The Thiess-Khishig Arvin Joint Venture (TKAJV) has secured a contract to provide mining services at the Oyu Tolgoi underground project in Mongolia.

Under the three-year contract, TKAJV will be responsible for executing underground ground support and development work, with more than 300 Thiess personnel expected to be involved.

This development marks TKAJV's return to underground mining at the project, following its earlier successes with the construction of the 6.5km twin declines.

Located in Umnugovi province, the Oyu Tolgoi copper and gold underground project began production in 2023 following a $7bn expansion.

The move established the project as a high-performing, integrated copper operation that combines both surface and underground mining.

Thiess executive chair and CEO Michael Wright said: “Securing this contract not only reaffirms our strong relationship with Oyu Tolgoi – it also demonstrates our commitment to excellence in service delivery, and our ongoing commitment to Mongolia, where we have operated since establishing in 2007.

“Our track record of safe and reliable underground performance has been key to earning the trust of our client and stakeholders, and we look forward to building on this success as we re-enter the main mining operations at Oyu Tolgoi.”

Between 2028 and 2036, the project is expected to produce around 500,000 tonnes of copper per annum, enough to manufacture six million electric vehicles.

Currently, Rio Tinto holds a 66% stake in the project while the Mongolian Government owns the remaining 34% interest. Rio Tinto oversees the operation on behalf of the owners.

Open-pit mining at the copper and gold project commenced in 2011, followed by the start of copper concentrate production at the site’s copper concentrator in 2013. The concentrator is said to be the largest industrial facility ever constructed in Mongolia.