Mining in the area developed gradually, and did not greatly expand until the railway from Lima to La Oroya was completed in 1893.
The smelter, now the city's main employer, was established in 1922 by the American Cerro de Pasco Corporation, who ran it until 1974 when Cerro was nationalized and became part of the state owned Empresa Minera del Centro del Peru S A, otherwise known as Centromin [REF].