By David Stanway OYU TOLGOI, Mongolia (Reuters) - Global mining giant Rio Tinto <RIO.L><RIO.AX> will respond to any request from the Mongolian government to discuss its investment in the country's giant Oyu Tolgoi copper-gold deposit, but still expects the original 2009 agreement to be honored. Cameron McRae, Rio Tinto's Mongolia country manager and chief executive of Oyu Tolgoi LLC, the entity running the mine, said he had not yet received any formal notification that the government will seek to modify the investment agreement. "We respect the Mongolian government and when they give us the notification to come and talk we will have those talks," he said ahead of a Sunday ceremony marking the half-way stage of construction on the project. "I think what we are demonstrating is that the investment agreement is a contract, and we're going to honor our commitments and we expect the government to honor its commitments." The landmark 2009 investment agreement on Oyu Tolgoi gave 66 percent of the project to Ivanhoe Mines <IVN.TO>, with the rest remaining in the hands of the Mongolian state.