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Twin Metals Minnesota Mining in Superior National Forest, USA


In January 2010, Duluth Metals Limited, a Canadian mining company, identified the valuable metal concentrations of the Maturi deposit in Northeastern Minnesota, claiming that the area would be the newest development for the mining industry of the United States [1]. 

There are an estimated four billion tons of copper and nickel within the Maturi deposit, explaining the economic incentive for a mine in the area [2]. Soon after, Antofagasta, a Chilean mining company, collaborated with Duluth Metals Limited, to found Twin Metals Minnesota (TMM). Twin Metals is a subsidiary of Antofagasta, with fifteen Minnesota-based employees that are focused on advancing the proposed mining plan for the Maturi deposit, which is located within the Superior National Forest, and 2-3 miles south from the Boundary Waters Canoe Area Wilderness (BWCA) [1].

Twin Metals aims to develop, construct, and operate an underground mine project that will cover 30,000 acres and be attached to a 100-acre mineral processing facility through one mile of pipeline. The project is nicknamed an “underground city,” as the size of the facility would allow for 20,000 tons of mineralized ore to be processed per day, an amount unprecedented in the Midwestern region of the United States [3]. The mine would also be the first in the area, acting as a gateway project for other mining companies to take advantage of Minnesota’s landscape. Another mining company, PolyMet Mining, is simultaneously pushing to build a facility within the same area. 

Twin Metals claims that the construction of the mine would bring 700 direct full-time jobs and 1,400 spin off jobs for the residents of the nearby towns of Ely and Babbitt [1]. The underground mine would be located nine miles southeast of Ely and eleven miles northeast of Babbitt. Unfortunately, although they are broadcasting that they will bring jobs to the community, TMM will likely negatively affect the local populations. The mine would cause direct water and air pollution, destroy the forest and wetland habitats, and degrade the land that local indigenous populations are promised access to by treaty. Overall, there are numerous reasons for why Twin Metals Minnesota should not be allowed to develop a mine in this region. 

As previously stated, the proposed mine would be in the Boundary Waters of Minnesota. The Boundary Waters cover more than a million acres of lakes and forests that provide a rich habitat for thousands of species. The project’s proposed location is in close proximity to a number of key water bodies, including Birch Lake, the White Iron Chain of Lakes, the South Kawishiwi River, and the Boundary Water Canoe Area Wilderness (BWCA). Even more, the mine would be included within the Rainy River watershed, which drains into the Boundary Waters and Canada’s Hudson Bay, thus threatening a considerably large region of water that populations rely on. The Sierra Club has predicted that a single mine in this area would likely pollute nearby water bodies for at least 500 years [3]. If there were to be any polluted runoff from the site, which is essentially guaranteed considering the size and stature of TMM, then a large volume of water would become contaminated. 

In addition to local water bodies, the copper-nickel mine also poses a great risk to the area’s groundwater. In the same editorial, the Sierra Club claimed that there is currently no sulfide mine in existence that is not polluting groundwater [3]. Hard rock mining carries greater environmental risks because copper is extracted from sulfur-bearing ore that generates toxic sulfuric acid when exposed to oxygen or water [8]. It is likely that the sulfate from the mine will leach into the environment, and therefore become part of the biochemical process in the aquatic and groundwater ecosystems that convert mercury to methylmercury. In turn, this will cause methylmercury, a poisonous heavy metal, to accumulate in the food chain, affecting aquatic life and crops grown in the contaminated soil. 

One group that will be severely affected by the groundwater contamination is the Fond du Lac Band of Lake Superior Chippewa, who is one of the six Chippewa Indian Bands that comprise the Minnesota Chippewa Tribe [4]. Due to the Treaty of 1854, wild rice gathering in the Ceded Territories is guaranteed to the Chippewa (also known as the Ojibwe) and it is a food source that they heavily rely on during its cultivation season [5]. The Ceded Territories include the Rainy River Watershed, which will most likely be polluted by TMM. If the Rainy River Watershed were to be contaminated by the toxic heavy metals from the mine, the wild rice would be harmed by the high level of sulfate in the soil and groundwater. Therefore, the livelihood, health, and food harvesting of the Fond du Lac Band of Chippewa would be wrongfully harmed. 

