Mar 18, 2019 · But Rio Tinto predicts that the mine could produce 100m tonnes per year for 40 years. That much iron ore would fetch 7bn at current prices. Bauxite is leading Guinea's current mining growth, with production of gold and diamonds stagnant. Government mining revenue rose from 293m in 2015 to 355m in 2018 on the back of rising bauxite production.