In 2009, the government negotiated an "investment agreement" with Rio Tinto and Ivanhoe Mines to develop the Oyu Tolgoi copper and gold deposit, the biggest foreign-investment project in Mongolia, expected to account for one-third of Mongolia's GDP by 2020. In March 2011, six big mining companies prepared to bid for the Tavan Tolgoi area, the world's largest untapped coal deposit. According to Erdenes MGL, the government body in-charge of Tavan Tolgoi, ArcelorMittal, Vale, Xstrata, U.S. coal miner Peabody, a consortium of Chinese energy firm Shenhua and Japan's Mitsui & Co, and a separate consortium of Japanese, South Korean and Russian firms are the preferred bidders.