Another justice issue that is associated with the construction of the Twin Metals mine is the production of mining waste. Less than 1% of the ore extracted from the underground mine would be viable minerals with the remaining 99% being waste rock [3]. In hopes of appearing more environmentally-friendly, Twin Metals released a mining waste plan that they claim is the best available technology in the industry [6]. Their plan involves a dry stack tailings storage method, which involves storing dry tailings in a lined pile underground near the mine’s processing plant. However, the waste would still be stored just a couple miles from the southern edge of the Boundary Waters, within the area’s watershed. The location of the waste is highly problematic considering past examples of tragedies that occurred when similar strategies were used, specifically the disaster that occurred in Brazil when the waste storage of the Córrego de Feijão mine exploded in early 2019, killing nearly 300 people [6]. The explosion released a sludge of muddy mine waste, which swallowed up a section of the local town. Eventually, the waste reached the Paraopeba River, which the locals relied on for the majority of their fish consumption. Aerial photos from the disaster show the previously green landscape consumed by red sludge. With this disaster in mind, opponents of TMM fear that the mine’s waste will cause a similar waste explosion in the BWCA. 

The Twin Metals mining project is not only controversial because of its environmental and social justice issues, but it is also the center of a political conflict. Even though the project has been proposed since 2010, it was thought to have been squashed in 2016 when the Obama administration denied Twin Metals their two copper-nickel mineral leases [7]. However, less than two weeks after the Trump administration came into office, they renewed the mineral leases for TMM, claiming that the previous Interior Secretary did not have the discretion to deny the leases [7]. Additionally, in 2018, the Trump administration canceled the U.S. Forest Service environmental review that Obama had ordered that would have determined the wilderness impacts of keeping preserved lands from being converted to mining operations [13]. 

In reaction to this political quarrel, a coalition of environmental justice advocates, local businesses, and outdoor recreation groups filed a lawsuit against the U.S. Department of Interior and Twin Metals Minnesota in April 2019 [8]. In the lawsuit, the environmental groups are asking a federal judge to rule without a trial that the Trump administration wrongfully reinstated the two mineral leases, and the flip-flop of governmental policies is illegal. However, it is important to note that the judge for the lawsuit, Trevor McFadden, is a Trump appointee, pointing to an unsuccessful outcome. The plaintiffs view this lawsuit as the latest shot in the state’s prolonged battle over copper-nickel mining in Northeastern Minnesota. Essentially, it is the latest advancement in the decade-long chess game between Twin Metals Minnesota and its environmentalist opponents. 

The Twin Metals Minnesota mining project is currently ongoing. The company is still facing litigation from environmental groups, and there are many others that still actively oppose the development of the copper-nickel mine. TMM still faces a yearlong permitting and approval process under the National Environmental Policy Act and by the end of 2019, the company will be allowed to release its operating plan. In November 2019, the Minnesota Department of Natural Resources announced that they will conduct an independent environmental review of the mining and waste management plan of Twin Metals, as the state was disappointed by Trump’s cancellation of the review by the U.S. Forest Service. The DNR will be conducting an additional environmental review to ensure that the federal one is not tampered with. The state aims to conduct this review in an open, transparent, and public process [9]. 

Save the Boundary Waters is the primary nonprofit that led the successful campaign to temporarily halt mine exploration and initiate the ongoing federal environmental review of mining in the BWCA watershed. They are working alongside other environmental groups, such as Northeastern Minnesotans for Wilderness, Friends of the Boundary Waters and Voyageur Outward Bound School. Additionally, advocates from the Fond du Lac Band of Minnesota Chippewa are working in collaboration with the plaintiff organizations. Many opposing groups have organized protests against the construction of the mining facility. 

There are now a total of five lawsuits in the state and federal courts related to the protection of the Boundary Waters. According to Save the Boundary Waters, the five lawsuits can be described as follows [16]:

1.      Federal lawsuit #1: Reinstatement of Leases - This lawsuit is against the federal government for reinstating two expired federal mineral leases previously held by Twin Metals. These leases were lawfully extinguished in 2016, but brought back to life by the Trump administration. This suit was decided against us in the Washington, DC, District Court, but we appealed. The case is now under consideration in the DC Court of Appeals. We are represented by the national law firm of Morrison & Foerster.

2.      Federal lawsuit #2: Renewal of Leases- This lawsuit is also against the federal government. In it, we and the other plaintiffs claim that the federal government failed to follow rules under NEPA to adequately evaluate the renewal of the two resurrected Twin Metal mineral leases. This suit was filed in May 2020 in federal district court in Washington, DC. We are represented by the national law firm of Morrison & Foerster.

