 Expansion to new underground areas will result in an additional increase of up to 140,000 tonnes per day with a possible increase to 170,000 tonnes per day.As of 2010, the estimated cost of bringing the Oyu Tolgoi mine into production was US$4.6 billion, making it (financially) the largest project in Mongolian history; however, by 2013 costs had ballooned to $10 billion, which caused some concern for the Government of Mongolia, which borrows its 34 percent share of investment from the foreign investors with interest.The mine is said to account for more than 30% of Mongolia's GDP upon completion.