RIO TINTO (Minas de Rio Tinto), a mining town of south-western Spain, in the province of Huelva; near the source of the river Tinto, and at the terminus of a light railway from the port of Huelva. Pop. (1900) 11,603. Rio Tinto is one of the greatest copper mining centres in the world; and it is from the discoloration of its waters by copper ore that the river derives its name. Besides the town of Minas, several villages are peopled by the native miners, whose numbers exceed 10,000; and one is occupied solely by British mine officials. The surrounding country is covered for miles with heaps of slag, and has been reduced to a desert. In 1903 the output of the mines included 840,000 tons of copper ore, worth more than £500,000, besides a relatively small quantity of iron and manganese. Almost the entire product is dispatched to Huelva for shipment to Great Britain. Rio Tinto was probably first exploited by the Carthaginians; vestiges of later Roman workings may still be seen. After the Moorish conquest, in 711, it was neglected until 1725, when the mines were leased to a Swede named Wolters. Their modern importance dates from 1872, when a syndicate of London and Bremen capitalists purchased them from the Spanish government for nearly £4,000,000.