Resolution Copper (RCM) is a joint venture owned by Rio Tinto and BHP formed to develop and operate an underground copper mine near Superior, Arizona, U.S. The project targets a deep-seated porphyry copper deposit located under the now inactive Magma Mine. Rio Tinto has reported an inferred resource of 1.624 billion tonnes containing 1.47 percent copper and 0.037 percent molybdenum at depths exceeding 1,300 metres (0.81 mi).[1][2] The proposed mine is one of the largest copper resources in North America.[2] Following the passage of the 2015 National Defense Authorization Act, many Native American and conservation groups oppose the copper mine because it will destroy the area above Oak Flat and around the deposit.[3]