Stop Sulfide Mining


Minnesotans love Lake Superior, the Boundary Waters, North Shore, and all of Northern Minnesota—and we are deeply concerned about proposals to develop copper/nickel (also called sulfide ore) mining in the region including PolyMet and Twin Metals. Such mining poses a great threat to our Northern communities and environment: There is no safe mining of that type, as tailings (or mining waste) eventually leach into the ground, polluting lakes and rivers. In fact, the Environmental Protection Agency has called sulfide ore mining America’s most toxic industry. 

What We Do

The Sierra Club continues to fight sulfide ore mining and advocate for a just transition away from harmful resource extraction. Our advocacy is focused in the following areas:

  • At the State Legislature: Minnesota’s framework of environmental protections must be defended from any rollbacks, to safeguard our state’s precious resources and the people who depend on them. We are supporting partners in the coalition to pass a Prove it First bill. Every sulfide mine located in a water-rich environment has resulted in pollution of surface or groundwater. Prove it First would prohibit sulfide ore mines until they have been proven safe through long-term operation and closure of similar mines elsewhere. A similar law was in place for two decades in Wisconsin.

  • In the Courts: We have joined other environmental groups in legal challenges to the PolyMet proposal. Minnesotans depend on safeguards to ensure that their health and communities are protected from pollution. Our legal challenges focus on areas where government agencies are falling short in their duties. 

  • At the Federal Level: Through our federal lobby team and nationwide reach we are able to support action by federal agencies, the President and Congress to permanently protect the Boundary Waters Wilderness, Lake Superior and downstream communities. 

  • Through Local Efforts Across the State: We organize community members to spread the word that sulfide mining is not for Minnesota, with actions including letter writing events, film showings, workshops and petitioning.

Get Involved

  • Water & Wetland Stewards. Join the team of folks helping to provide the technical and policy experience needed to stop sulfide mines. (You don’t need to be an expert to join them!)

  • Duluth Team. Join the team of folks in the Duluth region organizing to stop PolyMet and toxic sulfide mines. 

With questions on this team, email Jenna, at 

Past Accomplishments

Since the founding of the North Star Chapter in 1968, Sierra Club volunteers have been actively involved in mining issues within Minnesota: protecting Duluth’s drinking water from asbestos-like fibers in the Reserve Mining case, copper-nickel mining, the expansion of taconite plants and processing facilities, and more recently frac sand mining. A resurgence of high metal prices worldwide has triggered interest from multinational mining companies looking to take advantage of the state’s mineral resources, leading to our current work to stop sulfide mining.

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