Rio Tinto owns 100 per cent of Kennecott Utah Copper (KUC) which operates the Bingham Canyon mine, Copperton concentrator and Garfield smelter complex near Salt Lake City, US. Its Bingham Canyon copper mine is one of the largest and longest-running mines in the world, it operates state-of-the-art smelting/refining facilities recognised as the world's best for environmental protection practice and achievement, employing about 1,400 people. Large scale underground mining is expected to extend the mine's life by 15 years after open pit reserves are exhausted around 2013. KUC supplies more than ten per cent of United States refined copper requirements and is the third largest copper producer in the US. Substantial amounts of gold, silver and molybdenum are produced as by-products.