 This is up from 46.5% beforehand.In June 2011 Rio Tinto paid $502 million for 55 million additional shares, increasing its control to 46.5% from 42% (35% prior to that) and giving it an extra seat on the board (up to 7/14), though Rio Tinto was restricted from increasing its stake in the company to a majority before 2012.Since 2006 Rio Tinto invested $3.5 billion in Ivanhoe Mines.