The remaining 34% is owned by the Government of Mongolia through Erdenes Oyu Tolgoi.
The Australian mining giant initially offered C$34 a share in March this year, but increased it to C$43 per share in cash in August. That was a more than 19% premium to the stock’s end-of-August closing price and a 67% premium from the day before the initial offer was made.
“Given the dearth of copper opportunities elsewhere, combined with its recently lowered risk profile, increasing its Oyu Tolgoi exposure now makes sense,” BMO analysts Alexander Pearce and David Gagliano wrote at the time.
As a result of the transaction, Turquoise Hill will apply to have its common shares delisted from both the Toronto and the New York Stock Exchanges. It will also cease to be a reporting issuer under Canadian securities laws.
Rio Tinto, which has mined copper from Oyu Tolgoi’s open pit for a decade, has said the move will simplify governance, improve efficiency and create greater certainty of funding for the long-term success of the Mongolian operation.
“This acquisition further strengthens our copper portfolio, as part of our strategy to grow in materials the world needs for achieving net zero and delivering long-term value for our shareholders,” Rio Tinto copper boss Bold Baatar said in the statement.
The company will now focus on completing the underground section of Oyu Tolgoi, which will lift production from 125,000–150,000 tonnes in 2019 to 560,000 tonnes at peak output, expected by 2025 at the earliest. This would make it the biggest new copper mine to come on stream in several years.