Shearman & Sterling has advised Mongolian company Erdenes Oyu Tolgoi on a $4.4 billion financing to expand the country’s massive Oyu Tolgoi copper mine, with Sullivan & Cromwell representing co-owner Rio Tinto, and Milbank, Tweed, Hadley & McCloy counselling the lenders.

Shearman & Sterling’s team was led by China-based partners Matthew Bersani (Hong Kong) and Andrew Ruff (Hong Kong and Shanghai) as well as Tokyo-based partner Etienne Gelencsér.

The Milbank team representing the project’s lender group, including the European Bank for Reconstruction and Development and the International Finance Corporation, as well as Export Development Canada, Export Finance and Insurance Corporation and US Export-Import Bank, and a syndicate of commercial banks was led by London-based Phillip Fletcher.

Located in the southern Gobi desert, the Oyu Tolgoi project is the largest undeveloped copper-gold mine in the world. The Mongolian government holds 34 percent of the mine while Turquoise Hill Resources – in which Rio Tinto has 51 percent stake – owns 66 percent of the mine.

The financing, which is expected to close in early 2016, will help ensure the underground mine’s speedy development. Open pit mining of Oyu Tolgoi started over two years ago, but work was halted amid disagreements over construction expenses and taxes, which were cleared earlier this year.

Oyu Tolgoi is projected to generate around 40 percent of Mongolia's gross domestic product as soon as it goes fully operational.