RIO TINTO (

MINAS DE RID 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 . (19o0) 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 xo,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 84o,000 tons of copper ore, worth more than £500,000, besides a relatively small quantity of iron and manganese . Almost the entire product is despatched 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 .