Mining major Newmont is continuing rescue efforts to reach three workers trapped underground at the Red Chris mine in British Columbia, following two fall-of-ground incidents that have blocked access with as much as 30 m of rock and debris.

The employees, who were working more than 500 m beyond the initial collapse, are believed to be safely sheltering in a MineARC refuge chamber stocked with food, water and ventilation supplies. Additional refuge chambers remain accessible, and the area they are in is considered stable and well-ventilated, Newmont and its joint venture partner Imperial Metals said in statements on Thursday.

Newmont, which holds a 70% operating interest in the Red Chris mine, has deployed specialised drones to assess geotechnical conditions and has begun clearing debris with a remote-controlled scoop transported from its Brucejack mine. Restoration of the underground leaky feeder communication system is under way in an effort to re-establish contact, which was lost after a second collapse further restricted access.

“We are actively assessing all methods and technologies available to restore communication and safely bring our team members to surface,” Newmont said in an update.

The incident occurred on Tuesday in the underground development area of the nonproducing portion of the mine. Production at Red Chris has been suspended while rescue operations continue.

Vancouver-based Imperial Metals, which owns a 30% stake in Red Chris, echoed Newmont’s statements, noting the priority remains the safety of the trapped workers and the rescue teams.

In the same announcement, Imperial released second-quarter production results from the mine.

Red Chris produced 23.5-million pounds of copper and 22 624 oz of gold in the three months ended June 30, a 13% and 81% increase, respectively, over the same period in 2024. The improved performance was attributed to higher ore grades and better recovery, despite slightly lower throughput. For the first half of 2025, copper output was up 25% and gold output up 101% year-on-year.