Sidley Austin and Milbank, Tweed, Hadley & McCloy have advised an Indonesian investor group including Medco Energi on its $2.6 billion acquisition of an 82 percent stake in Newmont Nusa Tenggara, which operates Indonesia's second-biggest copper and gold mine. 

Newmont Nusa Tenggara is a subsidiary company of U.S. mining company Newmont, which was represented by Hiswara Bunjamin & Tandjung, Herbert Smith Freehills’ Indonesian associate firm. 

The Indonesian group, led by Amman Mineral Internasional, is buying 56 percent of Newmont Nusa Tenggara from Newmont, and Japan's Sumitomo Corp and its partners. It will buy the remaining 26.2 percent from local companies. Newmont will get $920 million when the deal closes and $403 million triggered by higher copper prices and mine developments, according to Reuters.

The Sidley Austin team on the transaction was led by partner Charlie Wilson. Amman Mineral Internasional was represented by Milbank.