/ Project Overview

Project Overview

The Resolution Copper project is a proposed underground copper mine 60 miles east of Phoenix, Arizona, near the town of Superior. The Arizona project is a joint venture between two global mining companies, Rio Tinto (55%) and BHP (45%).

The project has the potential to become one of the largest copper mines in United States.

The copper deposit lies deep underground, between 5,000 and 7,000 feet below the surface. It is considered one of the largest undeveloped copper resources in the world, with studies estimating an average copper grade of about 1.5 percent1. Over an expected operating life of up to 40 years, the mine could produce as much as 40 billion pounds of copper and supply up to 25 percent of U.S. copper demand.

We have strong community and regional support for the project, which has the potential to become one of the largest copper mines in America, add $1 billion a year to Arizona’s economy, and create thousands of local jobs in a region where mining has played an important role for more than a century.

Resolution Copper continues to work with local communities, Tribal Nations, and regional partners to advance the project responsibly.

You can find updates on where the project stands and what comes next on our current status page.

To learn how the mine would operate, read more about the planned mining method and how copper would be safely recovered deep underground using a well‑established approach called caving.

1 This copper grade for the Resolution Mineral Resource was reported in accordance with the JORC Code and the ASX Listing Rules in Rio Tinto’s 2024 Annual Report released to the ASX on 20 February 2025. Rio Tinto confirms that it is not aware of any new information or data that materially affects the information included in the 2024 Annual Report, that all material assumptions and technical parameters underpinning the estimates in the 2024 Annual Report continue to apply and have not materially changed, and that the form and context in which the Competent Persons’ findings are presented have not been materially modified.

Resources

Our Work

The Descent: What It’s Like Traveling Nearly 7,000 Ft. Underground

From the surface, 7,000 ft. is hard to picture. It is just a number until you walk toward the shaft, pass beneath the headframe and reach the collar, where the scale starts to come into focus. The opening drops below, surrounded by steel, hoisting equipment and the systems that move people safely between the surface and the underground workings.

Testing What Matters Most: How One Team Helped Make Underground Refuge Chambers Even Safer

When people think about mine safety, they often picture hard hats, reflective clothing and safety inspections. Those are all important, but some of the most important safety work happens long before an emergency occurs, through planning, testing and preparation.

8 Billion Gallons Recycled: Our Commitment to Responsible Water Management

Since 2009, Resolution Copper has treated and provided more than 8 billion gallons of water for agricultural use in Arizona. It is a major milestone for a program that starts nearly 7,000 feet underground and ends in local farm fields.

Resolution Copper awards $110 million in US contracts to advance underground mine

Resolution Copper has awarded approximately $110 million in contracts to Major Drilling America Inc. and Redpath USA Corporation to advance exploration and underground development at the proposed Resolution Copper mine in Arizona.

Every gallon has a job: David’s work in water services

Before anyone can mine copper nearly 7,000 feet underground, someone must move the water. That’s where David comes in. As Water Services Supervisor at Resolution Copper, David helps oversee the systems that treat water pumped from the mine workings while also supporting the site’s potable water system. It’s work that blends science, troubleshooting and teamwork, all with one goal: keeping water moving safely and putting it to good use.

Resolution Copper Establishes $54 Million Tribal Trust

Resolution Copper has provided $54 million to establish the Resolution Copper Tribal Trust, a perpetual endowment that will deliver annual funding to eleven Tribal Nations located in Arizona and New Mexico for cultural preservation, education, youth development, workforce opportunities, language revitalization and other priorities they determine.

Q2 2026 Scorecard: Looking at the Numbers Behind Our Work

Every few months, we publish a scorecard to share where the project stands and what we've been working on. Numbers never tell the whole story, but they help show where we're making progress, where we're investing, and where our attention remains focused. 

Stewardship You Can See at Oak Flat Campground

If you're planning a visit to Oak Flat, here's the most important thing to know: Oak Flat Campground remains open.

Resolution Copper Awards $51,000 in Scholarships to 20 Local Students

Resolution Copper is proud to announce the recipients of its 2026 Scholarship Program, awarding 20 scholarships totaling $51,000 to outstanding students from communities across the Copper Triangle.