Rio Tinto, the FTSE 100 mining giant, has lifted its shareholding in the Canadian firm Ivanhoe Mines to 49% of Ivanhoe's issued stock.Riot spent £73,075,000 buying 0.5% of Ivanhoe's issued share capital on the 22nd of September, lifting its stake to its maximum under current agreements.Ivanhoe, although head-quartered in Vancouver, Canada is developing a project in Oyu Tolgoi, Mongolia, believed to be the world's largest undeveloped deposit of copper-gold.BS