1-158-750 - Oxford Science Archive/Heritage Images

Mount Potosi, Bolivia, c1788. In 1545 one of the world's richest silver deposits was discovered at Mount (Cerro) Potosi in what is now Bolivia. The Spanish conquistadors at first used native labour to exploit the silver, but by the early 17th century they were importing slaves from Africa. Life in the mines was brutal and short, and in the smelter the workers breathed in mercury vapour. It is estimated that between 1545 and 1825 some 8 million African and native South American workers died in the mines. The refined metal was taken to the west coast, now Chile, where it was loaded into galleons and carried to Europe to finance the Spanish empire. On the right is a wind-powered stamping mill for processing ore. From New ... System of Universal Geography by Thomas Bankes. (London, c1788).