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Rio Tinto Begins Restarting Oyu Tolgoi Copper Mine After Seismic Incident
Rio Tinto has begun progressively restarting underground operations at its Oyu Tolgoi copper-gold mine in Mongolia following an October 29 seismic incident that injured three employees. The company also reported transport delays affecting copper concentrate shipments to China.
By Paul Ploumis
Originally published: October 29, 2026
Updated development: October 30, 2026
Key Points
- Mining operations: Underground activities are progressively restarting following safety reviews.
- Incident: Seismic activity on October 29 caused ground vibration and a localized rockfall.
- Employee safety: Three employees were injured; no fatalities were reported.
- Mine infrastructure: Rio Tinto reported no structural damage to the underground cave or operating infrastructure.
- Logistics: Delays at the China-Mongolia border have reduced truck availability for copper concentrate transport.
MONTREAL (Scrap Monster): Rio Tinto has begun progressively restarting underground operations at its Oyu Tolgoi copper-gold mine in Mongolia after completing safety reviews following a seismic incident that temporarily halted mining activities.
The October 29 event caused ground vibration along a rock fault zone and a localized rockfall near the underground production area. Three employees sustained injuries, although no fatalities were reported.
Underground Operations Resume Following Safety Reviews
Rio Tinto initially paused underground operations as a precaution following seismic activity at approximately 6 p.m. local time on October 29.
In an October 30 update, the company confirmed that the incident caused a localized rockfall confined to a temporary storage zone adjacent to the production area.
Rio Tinto said there was no structural damage to the underground cave or its operating infrastructure, allowing operations to begin a progressive restart after safety reviews.
Two employees continued receiving treatment for non-life-threatening injuries, while the company said it was working with relevant authorities and supporting affected employees and contractors.
Oyu Tolgoi Remains Central to Rio Tinto's Copper Strategy
Oyu Tolgoi is one of the world's largest known copper and gold deposits and an important component of Rio Tinto's long-term copper growth strategy.
Rio Tinto holds a 66% ownership interest in the project, while the Mongolian government owns the remaining 34%.
China-Mongolia Border Delays Affect Copper Concentrate Transport
Separately, Rio Tinto reported delays affecting vehicles passing through the Ganqimaodu border crossing between China and Mongolia.
The disruption has reduced the availability of trucks used to transport copper concentrate from Oyu Tolgoi, creating an additional logistical challenge for the operation.
The reported transport constraints are distinct from the underground seismic incident. Rio Tinto's announcement of the progressive restart did not provide a revised copper concentrate shipment schedule or quantify any resulting production losses.
Original reporting courtesy: www.miningweekly.com.
October 30 operational update: Rio Tinto company announcement.
