There is no doubt that mining changes the landscape. At Resolution Copper, we’re committed to protecting the land and the water and air surrounding it while we operate and once our work is complete.
Tailings storage – Managing excess material
When the mining process is complete and we’ve pulled copper out of the rock, very fine materials are left over, known as “tailings”. We would transport these tailings and permanently store them in a special facility engineered and constructed to be stable and protect of the environment, even in an earthquake or heavy rain event.
The proposed facility would be west of Superior and north of Queen Valley within the Tonto National Forest. The location was selected after consulting with a panel made up of members of the neighboring communities. Under the current design we will reclaim the tailings facility with vegetation native to the Sonoran Desert, both during operations and after mining is complete.
During the permitting process, which relies heavily on public involvement, alternatives to the proposed tailings design will be assessed based on issues that are important to the community. Depending on the outcomes, the plans for the tailings storage facility may change.
Each of the alternatives will ensure the tailings facility is engineered and constructed for long-term stability and environmental protection.
Subsidence — What happens above the ground
Open pit mining is the way copper mining in the Copper triangle and across Arizona is typically done. Resolution Copper would use an underground mining method called block cave mining. This method has been around for decades and has both environmental and safety advantages, making it most suitable and economical for large, deep ore bodies.
Work stays underground, and there is no open pit or large waste rock dumps, but block cave mining causes “subsidence,” or a slow, progressive sinking of the ground above the deposit. Based on our studies, we believe that after 40 years of mining, the subsidence zone would be between 700 and 1000 feet deep. We would monitor and manage subsidence during and after our operations, so we can minimize the potential impact of our work and preserve important natural features such as Apache Leap.
Because block cave mining is a long established mining method used at 20 mining operations around the world, and historically within the Copper Triangle, there is a wealth of information to better inform and understand subsidence and how to safely manage it.
Reclamation – Bringing the landscape back
Remediation of the historic Magma Mining tailings is essential to reducing our overall environmental impact. To date, Resolution Copper has dedicated more than $30 million to clean up a 130-acre site that once housed a copper concentrator and smelter. From now through 2020, we will spend about $20 million more to complete reclamation work. We continually seek to enhance our reclamation processes by integrating site remediation plans into life cycle planning for the project. Our focus leads us toward innovative ways to ensure that the land we use is available for environmental and societal benefits in future.
Once we complete mining operations at the proposed locations, we would reclaim the site, shaping the land to blend in with the surroundings, planting native vegetation and making sure the land and water are safe. This reclamation work creates good jobs for local people, and we are required by law to put aside money before operations begin, so we, not the taxpayers, foot the bill.
Read about the current smelter-affected soil remediation efforts that are underway.