Resolution Copper

Resolution Copper is a joint venture formed by Rio Tinto and BHP to develop a proposed underground copper mine near Superior in central Arizona. The project targets a large, deep-seated porphyry copper deposit beneath Oak Flat and the former Magma Mine area. It is intended to become one of the largest potential copper mines in North America and is frequently discussed in the context of United States copper supply, critical-mineral policy, Indigenous religious rights, federal land management, and environmental protection. The proposed operation would use underground mining rather than an open pit. Rio Tinto has reported an inferred resource of approximately 1.624 billion tonnes containing about 1.47 percent copper and 0.037 percent molybdenum, at depths greater than 1,300 metres. Resolution Copper has also acquired mineral rights associated with the Superior East deposit, another deep porphyry copper occurrence located roughly a mile east of the main resource. The company has described the proposed mine as a multidecade operation, estimating a life of more than 60 years and production equivalent to around one-quarter of projected future United States copper demand for several decades. Development has depended heavily on a federal land exchange. Resolution Copper proposed transferring thousands of acres of private and environmentally sensitive land to the federal government in exchange for the 2,422-acre Oak Flat federal parcel. Oak Flat, also known as Chi’chil Bildagoteel, is a protected recreational area containing archaeological and cultural resources, including petroglyphs and historic and prehistoric sites. It is sacred to the San Carlos Apache Tribe and important to other Apache people. The proposed transfer and mine have therefore generated sustained opposition from Indigenous organizations, conservation groups, and other public-interest advocates. The land exchange was incorporated into Section 3003 of the 2015 National Defense Authorization Act after earlier standalone legislation had stalled. The federal government subsequently prepared an environmental review and land-transfer process. The Biden administration withdrew the final environmental impact statement in March 2021 to allow additional public and tribal input. Litigation followed, including challenges based on the Religious Freedom Restoration Act and related constitutional and federal-law claims. Federal courts ultimately upheld the government's authority to transfer the land, while continuing legal and political disputes reflected the conflict between mineral development and protection of sacred places. In May 2025, the United States Supreme Court declined to disturb a lower-court decision allowing the transfer, although other proceedings and implementation questions remained part of the project's public controversy. Resolution Copper has invested in exploration, engineering, preparation, community programs, and local infrastructure. Reference material states that cumulative spending exceeded $2 billion by early 2023, while earlier estimates described nearly $1 billion spent through 2012 and a possible development investment of roughly $6 billion if the land exchange were approved. These figures are project estimates rather than operating revenue or public-company financial results. The project has not been described as an operating mine in the supplied reference material; its identity remains that of a proposed copper-development venture. Its public positioning combines domestic copper production, long-term resource development, employment, and community investment with commitments to environmental management and engagement with affected tribes. Critics continue to argue that the mine would irreversibly damage Oak Flat and undermine Indigenous cultural and religious rights.

