Resolution Copper Completes Historic Land Exchange, Unlocking Major Arizona Copper Deposit

The Land Exchange

Resolution Copper, the joint venture 55% owned by Rio Tinto and 45% owned by BHP, has completed a landmark land exchange with the United States Forest Service (USFS) that clears the way for development of one of the world’s largest and deepest untapped copper deposits in Superior, Arizona.

Under the terms of the exchange, Resolution Copper transferred more than 5,400 acres of land containing special status species habitats, riparian areas, and Native American cultural sites. These parcels have been incorporated into National Forests and National Conservation Areas, providing long-term environmental and cultural protections.

In return, Resolution Copper received over 2,400 acres adjacent to the historic Magma copper mine — the site where underground development activity is planned. The deposit beneath it is believed to be one of the largest untapped copper deposits/resources in the world. The exchange was enabled by legislation attached as a rider to the National Defense Authorization Act for Fiscal Year 2015, which passed with bipartisan support in 2014. The process has since involved more than a decade of consultation and coordination with civil society organisations, the Town of Superior, and Native American Tribes.

Legal and Regulatory Path

The land parcel received by Resolution Copper — known as Oak Flat, or Chí’chil Biłdagoteel in the Apache language — is the central point of a years-long legal and cultural dispute. The San Carlos Apache Tribe and the coalition Apache Stronghold have argued that the site is a sacred place of prayer and ceremony that has been used by Western Apache peoples since time immemorial, and that mining it would create a crater estimated to be two miles wide and more than 1,000 feet deep, permanently destroying the site.

The legal battle has progressed through multiple courts. In March 2024, the Ninth Circuit Court of Appeals ruled en banc — with six judges in favour and five dissenting — that the land transfer did not constitute a substantial burden on religious freedom under the Religious Freedom Restoration Act. Apache Stronghold appealed to the US Supreme Court. On 27 May 2025, the Supreme Court declined to hear the case; Justices Gorsuch and Thomas dissented, calling the refusal a “grave mistake”. The Supreme Court again declined to rehear the case in October 2025.

The most recent ruling came on 13 March 2026, when the Ninth Circuit denied requests for preliminary injunctive relief to stop the exchange — clearing the way for the land transfer to be completed on 16 March. Litigation in lower courts on separate related claims is still ongoing, and the exchange remains contested by opponents.

“Completing the land exchange is a significant milestone and another positive step forward for the Resolution Copper project, which has the potential to satisfy up to 25% of America’s copper demand for decades to come.”

— Katie Jackson, Chief Executive, Rio Tinto Copper

Project Scope and Investment

Resolution Copper has announced approximately $500 million in preliminary spending spread over the next two years. The funding will support a range of enabling activities including surface drilling to gather additional resource information, infrastructure upgrades to existing project facilities, initial underground development, and funding to support Native American Tribes and local communities.

The expenditure is also expected to generate around 100 new jobs in the near term, with the full project anticipated to create thousands of local positions during construction and operations. The mine is projected to add $1 billion per year to Arizona’s economy, a region where copper and mineral extraction have been central to economic life for more than a century.

Full mine development remains subject to state-level permitting, additional studies, enabling work, and continued community and tribal engagement.

Copper Market Context

The Resolution Copper project comes at a time of growing strategic interest in domestic copper supply in the United States. Copper is a critical material for electrification, clean energy infrastructure, and advanced manufacturing, with demand expected to grow substantially over the coming decades.

Rio Tinto has been actively expanding its copper portfolio, characterizing the metal as central to its long-term growth strategy. The company’s copper business spans major operations including Kennecott in Utah, a 30% stake in Escondida in Chile (the world’s largest copper mine), the Oyu Tolgoi mine in Mongolia, and the Resolution project.

Rio Tinto Copper Chief Executive Katie Jackson noted that demand for copper continues to grow and that projects like Resolution can play an important role in strengthening domestic US supply chains. The company also highlighted the US Government’s growing recognition of the need for domestically sourced critical materials.

BHP, which holds the remaining 45% stake in the Resolution joint venture, has similarly positioned copper as a core growth commodity in its long-term portfolio strategy. Bringing the Resolution deposit into production would represent a major addition to North American copper supply for both companies.