Yanacocha (Cajamarca Quechua: yana = "black, dark", qucha = "lake, puddle, pond, lagoon") is a gold mine in the Cajamarca region of the Northern Highlands of Peru. Considered to be the fourth largest gold mine in the world, it produced 0.97 million ounces of gold in 2014. The 251-square kilometer open pit mine is situated about 30 kilometers (14 km straight line) north of Cajamarca, in high pampa, straddling the watershed. The operation is a joint venture between Newmont Goldcorp (51.35% ownership), Compañia de Minas Buenaventura (43.65%) and the International Finance Corporation (5%). Mercury spilled by the mining company has poisoned hundreds of people living near the mine and contaminated local water sources. Thousands of local residents have protested the mine in an environmental conflict that also includes ongoing lawsuits against the mining companies. Environmental defenders opposing the mine have been killed and others have received death threats. Overview, background Yanacocha gold mine is located in the province and department of Cajamarca Region, about 800 kilometers northeast of Lima, Peru in the Northern highlands at 3,500 and 4,100 meters above sea level. It operates in four primary basins and is the largest gold mine in South America. Since 1999 it is a joint venture between Colorado-based Newmont Mining Corporation (51%), Buenaventura (44%) and the World Bank Group's International Finance Corporation (5%). Geology Gold in the area was obviously known of by the native Quechua people since their name for a local river is Corimayo, or "gold river." During his 1859 expedition to Yanacocha, Ramandi noted, "These mines they know by the name of Carachugo, and they are in a porous quartz rock, their tunnels are very long..." In 1962 the Guggenheim Bros. ASARCO filed three claims following their discover of the Michiquillay porphyry copper deposit in 1957. In 1968 Nippon Mining drilled 13 exploration wells. From 1970 to 1971, the British Geological Survey included the Yanacocha District in their reconnaissance survey, which showed the district contained a significant silver anomaly. This led CEDIMIN, a joint venture of BRGM and Compania de Minera Buenaventura, to acquire the mineral concessions in the district. Trenching in 1982 confirmed significant silver. Newmont Mining Corporation became the operator of the joint venture in 1985 after a site visit in 1983 and 25 drill holes were made in 1984. Exploration from 1985 to 1993 determined Yanacocha was an 18 km by 6 km northeast trending belt