Mongolia wants to bring forward the raising of its stake in the Oyu Tolgoi copper project that’s being developed by Rio Tinto Group and Ivanhoe Mines Ltd. to 50 percent from 34 percent, according to the minerals minister. “We have sent the proposal to Ivanhoe to renegotiate the timeframe for us to increase the government stake,” Dashdorj Zorigt told reporters at Oyu Tolgoi yesterday. Such an increase is permitted after only 30 years, according to a summary of the $16 billion project agreement from London-based Rio Tinto.