Rio Tinto begins restarting Oyu Tolgoi underground operations after seismic event

Oct 30 (Reuters) - Rio Tinto on Friday said it had begun "progressively" restarting underground operations at its Oyu Tolgoi copper mine in Mongolia after completing safety reviews following a seismic event that temporarily halted mining activities.

The miner said a seismic event on October 29 triggered a localised rockfall in a temporary storage area adjacent to the production zone, causing ground vibrations but resulting in no structural damage to the underground cave or operating infrastructure.

Oyu Tolgoi is one of the world's largest known copper and gold deposits and is central to Rio Tinto's copper growth strategy. The miner owns 66% of the project, with the Mongolian government holding the rest.

The miner said three employees sustained injuries, and no fatalities were reported, with two of them continuing to receive treatment for non-life-threatening injuries.

Rio Tinto also flagged delays affecting all vehicles passing through the Ganqimaodu border crossing between China and Mongolia, which have reduced the availability of trucks to transport copper concentrate from Oyu Tolgoi.

(Reporting by Sameer Manekar & Rajasik Mukherjee in Bengaluru; Editing by Shreya Biswas and Maju Samuel)