The accident, which took place on Thursday, was caused by one of the largest tremors ever recorded at El Teniente, with the impact of a 4.2 magnitude quake.

Chilean miner Codelco found a second miner's remains at El Teniente after a severe tremor, raising the death toll from last week's mine collapse to two. Efforts to reach trapped miners continue amid investigations into whether mining activities or natural seismic activity caused the disaster.

Codelco is stepping up its rescue efforts for five workers who remain trapped deep underground at the Chilean state-owned copper company’s El Teniente mine but an official said the workers there may be safe.