PROTECTING AND CONSERVING WATER

Resolution Copper is permitting one of the world’s largest untapped copper deposits in Arizona’s Copper Triangle. Once in operation, the mine will be one of the largest in the United States. We take water conservation very seriously. We’re committed to transparency and constant improvement when it comes to water use, seeking ways to implement state-of-the-art technology to help further minimize our water needs in the long term.

One of the Most Water-Efficient Copper Mines in the U.S.

Resolution Copper will be the most water-efficient mine in Arizona – using fewer gallons of water per pound of copper produced than any other mine operating in Arizona. That means every drop of water used at Resolution Copper goes further than water used in other copper mines and brings more benefits to the region.

At maximum operations, Resolution Copper will use less than 5 gallons of water per pound of copper, compared to the approximately 10-50 gallons of water per pound of copper produced in other copper mines.

At Resolution Copper, we focus on reducing water usage across our operations, minimizing evaporation, and reusing and recycling water whenever possible. We have already stored enough water to sustain our operations, assuming maximum production for more than half the mine’s operating life. And the Environmental Impact Statement (EIS), currently undergoing republication by the US Forest Service as of April 2025, demonstrates an adequate water supply for all cumulative uses for the next 100 years.

Focus on Transparency and Investing in Technology

From the beginning, we have welcomed input from experts and local communities. We have worked hard to address any concerns about water use in ongoing consultation with community groups and Native American Tribes. Resolution Copper has committed to using the latest technology proven at our scale to increase recycling and reduce water use, but we think we can do better. It will be at least a decade until Resolution Copper begins formally operating, and we are actively exploring ways to further reduce our water use and needs over time. Our key water reduction methods include:

• Operating as an underground mine, which requires less water for dust
  control as compared to open-pit mines.
• Lining a portion of the tailings facility, reducing water loss.
• Thickening tailings to higher solids concentrations (60%) resulting in 43%
  of water being recovered for recycling and reuse, in comparison
  to typical tailings facilities in Arizona with 50% solids concentration,
  resulting in 29% of water being recovered.

Providing Water to Local Farmers

As we dig, the water we remove from 7000 feet below the ground in bedrock goes through an on-site treatment process and is then sent to an irrigation district where farmers use it to grow crops. By beneficially using our treated water, farmers pump less, leaving more water in the ground. Continuous monitoring ensures the water meets regulatory standards. Since 2009, Resolution Copper has provided approximately 7 billion gallons of water to local farmers.

Adhering to Water Regulations

Resolution Copper complies with all federal, state, and local laws for water quality and water use, including the National Environmental Policy Act (NEPA) and the Clean Water Act. We have invested in an extensive surface and groundwater monitoring network and multiple federal, state, and local regulators oversee our work. We have also partnered with the Town of Superior to collaborate on water studies, monitoring, and restoration efforts.

Protecting Aquatic Habitats

Resolution Copper’s land exchange with the federal government will transfer more than 5,400 acres of land into public hands, protecting the habitats of threatened and endangered aquatic creatures, while preserving miles of creeks and rivers in their entirety.

The Lower San Pedro River parcel, the largest of all the land parcels in the exchange, has an ecosystem noted by the Nature Conservancy as one of the “Last Greatest Places on Earth” and has earned the distinction of “Important Bird Area” from prominent bird groups. Transferring these lands into public hands will enable the government to prioritize conservation efforts and protect vulnerable habitats of threatened and endangered aquatic creatures while preserving miles of creeks and rivers in their entirety.

Water Use and Monitoring

In 2017, Resolution Copper partnered with the local Community Working Group (CWG) to form a community monitoring program. The CWG hired a consultant to take quarterly groundwater samples from locations surrounding the project area to establish baseline conditions and monitor current activities. Samples are sent to an independent testing laboratory and the results are compared against compliance requirements and shared with the CWG and Resolution Copper for discussion. The sampling fosters transparency, information sharing, two-way dialogue, and trust.

We have already stored enough water to sustain our operations for more than half the mine’s operating life. The Environmental Impact Statement (EID) previously published by the US Forest Service demonstrates there is adequate water supply for all cumulative uses in full compliance with the law for the next 100 years.

Resolution Copper does not and will not withdraw water from the San Carlos Apache Tribe or the Cutter Basin.

Resolution Copper does not have the physical infrastructure or legal authority to withdraw water from the boundaries of the San Carlos Apache Indian Tribe or the Cutter Basin. The Project’s future water supply is from groundwater collected at 7,000 feet deep in the mine and an area located 50 miles away from the San Carlos community.