Mining giant Rio Tinto sold its interest in a coal mine in Australia for A$1 as the commodity market continues to struggle. The mine was sold for less than the price of a cup of coffee, the Financial Times reported on Monday. Rio Tinto’s new chief executive said he wants to grow the company by building and buying assets and expanding its net for commodities for the company to grow. The minerals industry is seeing a downturn in world commodity markets which has extended into its fifth year. Thermal coal prices have fallen from about $180 per tonne in 2008 to just over $50 due to overproduction and a drop in demand from China.