KEY POINTS
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Rio Tinto and BHP approve an additional $144m for the Arizona copper project.
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The investment will fund engineering, underground development and exploration work, creating 50 jobs.
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Resolution Copper could supply up to 25% of US copper demand and contribute $1bn annually to Arizona’s economy.
Resolution Copper Mining, a joint venture between Australian mining giants Rio Tinto and BHP, has approved a further $144 million investment to advance development of its large-scale copper project in Arizona, United States.
The investment will support the next phase of work at the Resolution Copper project, regarded as one of the world’s largest undeveloped copper deposits and a potential major source of domestically produced copper for the US.
The latest funding follows the completion of a historic land exchange in March 2026, which cleared the way for further development. It is additional to approximately $500 million in preliminary spending announced at the time.
The new investment is expected to accelerate underground development, support engineering and feasibility work, and prepare the project for its next major investment decision.
Funding to Support Engineering and Underground Development
According to Rio Tinto, the $144 million programme will finance feasibility studies and final design engineering for materials handling equipment at the mine’s two shafts.
It will also support the installation of new water treatment facilities, further exploration drilling and the purchase of underground development and production equipment.
Part of the funding will go towards acquiring long-lead electrical equipment needed for the project’s continued development.
The programme is intended to advance critical infrastructure and technical preparations required before the mine can move towards full-scale production.
Project to Create 50 Additional Jobs
Rio Tinto said the latest investment would create approximately 50 additional positions across several technical and professional fields.
The new roles will cover mining, geotechnical and geological disciplines, engineering and project services.
Rio Tinto Copper Chief Executive Katie Jackson said the project could eventually supply up to 25% of US copper demand for decades, strengthening domestic supply chains while generating significant economic benefits for Arizona.
She described the latest funding as an important step following the completion of the land exchange, adding that it would accelerate underground development and position the project for its next investment decision.
Jackson also stressed the importance of maintaining safe underground operations and construction activities as development progresses.
Resolution Copper Could Contribute $1bn Annually to Arizona
Rio Tinto estimates that Resolution Copper could become one of the largest copper mines in the United States, generating thousands of direct and indirect jobs and contributing approximately $1 billion annually to Arizona’s economy.
Resolution Copper Mining President Vicky Peacey said the investment would build on the momentum created by the land exchange and accelerate progress towards the project’s first copper production.
She said the company intended to advance development with urgency while maintaining discipline and safety standards.
The project is expected to play a significant role in expanding US copper production at a time when demand for the metal remains important to infrastructure, electrification and industrial development.
Rio Tinto to Provide Majority of New Investment
Rio Tinto, which owns a 55% stake in Resolution Copper Mining, will contribute approximately $79 million of the latest $144 million investment.
The remaining funding will come from its joint venture partner, BHP, which holds the other 45% interest.
The investment represents another development milestone for the project, although further studies, engineering work and investment decisions will be required before production can begin.
