All five workers trapped in Chile’s El Teniente copper mine after a collapse caused by a 4.2 magnitude earthquake have been found dead, officials confirmed.

The collapse, which occurred Thursday, also killed one miner instantly and injured nine others.

Rescue teams located the trapped miners using GPS but were unable to reach them in time.

Authorities are investigating the cause of the tremor and whether safety protocols were violated, The Guardian has reported.

El Teniente, the world’s largest underground copper mine, is operated by state-owned Codelco, which has suspended operations and launched an internal review.

Written by B.C. Begley