A prosecutor investigating the accident in Chile that left 33 miners trapped underground for more than two months has failed to find anyone responsible.
Authorities had investigated the collapse on 5 August that buried the miners for 69 days at approximately 700 metres underground in Chile's Atacama region. The miners' rescue in a special capsule was followed live around the world.
The Atacama prosecutor said he was closing the case because he could not find enough evidence to press charges against either the owners of the mine or regulators.
Former mining minister Laurence Golborne, who was in charge of the rescue operations, expressed disbelief at the decision, the BBC reports.
He told Chilean radio Cooperativa that regulators had ordered the owners of the century-old mine to build an emergency exit, but they did not comply.
Mr Golborne said that if the measure had been implemented the miners "would not have spent 70 days trapped".
The miners have filed a civil lawsuit accusing the National Service of Geology and Mining of negligence and demanding $US500,000 in damages for each miner, AFP reports. The suit says the state agency had failed to inspect working conditions and mine safety.
The San Jose gold and copper mine, which had been in operation for more than a century, remains semi-abandoned.