Resolution Copper is a joint venture between Rio Tinto and BHP established to develop a large underground copper deposit near Superior, Arizona. The deposit lies beneath Oak Flat and the area of the inactive Magma Mine, in the Superior mining district. The project is based on a deep porphyry system and has been described as one of the largest undeveloped copper resources in North America. Rio Tinto has reported an inferred resource of approximately 1.624 billion tonnes grading 1.47 percent copper and 0.037 percent molybdenum. The mineralization lies more than 1,300 metres below the surface, making the project technically complex and requiring extensive underground infrastructure. The project also controls mineral rights associated with the Superior East deposit, another deep porphyry copper occurrence approximately one mile east of the principal Resolution resource. Resolution Copper's development plans have contemplated a mine operating for more than six decades. The company has estimated that the project could eventually supply approximately 25 percent of projected future United States copper demand for several decades. Copper's use in electrical infrastructure, construction, transportation, and energy systems has made the project relevant to debates about domestic supply and mineral security. A central issue has been ownership and access to Oak Flat. The federal government protected the Oak Flat Campground in 1955. The site contains archaeological resources, petroglyphs, climbing areas, and places regarded as sacred by the San Carlos Apache Tribe and other Apache people. Resolution Copper proposed an exchange under which it would receive approximately 2,422 acres of federal National Forest land at Oak Flat and convey more than 5,000 acres of private or environmentally sensitive land to the federal government. Earlier legislative efforts to authorize the exchange stalled. In 2009, Representative Ann Kirkpatrick introduced legislation to advance it, and in 2013 Representative Paul Gosar introduced the Southeast Arizona Land Exchange and Conservation Act. The exchange was ultimately incorporated into Section 3003 of the 2015 National Defense Authorization Act, following sponsorship by Senators John McCain and Jeff Flake. The legislation moved the project into a federal environmental review and land-transfer process. The initial environmental report was issued during the Trump administration, with the transfer scheduled for March 2021. The Biden administration withdrew the report on March 2, 2021, citing the need for additional public and tribal input. Resolution Copper and its parent companies faced opposition from the San Carlos Apache Tribe, the National Congress of American Indians, the National Audubon Society in Tucson, the Sierra Club's Grand Canyon Chapter, and other conservation and Indigenous-rights groups. Opponents argued that the transfer would destroy or severely damage a sacred site and that the legal mechanism did not provide adequate consent or protection. Litigation became a defining part of the project's history. In 2021, the San Carlos Apache Tribe challenged the land exchange, arguing that it violated constitutional and religious-freedom protections. A Ninth Circuit panel upheld the government's authority to make the transfer in 2022, and the court later agreed to rehear the case en banc. During a 2023 hearing, Forest Service representatives disputed the proposition that an 1852 treaty created an Apache right to the land containing the copper deposit. On March 1, 2024, the en banc Ninth Circuit ruled 6–5 that the transfer did not constitute a substantial burden on the tribe's religious exercise because the government was not directly prohibiting worship or requiring tribal members to abandon their deities. Apache Stronghold sought Supreme Court review. In May 2025, a federal district judge temporarily blocked efforts by the administration to transfer the land, finding that the Apache plaintiffs were likely to prevail in their appeal and that the transfer should be paused pending Supreme Court action. On May 27, 2025, the Supreme Court declined to hear Apache Stronghold's appeal, leaving the lower-court decision permitting the transfer in effect. The ruling did not eliminate the broader political, cultural, environmental, and implementation disputes surrounding the project. Resolution Copper has reported extensive spending on exploration and project preparation. Reference material states that almost $1 billion had been invested by 2012, that the development plan contemplated approximately $6 billion in further investment if the exchange were approved, and that more than $2 billion had been spent on exploratory work and preparation by early 2023. The company has also described local investments in Superior facilities, employment opportunities, tribal-benefit initiatives, and a grove-preservation program conducted with the United States Forest Service and Northern Arizona University. The supplied sources do not establish a commercial production date, and the project remains characterized as a proposed mine rather than an operating copper producer.

• 2025

  Supreme Court leaves transfer ruling in place

  [1]Resolution Copperen.wikipedia.org

  The Supreme Court declined Apache Stronghold's appeal, leaving the lower-court decision authorizing the transfer in effect.

• 2024

  En banc Ninth Circuit rejects religious-rights challenge

  [1]Resolution Copperen.wikipedia.org

  The full Ninth Circuit ruled that the land transfer did not impose a substantial burden on the San Carlos Apache Tribe's religious exercise under the applicable legal test.

• 2022

  Ninth Circuit initially upholds transfer authority

  [1]Resolution Copperen.wikipedia.org

  A divided Ninth Circuit panel upheld a lower-court conclusion that the federal government could carry out the land exchange.

• 2021

  Environmental review is withdrawn for further consultation

  [1]Resolution Copperen.wikipedia.org

  The Biden administration withdrew the previously issued environmental report and sought additional input from the public and Indigenous nations.

