A drone view shows the entrance to Codelco's El Teniente copper mining complex, after several miners have been reported missing at the Andesita unit following a seismic incident, in Maitenes, Chile August 1, 2025. REUTERS/Pablo Sanhueza

Chilean copper giant Codelco has halted mining at its flagship El Teniente mine and postponed its quarterly results announcement as it continued efforts on Friday to reach five trapped workers following a deadly collapse.

The National Copper Corporation of Chile, known as Codelco, said a “seismic event” on Thursday afternoon caused the accident. The U.S. Geological Survey recorded a magnitude 5 earthquake 17 miles northeast of Machali, where the El Teniente mine is located, at 5:34 p.m. local time.

Rescue teams in Chile are searching for five miners trapped after a partial collapse triggered by a tremor killed one colleague and halted operations at the world’s largest underground copper mine.

Officials say that a worker was killed and five others remain trapped underground after a collapse at a copper mine in Chile