MEMO: Protecting the Boundary Waters: Debunking myths about the proposed Twin Metals mine in the headwaters of the Boundary Waters

MYTH: “We can do it safely.” Twin Metals will meet concerns about safe mining.

FACT: Copper mining cannot be done safely. 

• Even under current mining regulations, hardrock mines across the world (including the United States and Canada) are consistently polluting rivers, lakes, and groundwater.

FACT: Hard rock mines always pollute. 

• FACT: All copper mines built since 1990 have degraded downstream surface water quality, with most also degrading groundwater and exceeding water quality standards or permit limits. Despite stricter permitting and monitoring since 1990, the record shows a consistent pattern: hardrock mining (which includes sulfide-ore copper mining) continues to result in long-term, often irreversible downstream water quality degradation across the U.S., even after a mine has closed.
• FACT: See Modern Mine Study: Water Quality Performance and Predictions at U.S. Mines Permitted Since 1990, which reviews eight hardrock mines across the United States to determine whether U.S. nonferrous hardrock metallic mineral mines permitted under modern mining regulations have degraded the quality of downstream surface waters and/or downgradient groundwaters.

FACT: Existing mines are already polluting the area. 

• FACT: Environmental standards in place are inadequate to protect the Boundary Waters. The science documenting the permanent harm that upstream mining could cause has only become stronger since 2023. Two taconite mines (Peter Mitchell and the dormant Dunka) are currently polluting the Boundary Waters, even though both state and federal law establish an absolute non-degradation standard.
• FACT: Extensive monitoring from 2024 and 2025, like in 2023, shows that sulfate in the waters flowing into the Boundary Waters is more than 50% above background levels. Moreover, a consulting firm’s statistical analysis of the MPCA dataset shows to a greater-than-99% certainty that this pollution originates from these two taconite mines, which, in the process of accessing taconite and iron ore, had to dig through and surface rock from a thin layer of sulfide-ore that was layered atop the taconite-bearing ore. It is these incidental waste piles that are causing an illegal degradation of the Boundary Waters. We, with the Northeastern Minnesotans for Wilderness and Save the Boundary Waters, have urged the Department of Natural Resources (DNR) to acknowledge what the science irrefutably shows: that, notwithstanding an absolute prohibition on polluting the Boundary Waters, two mines, as far away as 34 miles, are degrading water quality in the wilderness.
• Now is the time to stop this pollution and stop the permitting of mines that violate the antidegradation standard for the Boundary Waters.

FACT: Sulfide-ore copper mining is inherently risky.

• FACT: 100% of copper mines experience spills or accidental releases.
• FACT: This type of mining has never been done in Minnesota—and has a track record of pollution wherever it occurs. When sulfide-bearing ore is exposed to air and water, it creates sulfuric acid (essentially battery acid), which can leach toxic metals into surrounding waters.
• FACT: At any pH, mine drainage is damaging - an increase of sulfate in water damages wild rice and plays an important part in the creation of methylmercury, the form of mercury that bioaccumulates in fish tissue and subsequently works its way through the ecosystem. 

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MYTH: Sulfide-ore copper mining near the Boundary Waters will boost the local economy and create American jobs. FACT: A copper mine would be a job killer if it were to pollute.

FACT: Research shows that copper mining here would be a net job killer, threatening up to 22,000 jobs and up to $1.6 billion in annual income.

• FACT: The only peer-reviewed and published economic study of the proposed Twin Metals project showed that the region would enjoy more jobs and income if no copper mining was allowed in the headwaters.
• FACT: Twin Metals has also said that much of its workforce will come from out of state and out of the country. A Twin Metals spokesperson, David Ulrich said, “There’s just not that technical talent base here” for some of those jobs. He said, “We’ve reached out across the world to find some of the premier folks on Earth to come and help us with this project.”
• FACT: Twin Metals’ project labor agreement covers only construction—not long-term operations—and union jobs after the mine is built are not guaranteed. Between 1972 and 2007, copper mining jobs declined by 71%, due to advances in automation and workforce-reducing technologies.
• FACT: A peer-reviewed Harvard University economics study — authored by Prof. James Stock, former chair of Harvard's Economics Dept. and former White House Council of Economic Advisors member — modeled 72 scenarios and found that in 96% of them, protecting the wilderness by banning copper mining in the BWCAW watershed produced greater economic benefit than the Twin Metals mine. The few scenarios that found otherwise were least likely to occur.
• FACT: Statewide, outdoor recreation contributes $13.9 billion annually to Minnesota’s economy—dwarfing the $1.2 billion from extractive industries like mining.

