Rio Tinto is on the lookout for pay dirt. Rio Tinto Limited, one of the world's largest mining operations (along with BHP Billiton and Vale), is the Australian half of dual-listed sister companies, with Rio Tinto plc taking up residence in London. Although each company trades separately, the two Rio Tintos operate as one business. Rio Tinto mines iron, copper, uranium, industrial minerals (borax, salt, talc), gold, and diamonds. It also produces aluminum products through Rio Tinto Alcan. The company sells globally, but the majority of its operations are located in Australia and North America.