3.      State lawsuit: Minnesota Rules -  This lawsuit was filed against the State of Minnesota in June under the Minnesota Environmental Rights Act. In this suit, the Northeastern Minnesotans for Wilderness, the sole plaintiff, is represented by the law firm of CiresiConlin, LLC. We are challenging the Department of Natural Resources’s nonferrous regulations which we believe are insufficient to protect the Boundary Waters. If we are successful, the DNR will be compelled to rewrite the rules, and there will be an opportunity for consideration of current science. Specifically, we request that the rules be changed to prohibit sulfide-ore copper mining in the entire Rainy River Headwaters, which is the watershed of the Boundary Waters. Sulfide-ore copper mining is currently banned in the northern half of the Rainy River Headwaters (the Boundary Waters) but the southern half - which constitutes the headwaters of the watershed - is unprotected. Our contention is that the only way to ensure that the waters of the Boundary Waters remain clean and without degradation from mining is to ban sulfide-ore copper mining in the southern half. All waters in the southern half flow north into the northern half. Eighty percent of the Boundary Waters is in the northern half of the watershed and are at significant risk unless the DNR regulations are updated to reflect modern science and common sense.

4.      NEPA Lawsuit: Environmental Rollbacks - While Northeastern Minnesotans for Wilderness (lead organization of the Campaign to Save the Boundary Waters) is not a party in this lawsuit, our National Campaign Chair - Becky Rom - is cited as one of the affected persons. This lawsuit against the Trump administration challenges the recent evisceration of the National Environmental Policy Act (NEPA). Our partners in the fight to protect the Boundary Waters - EarthJustice and The Wilderness Society - are defending one of the nation’s most important environmental protection laws. Changes the Trump administration made will mean polluted water, degraded natural landscapes, and air that’s not fit to breathe and sharply limit public involvement in some of our nation’s most important natural resource decisions.

5.      Federal Lawsuit #3: Renewal of Prospecting Permits -  This lawsuit challenges the Trump administration over its decision to renew 13 prospecting permits that could allow Twin Metals to significantly expand its proposed sulfide-ore copper mine.

The Save the Boundary Waters is also asking people to sign a petition that will be used to show the public’s disapproval of the mine. If you are interested in signing it, you can find the petition via this link:

On September 30, 2020, President Trump signed an executive order that would fast-track mining permits in an effort to increase domestic mining, declaring a national emergency. According to the administration, this order will “cut down on unnecessary delays in permitting actions, providing Americans opportunities for jobs and improving economic and national security” [14]. However, with opposition from groups such as Save the Boundary Waters, this executive order does not necessarily mean that hope is lost for Minnesota’s Superior National Forest. Environmental review and permitting within the state is independent of federal authority, which includes the Minnesota Department of Natural Resource’s independent environmental review mentioned above [15]. Opposition to Twin Metals Mining must remain strong if this land is to be protected. 

The Boundary Waters are highly valued by Minnesotans and Canadians along the border. They must be protected from the threat of Twin Metals Minnesota causing environmental degradation and the loss of the livelihoods for the Native American Tribes and other inhabitants/visitors to the region. 

In short, the project’s progress is apparently going back and forth over the past three administrations. In 2016, former President Barack Obama’s administration refused to renew two leases that Twin Metals needs to operate the mine and also proposed a 20-year ban on other new mining projects in the watershed of the Boundary Waters.

However, those decisions were reversed by the Trump administration (2017-2021), and  Twin Metals again submitted the project plan to state and federal regulators, asking for a multi-year environmental review and permitting process [17]. 

Currently however, the Biden administration is in process to express its views on the project proposal and will either cancel the project or allow the project to progress [17]. 

Basic Data

Name of conflict:Twin Metals Minnesota Mining in Superior National Forest, USA
Country:United States of America
State or province:Minnesota
Location of conflict:Superior National Forest
Accuracy of locationMEDIUM (Regional level)

Source of Conflict

Type of conflict. 1st level:Mineral Ores and Building Materials Extraction
Type of conflict. 2nd level:Tailings from mines
Mineral processing
Specific commodities:Copper
Rare metals

