Besides the Incas and Spanish explorers, Chilean and English companies mined the brochantite veins from 1879 to 1912. The opencast was the biggest pit in the world during the 1990s. But it has lost its foremost position and the newer Escondida mine is now the world's largest producing mine with 750,000 metric tons of production which was 5.6% of the world's production in 2000. Copper has been mined for centuries at Chuquicamata as was shown by the discovery in 1899 of "Copper Man", a mummy dated at about 550 A.D. which was found trapped in an ancient mine shaft by a fall of rock. It is also said that Pedro de Valdivia obtained copper horseshoes from the natives when he passed through in the early 16th Century.