The deal, which has been signed with Aristus, comprises an initial $675m payment for a 75% stake in the project and a deferred payment of $225m for the remaining interest.

Aristus is owned and controlled by a consortium of individual investors including Roman Abramovich and Alexander Abramov.

Said to be one of the world’s most significant undeveloped copper assets, the Baimskaya project has potential to become a large scale, low cost, open pit copper mine, KAZ Minerals said.

Kaz Minerals chairman Oleg Novachuk said: “The acquisition of Baimskaya marks the next stage of the transformation of KAZ Minerals.

“The development of this new project in Russia will enable the Group to continue its industry leading growth, delivering both value and volume as the copper market is forecast to enter a period of significant supply deficit.

“Through our successful execution of the Bozshakol and Aktogay projects in Kazakhstan we have built a track record for project execution which makes KAZ Minerals the ideal platform to develop this globally significant asset.”

KAZ Minerals expects the project, which is located in a region identified by the Russian Government as strategically important for economic development, to benefit from state infrastructure development and tax incentives.

With a initial mine life of approximately 25 years, the project is estimated to hold 9.5-million tons of copper and 16.5-million ounces of gold.

The mine is expected to have an average annual production capacity of 2,50,000 tons of copper and 4,00,000 tons of gold, over the first 10 years of operations.

Fluor has completed pre-feasibility study for the Baimskaya project development. During the feasibility study, the development strategy, including financing and potential partnering options will be finalized for the project.

Subject to feasibility study, the development of the mine is estimated to require a capital expenditure of $5.5bn.