Project Details and Actors

Project details

Since 2010, Twin Metals Minnesota (TMM) has invested $450 million in their proposed mining project in the Superior National Forest [9]. By the time of construction, TMM expects to invest a total of $1.7 billion. The project would involve about 5,000 acres of federal public land in the Superior National Forest. The hope of TMM is to create a mine that spans underground for 30,000 acres, which would be connected to a 100-acre mineral processing facility via 1 mile of pipeline. The project has been nicknamed the “underground city” and would involve miles of tunnels blasted below the surface with massive earth moving machines extracting the mineral material [3]. If permitted, Twin Metals Minnesota hopes to mine in the area for at least twenty-five years. The sheer size of the facility will allow the mine to process around 20,000 tons of mineralized ore per day using their underground operations system [1]. The company claims that it would bring economic prosperity to the area, hoping to create 700 full-time jobs as well as 1400 spin off jobs for the residents of the nearby towns. Their hope is that the promise of employment will resonate in Minnesota’s Iron Range, as the area has lost a quarter of its mining jobs since 2000 [10]. Additionally, the company advertises that they would generate significant tax and royalty revenue that would support nearly 900,000 K-12 students statewide [11]. Since the start of the Trump administration, Twin Metals has ramped up its lobbying in Washington, resulting in a total expenditure of $900,000 [10].

Although Twin Metals is enthusiastic about the project, its construction would most likely result in a plethora of environmental and environmental justice problems. Although the mining company claims that they have been conducting environmental studies concerning the operation for more than seven years, their actions do not show any regard for the pristine wilderness of the BWCA [1]. Mining in the area can cause up to 500 years of pollution in the nearby water bodies, contaminating the surface water, soil, and groundwater. This will severely impact the rural communities and indigenous populations, affecting their food sources and local environment. In 2018, two environmental groups created a commercial that highlighted the negative effects that mining would bring to the Boundary Waters [12]. The Boundary Waters Action Fund and The Friends of the Boundary Waters poured $20,000 into a commercial that undermined the political agenda of boasting the economic prosperity that the mine could bring to Ely and Babbitt, Minnesota. Even so, the environmental advocates are still battling the ongoing issue of the proposed construction of Twin Metals Minnesota.

Project area:12,140
Level of Investment for the conflictive project450,000,000.00
Type of populationSemi-urban
Affected Population:Population of Rainy River Watershed
Start of the conflict:01/01/2010
Company names or state enterprises:ANTOFAGASTA MINERALS (Grupo Luksic) (ANTO) from Chile
Twin Metals Minnesota (TMM) from United States of America
Relevant government actors:U.S. Department of Interior, U.S. Forest Service, Trump Administration, The State of Minnesota: Department of Natural Resources
Environmental justice organizations (and other supporters) and their websites, if available:Fond du Lac Band of Lake Superior Chippewa
The Minnesota Center for Environmental Advocacy
Save the Boundary Waters
Voyageur Outward Bound School
Friends of the Boundary Waters
River Point Resort
The Boundary Waters Action Fund
Sportsmen for the Boundary Waters
Northeastern Minnesotans for Wilderness
Center for Biological Diversity
The Wilderness Society

Conflict & Mobilization

IntensityMEDIUM (street protests, visible mobilization)
Reaction stagePREVENTIVE resistance (precautionary phase)
Groups mobilizing:Indigenous groups or traditional communities
Local ejos
Local businesses, Chippewa (also known as the Ojibwe) peoples
Fisher people
Forms of mobilization:Lawsuits, court cases, judicial activism
Media based activism/alternative media
Public campaigns
Street protest/marches


Environmental ImpactsPotential: Air pollution, Food insecurity (crop damage), Loss of landscape/aesthetic degradation, Soil contamination, Surface water pollution / Decreasing water (physico-chemical, biological) quality, Groundwater pollution or depletion, Mine tailing spills
Other Environmental impactsRunoff and/or toxic waste pollution from the mine will cause surface water, soil, and groundwater contamination. The nearby water bodies are likely to be severely contaminated.
Health ImpactsPotential: Occupational disease and accidents, Other environmental related diseases
Other Health impactsIf the soil and water is contaminated by the mine, then methylmercury will accumulate in the aquatic systems as well as in food grown in the soil. Methylmercury is toxic for human consumption, and will therefore cause negative health impacts. Specifically, the Fond du Lac Band of the Minnesota Chippewa are at risk of consuming toxins, as they cultivate large amounts of wild rice on the land nearby.
Socio-economical ImpactsPotential: Loss of livelihood, Loss of traditional knowledge/practices/cultures, Loss of landscape/sense of place
Other socio-economic impactsThe Fond du Lac Band of the Minnesota Chippewa are guaranteed by treaty the right to cultivate wild rice on the land of the Boundary Waters. Pollution and contamination of this land will disrupt their foodway and their harvesting traditions.


