Rio Tinto is an Anglo-Australian multinational and the world's second largest metals and mining corporations, behind BHP Billiton, producing iron ore, copper, diamonds, gold, coal and uranium.
The company was founded in 1873, when a multinational consortium of investors purchased a mine complex on the Rio Tinto, in Huelva, Spain, from the Spanish government.
Since then, the company has grown through a long series of mergers and acquisitions to place itself among the world leaders in the production of many commodities, including aluminium, iron ore, copper, uranium, and diamonds.
Although primarily focused on extraction of minerals, Rio Tinto also has significant operations in refining, particularly for refining bauxite and iron ore.
The company has operations on six continents, but is mainly concentrated in Australia and Canada, and owns its mining operations through a complex web of wholly and partly owned subsidiaries.
According to en.wikipedia