Resolution Copper (RCM) is a joint venture owned by Rio Tinto and BHP Billiton 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). The proposed mine is one of the largest copper resources in North America. Following the passage of the 2015 National Defense Authorization Act, many Native American and conservation groups fear the copper mine will destroy sacred and environmentally sensitive land.
Resolution Copper estimates the $64 billion excavation project would run over 60 years. 
Through 2012 Resolution Copper had invested almost a billion dollars in the Superior project, and planned a $6 billion investment to develop the mine, if the Federal land exchange is approved. Pending approval, the project budget was cut from about $200 million in 2012 to $50 million in 2013.
The company plans to use block caving which creates subsidence. In an undated report, the company splits subsidence into three categories collectively called "surface impact zones". These are intact zone, fracture zone and cave zone. The cave zone would be 1 1⁄2 miles long and over 850 feet deep.
The company has been exploring solutions for the 1.599 billion tones or 19.9 billion cubic feet tailings which will be produced. One possibility is using existing mined out open pits as tailing deposits, a brownfield known as the Pinto Valley mine in Gila County, Arizona or a greenfield site on 12 sections of land on the far northern end of what’s known as Superstition Vistas. The company hopes to have the new mine in production by 2020. The proposed mine might be capable of producing 25 percent of projected future US copper demand for several decades.
As of 2008[update] the project was stalled pending a proposed land swap with the federal government. Resolution Copper has proposed to give the federal government 4,500 acres (18 km2) of environmentally sensitive land in Arizona in exchange for the 3,000-acre (12 km2) proposed mine site, which includes the popular Oak Flat Campground, a protected area since 1955.
In May 2009, Arizona Democratic representative Ann Kirkpatrick introduced legislation in Congress to complete the land swap. The swap then had the support of Arizona's two Republican senators. The swap also has had considerable opposition and may have cost Ann Kirkpatrick her congressional seat in her 2010 loss to Paul Gosar; however, she regained the seat in 2012 and won again in 2014.
In 2013, the proposed land swap was readdressed when Rep. Paul A. Gosar (R, AZ-4) introduced the Southeast Arizona Land Exchange and Conservation Act of 2013 (H.R. 687; 113th Congress). The bill provided that the Apache Leap Cliffs, which rise prominently just east of the town of Superior, remain in federal ownership, and directed the Secretary of the Interior to manage Apache Leap so as to preserve its natural character. The bill required Resolution Copper to surrender any mining rights it has over the Apache Leap cliffs, and deeding 110 acres of private land in the area of cliffs to the federal government.
In December 2014, the United States Congress passed, and President Obama signed the 2015 National Defense Authorization Act, which included the provisions of the stalled Southeast Arizona Land Exchange and Conservation Act. The Act cleared the way for the land swap in which Resolution would receive 2,422 acres of National Forest land in exchange for deeding to the federal government 5,344 acres of private land. The mine would destroy an area set aside in 1955 by President Dwight D. Eisenhower which is sacred to the San Carlos Apache Indian Reservation. Both the Oak Flat Campground, an area dotted with petroglyphs and historic and prehistoric sites, and the steep cliffs at Apache Leap would be affected. In July 2015, a march protesting the land swap arrived in Washington DC.
Native American and environmental groups respond
The San Carlos Apache Tribe, the National Audubon Society in Tucson, the Grand Canyon Chapter of the Sierra Club as well as the National Congress of American Indians have joined in the fight against the Resolution Copper land swap. Native American groups and conservationists worry about the impact to surrounding areas and have led a strong opposition to the land exchange. James Anaya, former United Nations special rapporteur on the rights of indigenous peoples, said that without community and tribal support, Rio Tinto should abandon its Resolution Copper mining project. United States Secretary of the Interior Sally Jewell said she was "profoundly disappointed with the Resolution Copper land-swap provision, which has no regard for lands considered sacred by nearby Indian tribes".
By January 2015, 104,646 people had signed the petition, "We the People|Stop Apache Land Grab". Jodi Gillette, Special Assistant to the President for Native American Affairs, quickly gave an official White House response, vowing that the Obama Administration will work with Resolution Copper's parent company Rio Tinto to determine how to work with the tribes to preserve their sacred areas.
- Resolution Copper Mining LLC reports an Inferred Resource, 29 May 2008 news release
- "History". About Us. Resolution Copper Mining. Retrieved December 15, 2014.
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- Resolution Copper Mining "Letter to the community", November 30, 2012
- BUREAU OF LAND MANAGEMENT lead file AMC60069
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- LAND SWAP THREATENS OUR PUBLIC LANDS, OAK FLAT CAMPGROUND ON THE CHOPPING BLOCK, Arizona Sierra Club
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- staff (23 July 2015). "Resolution Copper: 6 Egregious Examples of Parent Rio Tinto's Rights Violations Worldwide". Indian Country Today Media Network. Retrieved 18 September 2015.
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- ICTMN Staff (January 13, 2015). "White House Responds to 'Stop Apache Land Grab' Petition". Indian Country Today Media Network. Retrieved January 14, 2015.
- Scott Manske & Alex Paul, Geology of a Major New Porphyry Copper Center in the Superior (Pioneer) District, Arizona. 2002, Economic Geology v. 97 no. 2 p. 197-220: Abstract. doi: 10.2113/gsecongeo.97.2.197