The underground project is an expansion of the existing Oyu Tolgoi mine in Mongolia, which has been producing through open pit operations since 2013


The Oyu Tolgoi underground project in Mongolia. (Credit: Rio Tinto)

Rio Tinto has commenced production from the Oyu Tolgoi underground project in the Gobi Desert in Mongolia, which has involved an investment of over $7bn.

A ceremony to mark the milestone was attended by Mongolian Prime Minister Luvsannamsrain Oyun-Erdene and Rio Tinto chief executive Jakob Stausholm.

Rio Tinto holds a 66% stake in Oyu Tolgoi, while the remaining 34% is held by Erdenes Oyu Tolgoi, on behalf of the Mongolian government.

In January 2022, the parties ended a long-running dispute over the project and reached an agreement to reset their relationship and proceed with the Oyu Tolgoi underground expansion.

Rio Tinto said that 30 drawbells have been blasted and copper is currently being drawn from the underground mine.

Oyun-Erdene said: “I am proud to celebrate this major milestone with our partner Rio Tinto as we look towards Mongolia becoming one of the world’s key copper producers. The start of underground production at Oyu Tolgoi demonstrates our ability to work together with investors in a sustainable manner and become a trusted partner.

“The next phase of the partnership will enable the continued successful delivery of Mongolia’s ‘New Recovery Policy’ and Vision 2050 economic diversification strategy. Mongolia stands ready to work actively and mutually beneficially with global investors and partners.”

The Oyu Tolgoi underground project is an expansion of the existing Oyu Tolgoi copper and gold mine, which has been producing through open pit operations since 2013.

Through both open pit and underground operations, the Mongolian project is estimated to produce nearly 500,000 tonnes of copper per annum on average from 2028 to 2036. This will be adequate copper to help produce nearly six million electric vehicles annually.

The expansion project will result in an average of about 290,000 tonnes over the reserve life of nearly 30 years at the mine.

Ore from the underground project is presently being processed from Panel Zero in Hugo North Lift 1. Production is expected to be ramped up over the coming years, said Rio Tinto.

Stausholm said: “We are starting underground production 1.3 kilometres beneath the remote Gobi desert from an ore body that will be critical for global copper production and Mongolia’s ongoing economic development.

“The copper produced in this truly world class, high technology mine will help deliver the electrification needed for a net zero future and grow Rio Tinto’s copper business.”