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MYTH: “We have the technology to do it right.” Any pollution from a Twin Metals mine would be contained and manageable.
FACT: The Boundary Waters watershed is uniquely vulnerable.

• FACT: The Boundary Waters is a uniquely water-intensive lakeland wilderness ecosystem characterized by a massively interconnected system of lakes, rivers, streams, and wetlands set in a forested landscape. These waters lack buffering capacity, which leaves them uniquely vulnerable to pollutants.
• FACT: The proposed Twin Metals mine risks triggering acid mine drainage, releasing sulfuric acid, heavy metals, sulfate, and other toxins, along with air, noise, and light pollution. These pollutants would flow through interconnected waterways—spreading from the heart of the Boundary Waters along the international border, into Voyageurs National Park, Quetico Provincial Park, and ultimately Hudson Bay.
  This contamination could persist for decades or even centuries.

FACT: This mining would pose serious risks to human health.

• FACT: Sulfide-ore copper mining releases hazardous pollutants, including sulfuric acid and heavy metals, that are harmful to people and wildlife. This kind of mining releases 6 of the 10 toxins the World Health Organization identifies as most dangerous to human health.
• FACT: Even small amounts of this pollution can have significant public health impacts. Sulfide-ore copper mining would increase mercury contamination in water and in fish tissue, due to the release of additional sulfate. Sulfate plays a key chemical role in the methylation of mercury, which is the form of mercury that bioaccumulates in fish tissue and subsequently works its way into the food chain.
  Increased methylation would cause more methyl mercury to build up in fish—which is a powerful neurotoxin, putting people and wildlife who eat those fish at greater risk.
• FACT: Mercury is already a public health threat; for example, a Minnesota Department of Health study found that one in 10 infants in the nearby Lake Superior region were born with unsafe levels of mercury in their blood, leading to poor neurodevelopment.

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MYTH: We should just "trust our agencies and regulations."
FACT: Minnesota’s rules are insufficient to protect the Boundary Waters.

• FACT: Blind trust is not how environmental protections work. It has happened time and time again: companies and their engineers present a compelling story that the mine could control its pollution and avoid violations of permit limits and water quality standards, and yet once those mines get built, they consistently go on to violate permit limits and water quality standards, despite promises. Systemic problems in environmental review and permitting for mine plans mean environmental review and permitting fail to predict the pollution that actually occurs at mines once they are built. In our watershed, once the pollution has occurred it is too late. That’s why we advocate for a ban on this type of mining.
• FACT: Scrutiny is essential when so much is at risk, and in Minnesota, we have a responsibility to examine whether our state’s rules governing sulfide-ore copper mining are adequate to protect the Boundary Waters. That's why we brought a landmark lawsuit in 2020 challenging Minnesota's outdated rules governing copper mining, arguing that they fail to protect the Boundary Waters and its watershed from the unique pollution risks posed by sulfide-ore copper mining. When clean water is on the line, scrutiny isn't optional—it's essential.

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MYTH: Minnesota's permitting standards are strict enough to protect the Boundary Waters from pollution

FACT: The Boundary Waters Canoe Area Wilderness has a “no degradation” standard, meaning you cannot add any pollution to its waters. 

This standard would be impossible to maintain if a copper mine is established in the headwaters of the Wilderness.
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MYTH: “There is no guarantee minerals from a Twin Metals sulfide-ore copper are going to China - they will mostly go to Canada.”

FACT: Antofagasta sends all of its copper concentrate to China, where it is processed for free.