Project StatusProposed (exploration phase)
Conflict outcome / response:Court decision (undecided)
Under negotiation
Project temporarily suspended
Proposal and development of alternatives:Environmental groups are fighting for the complete outlaw of the development of a copper-nickel mine in the Boundary Waters watershed. Due to this, Twin Metals Minnesota should not be allowed to continue operations in their proposed location. An alternative location could be considered, yet it would be unlikely that Twin Metals would desire a location further from the Maturi deposit. Frankly, the Boundary Waters Watershed is not the right spot for this mine, and any alternative routes of development should involve a different location.
Do you consider this an environmental justice success? Was environmental justice served?:Not Sure
Briefly explain:The Twin Metals Minnesota mining proposal has not yet been approved and justice will depend upon a full environmental impact assessment and the outcome of the ongoing litigation and the current Biden Administration. This issue could have been an environmental justice success when the Obama administration withheld the mineral leases from TMM; however, since the Trump administration has reinstated the mineral leases, it is obvious that the federal agenda is to strengthen the mining industry, no matter the consequences. Justice should be served to the indigenous and rural populations of the Boundary Waters watershed, yet only time will tell if this will happen. With the Trump Administration's recent executive order to fast track domestic mining, the threat against the Superior National Forest continues and the conflict remains ongoing. Now, the Biden Administration is examining the project proposal and will either refuse the project as claimed by activist and EJOs, or will allow the project.

Sources & Materials

[1] Twin Metals Minnesota. (2019, December). About The Project. Retrieved December 9, 2019.

[2] Tabuchi, H., & Eder, S. (2019, June 25). A Plan to Mine the Minnesota Wilderness Hit a Dead End. Then Trump Became President. Retrieved December 10, 2019.

[3] The Sierra Club. (2018, May 26). Twin Metals. Retrieved December 10, 2019.

[4] Minnesota Chippewa. (2019, December). Fond du Lac Band of Lake Superior Chippewa. Retrieved December 10, 2019.

[5] Timmer, S., Snyder, E., Timmer, S., Berkelman, T., Flanagan, Musich, J., … Tribal Cooperating Agencies. (2019, September 12). At issue in Minnesota's sulfide mining debate: environmental justice. Retrieved December 10, 2019.

[6] MPR News. (2019, July 18). Twin Metals pitches new method of storing waste at proposed mine near BWCA. Retrieved December 10, 2019.

[7] Marcotty, J. (2017, December 23). Feds reject Obama-era ruling that blocked mining on edge of BWCA. Retrieved December 10, 2019.

[8] Bjorhus, J. (2019, April 18). Minnesota group ramps up court challenge to Trump rulings on Twin Metals mining leases. Retrieved December 10, 2019.

[9] Olsen, T. (2019, November 22). DNR to complete independent review of Twin Metals. Retrieved December 10, 2019.

[10] Tabuchi, H., & Eder, S. (2019, June 25). A Plan to Mine the Minnesota Wilderness Hit a Dead End. Then Trump Became President. Retrieved December 10, 2019.

[11] Twin Metals Minnesota. (2019, April). Fact Sheet: Twin Metals Federal Lawsuit to Protect Mineral...Retrieved December 10, 2019.

[13] Grandoni, D., and Eilperin, J. (2018, January 26). Trump administration cancels detailed review of Obama-era mining ban near Minnesota wilderness. Retrieved October 12, 2020.

[14] The White House. (2020, 30 September). President Donald J. Trump Is Protecting Our Domestic Mining Industry and Critical Minerals Supply Chains. Retrieved October 26, 2020.

[15] Schneider, G. (2020, 2 October). What Trump’s new executive order actually means for mining in Minnesota, Retrieved October 26, 2020.

[16] Campaign to Save the Boundary Waters. (2020, August 5). Update: 5 Lawsuits to Protect the BWCA. Retrieved October 31, 2020.

[17] MPR News 2021: The Biden administration is poised to weigh in on Twin Metals mine: Here are the options

Meta information

Contributor:Emily Chase, Skidmore College, [email protected]; Siddharth Nizamuddin, Skidmore College; Amity Wilson, Skidmore College; A.J. Schneller, Skidmore College
Last update18/10/2021
Conflict ID:4933



Workers at Twin Metals

Possible Mine Destruction

TMM Operational Facility Amidst Wilderness

Land threatened by Twin Metals proposal

Citizens protesting TMM

Mine Site and Path of Pollution Map

Twin Metals Operational Facility in Ely, MN