Resolution Copper

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. Which is what will happen as soon as they collapse all the tunnels near Oak Flats, AZ. This will completely destroy the entire mountain, including the sacred land to the native tribes of Oak Flats.

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.

Resolution Copper also owns the mineral rights acquired from ASARCO to the Superior East deposit which is another deep seated porphyry deposit within a mile to the east.

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.

...
Wikipedia