During most of Chile's history, from 1500 to the present, mining has been an important economic activity. 16th century mining was oriented towards the exploitation of gold placer deposits using encomienda labour. After a period of decline in the 17th century mining resurged in the 18th and early 19th century this time revolving chiefly around silver. In the 1870s silver mining declined sharply. Chile took over the highly lucrative saltpetre mining districts of Peru and Bolivia in the War of the Pacific (1879–83). In the first half of the 20th century copper mining overshadowed the declining saltpetre mining.