One of the largest open-pit copper mines in the world, the Buenavista del Cobre mine in Cananea produced over 200,000 metric tons of copper in 2012. The mine, opened in 1899, is located approximately 40 kilometers south of the border between Arizona and Sonora, Mexico. The open-pit mine was estimated to contain 26.874 million metric tons of copper reserve as of December 2012.
This mine was the location of a 2014 toxic spill: Toxic spill in Sonora copper mine causes environmental disaster
The ore is refined at an on-site concentrator, which has a milling capacity of 77,000 metric tons/day. The concentrate output is transported to the smelter at La Caridad by rail. Also present are an on-site leaching facility and two solvent extraction and electro winning (SX/EW) plants, with an annual production capacity of 55,000 metric tons of copper cathode.
The active, 2-kilometer-diameter Colorada Pit (top right of image below) is recognizable in this astronaut photograph by the concentric steps, or benches, cut around its perimeter (see larger image). These benches allow for access into the pit for extraction of ore and waste materials.
Water (black) fills the bottom of the pit and several other basins in the surrounding area. The city of Cananea, marked by its street grid, is northeast of the mine workings. A leachate reservoir for removal and evaporation of water pumped from the mine workings is located to the east of the mine (image lower left). The bluish-white color of deposits near the reservoir suggests the high mineral content of the leachate.