Rio Tinto Adds $144 Million to Arizona Copper Project

Rio Tinto approved a $144 million investment in the Resolution Copper project near Superior, Arizona, according to the company. Rio Tinto will provide $79 million of the total. The operating joint venture is 55%-owned by Rio Tinto and 45%-owned by BHP.

Rio Tinto said the commitment supports the next development phase at what it calls one of the world’s largest undeveloped copper deposits. The company linked that step to a land exchange completed in March 2026, which enabled Resolution Copper to enter the next phase.

The $144 million is separate from approximately $500 million in preliminary spending that Rio Tinto announced earlier in the year. The company said the new commitment advances underground engineering and prepares technical inputs for a future investment decision.

What can Resolution Copper deliver?

Rio Tinto estimates that Resolution Copper could eventually supply up to 25% of U.S. copper demand for several decades. The company tied that estimate to successful development and production, neither of which the current commitment guarantees.

Katie Jackson, chief executive of Rio Tinto Copper, said:

“Resolution Copper has the potential to supply up to 25% of America’s copper demand for decades, strengthen domestic supply chains and deliver significant economic benefits for Arizona.”

Rio Tinto links the project’s strategic value to increasing copper consumption across electricity infrastructure, transportation, industrial equipment and other applications. The company also identifies electrical wiring, power transmission systems, renewable energy technologies and electric vehicles as important copper users.

Rio Tinto argues that a major new domestic source could strengthen U.S. supply chains and reduce reliance on imported materials. The company estimates a completed Resolution Copper project could create thousands of direct and indirect jobs and contribute approximately $1 billion annually to Arizona’s economy.

What does the $144 million fund?

The funding will pay for feasibility studies and final engineering designs for material-handling systems serving the project’s development and production shafts. Rio Tinto will also finance engineering for new water-treatment facilities, continued exploration drilling and the acquisition of underground mining equipment.

Rio Tinto will also buy long-lead electrical equipment and other required infrastructure. Those purchases will prepare Resolution Copper for future development decisions. The money advances engineering, equipment procurement and construction readiness without authorizing full-scale mine construction.

Approximately 50 additional positions are expected across mining, geological, geotechnical, engineering and project services disciplines. The hiring plan brings specialized staff into the project as Rio Tinto works through underground design and technical studies.

How deep is the copper deposit?

Rio Tinto places the Resolution Copper deposit approximately 5,000 to 7,000 feet underground. At that depth, the project faces substantial engineering and infrastructure requirements, and the company expects to use underground mining technologies to reach the copper resource.

What remains undecided?

Katie Jackson said:

“Following completion of the historic land exchange in March, this investment is another important step in advancing the project. These funds will accelerate underground development, create additional skilled roles and ensure Resolution Copper is well positioned for its next investment decision, while maintaining safe underground operations and construction.”

The $144 million approval remains a development-stage commitment, not a final commercial decision. Rio Tinto said the project still requires engineering, equipment procurement and technical work before the next investment decision. The funding also maintains the company’s focus on underground safety and construction readiness.

The next test is whether that work converts into a full-scale construction decision. Until Rio Tinto takes that step, the projected 25% share of U.S. copper demand and $1 billion annual Arizona contribution remain long-term estimates tied to successful development and production.