Rio Tinto approved a $144 million development program for Resolution Copper’s Arizona mine project, funding work that advances the site toward a later investment decision without setting a production timetable.
Resolution Copper announced the plan on Nov. 5. Rio Tinto said it would contribute $79 million. The program adds to about $500 million in preliminary spending announced in March 2026, which Rio Tinto said would be spread over two years.
The new funding covers feasibility studies and final design engineering for material-handling equipment in both mine shafts, as well as new water-treatment facilities. It also includes exploration drilling, underground development and production equipment, and long-lead electrical equipment. Resolution Copper plans to add about 50 roles across mining, geotechnical and geology work, engineering and project services; the announcements gave no hiring schedule.
Rio Tinto owns 55% of the Resolution Copper joint venture, and BHP owns 45%. The companies provided no date for the next investment decision or target year for first copper production.
The project’s development follows a land exchange completed in March. Rio Tinto said the deal gave Resolution Copper a parcel of more than 2,400 acres near Superior, while allocating more than 5,400 acres to national forests and conservation areas. The Ninth Circuit described Oak Flat, which was part of the exchange, as an Apache ceremonial religious ground. The San Carlos Apache Tribe and other groups challenged the exchange. The court upheld the denial of a preliminary injunction on March 13 and denied rehearing petitions on Sept. 29.
Resolution Copper says its deposit lies 5,000 to 7,000 feet underground. The company projects the project could support thousands of direct and indirect jobs and contribute about $1 billion a year to Arizona’s economy. Rio Tinto Copper Chief Executive Katie Jackson said the mine could account for as much as 25% of U.S. copper consumption over the coming decades.
