SANTIAGO, Aug 3 (Reuters) - All five workers at Chile's El Teniente copper mine who were trapped in a collapse last week have been found dead, miner Codelco said on Sunday, as it vowed to investigate the cause and improve safety measures.

SANTIAGO (Reuters) -Chilean copper miner Codelco on Sunday said two more workers trapped at its El Teniente mine were found dead, bringing the toll of fatalities from a collapse last week to four.

Codelco says four of the five workers trapped at its El Teniente mine have been pronounced dead, as rescue efforts continue following a powerful tremor that caused the mine to collapse last week.