From times long predating colonial rule, this region of geological volcanics was known for its rich mineral deposits. During Spanish rule, Cerro de Pasco was treasured for its “plata piña” (0.999 silver) and the mining camp that started in 1630 grew into a significant mining town. During the years following independence (1821) it produced 65% of Peru’s silver and by 1870, Cerro de Pasco was already one of the most cosmopolitan cities in the country, with a local railway, major banks and twelve vice-consulates. After the war with Chile (1890) it played a critical role in funding reconstruction. The arrival of the Cerro de Pasco Corporation in 1902 signaled the start of the largest enterprise in South America by far and until that moment the greatest US investment outside of that country, led by names such as John Piermont Morgan, Henry Clay Frick and Ogden Mills.
In the late fifties the operation switched from underground to open pit, the first in South America and the focus of exploitation shifted from copper, gold and silver to zinc, lead and silver as base metals demand grew worldwide. There was no place on Earth with a higher concentration of metals as diverse as Cerro de Pasco. The Corporation’s investment in the La Oroya Metallurgical Complex gave birth to the most advanced technologies and the highest grades of metals in the world. In 1955 it was the largest employer in the country after the state and paid the best remunerations in Peru. In December 1973, after 72 years of uninterrupted activity, the Cerro de Pasco Corporation was nationalized by Peru’s military Government, led by General Juan Velasco Alvarado. During this period of State ownership, the mine was developed with little regard for the environment or the health of its workers and local communities. The town grew with little formal planning or control around the mining activities and to some extent merged with the mine itself, with little thought given by anyone to the potential negative impacts of living in an industrial area. Under the operation of the state-owned Centromin, the operation went into a final tailspin during the eighties and was finally reprivatized at the end of the nineties.