• In Twin Metals’ 2019 mine plan submission, it had the copper sent offshore. The best evidence is what Antofagasta actually does: it sends all of its copper concentrate to China, where it is processed for free.

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MYTH: The ore body is different in Northeastern Minnesota, and the deposit is too high-grade to leave in the ground.
FACT: It’s low grade.  

• FACT: Australia alone has 83 cobalt deposits, 55 of which are double or higher grade than the Duluth Complex. One Australian deposit alone contains enough cobalt to supply the entire U.S. at current demand for over 270 years. Another currently operating Australian mine has cobalt grades five times better than Twin Metals' best projection. If we need critical minerals, there are better, safer places to get them.
• FACT: Even if every ton of ore were extracted, a Twin Metals mine would meet only about 1.5% of U.S. annual cobalt demand — and that percentage would shrink as demand grows. The MPCA's own former commissioner called it 'barely a bug on the windshield of the global copper market.'

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MYTH: The Twin Metals project would mine the entirety of the Duluth Complex.
FACT: That would be nearly the entire Arrowhead of Minnesota. 

• FACT: The proposed Twin Metals mine would tap just a small portion of the ore in three deposits within the vast Duluth Complex, not the entire resource.
• FACT: The mine plan targets only 6.5% of the ore from just three of those 18 deposits in the vast Duluth Complex. Size and significance do not override location. There are gold deposits in the headwaters of Yellowstone. There is uranium on public lands around the Grand Canyon. We don't mine them because some places are simply off-limits — not because the resources aren't there, but because what we'd destroy to get them is worth more than what we'd extract.

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MYTH: “The Duluth Complex is not acid-generating.”
FACT: The science is clear: the Duluth Complex is definitely acid-generating.

• FACT: For years, Twin Metals has claimed that the Duluth Complex—the ore body it proposes to mine—is not acid-generating. But federal regulators and independent scientists have reached the opposite conclusion. The ore body Twin Metals is proposing to mine is acid-generating.
• FACT: The U.S. Environmental Protection Agency determined that the Duluth Complex is acid-generating, meaning that mining and exposing its sulfide-bearing ore to air and water can produce acid mine drainage and release toxic metals into surrounding waters. Numerous peer-reviewed studies have concluded that a sulfide-ore copper mine in the Boundary Waters watershed would carry a high risk of long-term water pollution.
• FACT: After a two-year scientific review, the U.S. Forest Service concluded in 2016 that a Twin Metals mine would pose an "unacceptable risk" to the Boundary Waters, an "irreplaceable" resource. The agency further found that pollution from such a mine could not be fully mitigated or reversed once it occurred.

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MYTH: “We have never had the opportunity to discuss this, honestly and openly.”
FACT: Wilderness advocates and advocates for copper mining at the doorstep of the Boundary Waters have been having this conversation at the state and federal levels for over a decade.

• FACT: The United States Forest Service and the Bureau of Land Management conducted a thorough and fair process to assess the risk posed by sulfide-ore copper mining in the watershed. They prepared a rigorous NEPA environmental assessment (EA) and prepared 20 different resource reports to analyze all aspects of impact on the environment.
• FACT: The EA was part of the legal process set forth under the Federal Land Management & Policy Act for determining if mining should or should not occur on public lands/minerals.
• FACT: There were public hearings, public input, and scientific review. Twin Metals had the opportunity to submit all that it thought relevant. It had its fair day to present its side of the issue. Since the summer of 2016, there have been:
  • 8 public listening sessions (the majority of commentators, chosen at random, opposed copper mining in the BWCAW watershed in all of the public listening sessions)
  • 454 days for the public to comment.
  • 674,441 people submitted comments to the federal government in favor of protecting the Boundary Waters from copper mining in the headwaters/watershed.
  • FACT: The United States Forest Service and the Bureau of Land Management recommended a 20-year ban based on this thorough and comprehensive Environmental Assessment. Interior Secretary Haaland accepted their recommendation for a 20-year ban and signed a Public Land Order banning mining on federal lands in the Rainy River Headwaters watershed, upstream of the BWCAW.