The Mongolian government is discussing possible changes to a 2009 investment agreement for the massive Oyu Tolgoi copper-gold deposit, media reports quoted Mongolia's finance minister, S. Bayartsogt, as saying Tuesday. The 2009 deal gave a 66 percent stake in the multibillion-dollar Oyu Tolgoi project in Mongolia's South Gobi region to the Canadian miner Ivanhoe Mines (Toronto: IVN.TO - news) , in which mining giant Rio Tinto now owns a 48.5 percent stake. The government has the remaining 34 percent stake.