Rio Tinto pauses major Mongolian mine after ‘seismic activity’

Anglo-Australian mining giant Rio Tinto said Friday it had paused operations at a massive copper mine in Mongolia due to “seismic activity”.

Oyu Tolgoi, one of the world’s largest copper and gold mines, is seen as a cornerstone of Rio Tinto’s push to ramp up production of the red metal, used in power grids, data centres and electric vehicles.

Rio Tinto said “seismic activity occurred along a rock fault zone” on Thursday at 6pm local time.

Three workers were injured and there were no deaths, Rio Tinto said.

“Underground operations are currently paused in line with procedure, subject to completion of a safety review,” the company said in a statement.

Rio Tinto’s copper production increased 5% in the fourth quarter of 2025 thanks to the expansion of underground operations at Oyu Tolgoi, which is jointly owned by the company and the Mongolian government.

The mine has been a frequent source of controversy in the past, with locals concerned about environmental damage and the loss of profits overseas.