• 2015

  Section 3003 authorizes the land exchange

  [1]Resolution Copperen.wikipedia.org

  The National Defense Authorization Act included provisions clearing a path for Resolution Copper to receive the Oak Flat federal parcel in exchange for thousands of acres of private land.

• 2013

  Southeast Arizona land-exchange bill is introduced

  [1]Resolution Copperen.wikipedia.org

  Representative Paul Gosar introduced H.R. 687, which included provisions protecting the natural character of Apache Leap and addressing related mining rights.

• 2009

  Congressional legislation seeks to complete exchange

  [1]Resolution Copperen.wikipedia.org

  Representative Ann Kirkpatrick introduced legislation intended to advance the Southeast Arizona land exchange.

• 2008

  Project stalls over proposed land exchange

  [1]Resolution Copperen.wikipedia.org

  Development remained stalled while Resolution Copper and the federal government pursued authorization for an exchange involving Oak Flat.

• 1955

  Oak Flat receives federal protection

  [1]Resolution Copperen.wikipedia.org

  President Dwight D. Eisenhower set aside Oak Flat as a protected federal recreational area, later making the site a central issue in the Resolution Copper land exchange.

A major proposed United States copper-mining project emphasizing long-term domestic supply, underground resource development, local economic benefits, and environmental management, while facing significant Indigenous-rights and conservation opposition.

• Copper mining project

  Resolution Copper underground mine

  The proposed flagship operation is a deep underground mine near Superior, Arizona. It is designed to access a porphyry copper deposit beneath Oak Flat and the former Magma Mine area. The project is expected to require extensive shafts, underground workings, processing facilities, and supporting infrastructure. Reference material describes a potential operating life exceeding 60 years and production capable of supplying a substantial share of projected United States copper demand, but does not establish a commercial production date.

• Copper mineral resource

  Superior East deposit

  Resolution Copper holds mineral rights acquired from ASARCO for the Superior East deposit, a deep-seated porphyry copper occurrence located approximately one mile east of the principal Resolution deposit. The supplied reference material identifies it as an additional resource associated with the broader Superior mining district, but does not provide a separately confirmed development schedule or production plan.

• Community investment and employment initiatives

  Superior, Arizona

  Resolution Copper has promoted investments in Superior town facilities and employment opportunities as part of its effort to demonstrate local economic benefits from the proposed mine.

  Outcome. The initiatives are cited as community-benefit measures, while opposition to the project remains active.

  Source
• Grove preservation program

  Arizona

  The company has participated in a grove-preservation program with the United States Forest Service and Northern Arizona University as part of its environmental commitments.

  Outcome. The program is presented as a mitigation and conservation measure, although it has not resolved the central dispute over Oak Flat.

  Source

• 2021

  Continue development while federal review is revisitedStrategy

  Background

  The Biden administration withdrew the environmental report shortly before the scheduled transfer to seek additional public and tribal input.

  Action taken

  Resolution Copper and its owners continued pursuing the project and engagement while the federal review and land-transfer process were reconsidered.

  Aftermath

  The project remained in development and litigation rather than moving directly into construction.

  Source

• 2015

  Proceed under Section 3003 of the National Defense Authorization ActOther

  Background

  Standalone land-exchange legislation had not completed the federal legislative process.

  Action taken

  The project proceeded under the land-exchange provisions included in the National Defense Authorization Act.

  Aftermath

  The act created a federal pathway for the exchange, but litigation and public controversy continued.

  Source

• 2008

  Pursue federal land exchange as the project pathwayStrategy

  Background

  The proposed mine required access to federally controlled land at Oak Flat, while earlier development efforts were stalled.

  Action taken

  Resolution Copper pursued an exchange involving approximately 2,422 acres of federal land and more than 5,000 acres offered to the federal government.

  Aftermath

  The strategy led to congressional authorization but also became the basis of sustained Indigenous-rights, environmental, and legal opposition.

  Source

1. 1Resolution Copperen.wikipedia.org
2. 2Resolution Copper official websiteresolutioncopper.com