Rio Tinto launches corruption inquiry at Oyu Tolgoi

Bloomberg News | October 27, 2025 | 10:46 am Regulatory Issues Top Companies Asia Australia Copper Gold

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The underground expansion of Oyu Tolgoi is Rio’s most important growth project. (Image courtesy of Turquoise Hill.)

Rio Tinto Group subsidiary Oyu Tolgoi LLC is conducting an internal investigation into allegations of corruption and unethical conduct at its copper operations in Mongolia and has sought help from law enforcement.

“We are aware of allegations involving procurement-related activities, and conducting a comprehensive internal investigation, and have sought cooperation of law enforcement authorities,” Oyu Tolgoi said in a statement on social media. “As the investigation is ongoing, we are unable to provide further comment at this time.”

Rio owns 66% of Oyu Tolgoi LLC and operates the underground deposit, which it plans to make the world’s fourth-largest copper mine by 2030, with the Mongolian government holding the remainder. The site is one of Rio’s biggest and most valuable growth assets and while production soared 78% over the last quarter, development has been marred by year’s of political turbulence, cost overruns and delays.

Copper is pivotal to the Rio’s goal of reducing its reliance on iron ore while increasing exposure to the red metal used in electrification — demand for which is set to soar due to the energy transition and rise of data centers.