine.

The PolyMet mine project would destroy or impair more than 1,000 acres of wetlands and demand a massive appropriation of water from the St. Louis River headwaters. The PolyMet tailings waste and hydrometallurgical waste dams create an unacceptable risk of failure, threatening downstream waters with toxic pollution.

The PolyMet mine would be located on what is now Superior National Forest land and would require a land exchange of 6,650 acres of High Biological Diversity lands on which Indian tribes have rights to hunt, fish and gather reserved under treaties. The PolyMet project would harm endangered and listed species and would conflict with federal fiduciary responsibilities to tribes as well as state and federal statutes, regulations and policies.

The PolyMet mine site is NOT a “brownfield” site. 




What Do We Know About Sulfide Mining In A Water-Rich Environment? 

Across the country, there is no example where a sulfide mine has been operated and closed in a water-rich environment (like that in Northern Minnesota) without polluting surface and/or groundwater with acid mine drainage, sulfuric acid and/or toxic metals.

This is a striking 100% failure rate in protecting clean water.


PolyMet Proposed Sulfide Mine Basic Facts:

- Proposed length of mine operations: 20 years.
- Duration of pollution from mine pits and other permanent contaminant sources: perpetual.
- Waste rock removed over 20 years: 308 million tons.
- Percentage of waste, including waste rock and tailings waste: more than 99%.
- Contaminated seepage from tailings: more than 2 billion gallons per year.
- Unlined permanent tailing waste facility; 4 ½ square miles. Unlined permanent waste rock pile: 526 acres.
- Wetland acres direct destroyed: 913.8 acres.
- Potential indirect wetlands impacts: 7,694 acres. Proposed wetlands mitigation for indirect wetlands effects: 100 acres.
- Wetlands destroyed/degraded by mine site dewatering calculated by tribal scientists: 5,720 acres.
- Largest wetlands destruction ever approved by the St. Paul District of the U.S. Army Corps of Engineers since enactment of the Clean Water Act.
- Appropriation of 6.175 billion gallons of water per year, equivalent to 85% of entire water use of Duluth water utility.
- Threat of catastrophic tailings dam failure due to unstable foundation, wet slurry. Least cost; not best available technology. 



Mount Polley, British Columbia, Canada sulfide mine catastrophic tailings dam failure in 2014 released 6.3 billion gallons of contaminated tailings water and slurry. Read more about the Mount Polley tailings dam collapse





  • WaterLegacy lawsuit in federal court challenging the PolyMet land exchange as a “sweetheart” deal for PolyMet in violation of federal law is pending. 
  • PolyMet has applied for permits for water appropriations and construction of tailings and hydrometallurgical waste dams as well as a permit to mine from the Minnesota Department of Natural Resources (DNR). READ HERE to learn more about the DNR permitting process. 
  • PolyMet has applied to the Minnesota Pollution Control Agency (MPCA) for water pollution, air pollution and other permits.
  • PolyMet has applied to the U.S. Army Corps of Engineers for a wetlands destruction permit under Section 404 of the Clean Water Act.
  • The MPCA and the Fond du Lac Band government will have the opportunity to evaluate whether the plan complies with Clean Water Act (Section 401) requirements.
  • The DNR has decided that PolyMet’s final environmental impact statement is adequate, but the Army Corps has not made a determination. 
  • All PolyMet agency decisions must comply with applicable state and/or federal law. Barring legislative interference, these decisions may be reviewed its in the courts to determine whether  legal requirements have been met.


  • READ and become informed about the PolyMet project. 

  • Support WaterLegacy and help us develop the expert and legal resources needed for the administrative permitting process and for possible litigation. Your involvement is critical to protect Minnesota clean water from sulfide mining pollution.

  • FOLLOW WaterLegacy on Facebook and TAKE ACTION to protect Minnesota’s water resources and the communities who rely on them. 

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