During Colonial times (1535-1821) gold was produced mainly from placers, silver from the Hualgayoc, Cerro de Pasco, Castrovirreyna, and Cailloma districts, and mercury from the Huancavelica district. After a long period of stagnation following the wars for independence, Peru's mining industry started to prosper during the turn of the century, furthered by Peruvian and foreign mining geologists, engineers, and entrepreneurs. Particularly successful was the mining development within the area of influence of Cerro de Pasco Copper Corporation's La Oroya smelter in central Peru.After World War II Peru's mineral industry blossomed under the Mining Code of 1950 due primarily to sizeable foreign investments, but also due to the development of the local medium-sized mining industry. Extensive exploration led to the discovery and development of many ore deposits, especially the porphyry copper deposits of southern Peru and a number of vein, skarn, metasomatic replacement, and hydrothermal sedimentary deposits of precious and base metals.Peru's mining development has slowed drastically since 1968 as a consequence of nationalization of foreign enterprises, more restrictive mining regulations, and terrorism. Despite these setbacks, significant contributions have been made to the geologic knowledge of the country by foreign government missions, academicians, and consultants, as well as by Peruvian geologists. These studies have documented the geology and geochemistry of many ore deposits and highlighted the potential for additional discoveries and development of diverse mineral resources using modern techniques.