The El Teniente mine is located in the Andes, 80 km south of Santiago. It is one of the eight sites operated by the Chilean state-owned company, Codelco, which extracts Chile’s leading natural resource: copper. Mining operations started at the beginning of the 20th century with the upper levels of the deposit at an altitude of more than 2,000 metres. The method: a tunnel drilled on the side of the mountain to access the Pipa: an area where the ore is crushed from the vast caves before being transported by rail to the extraction facilities. When resources at one level are exhausted, the access tunnels are mined and the mining moves to lower levels. This is the context in which the New Mine Level project was launched in October 2011. Projecting that the mine level would be depleted in 2018, Codelco started building two new 9 km tunnels, one for workforce access and the other for haulage.