The company acquired Antamina in Peru, the world’s third-largest copper producer. It is majority-owned by BHP Billiton and Glencore.

In 2012, about 45 tonnes of mineral slurry leaked at a pumping station after a joint in the pipeline broke. About 3 tonnes, roughly the capacity of a tanker truck, escaped an area designed to contain leaks, according to Antonio Mendoza, environmental manager of Antamina. More than 200 residents of Cajacuy, a village with no running water or sewage system, complained of headaches, nausea, irritated eyes and nosebleeds more than a week after the spill. 47 were hospitalised. The company claimed the spill was not toxic but according to a company document made public by the Peruvian newspaper La Republica, the mix is “very toxic” and as well as copper and zinc it contained sulphur, arsenic, silica, lead, iron sulphide, and crystalline silica.