Eight of the deceased workers were Murray & Roberts employees subcontracted to the mine.

  Thursday's accident brought to 14 the number of deaths at Gold Fields' mining sites this week.

  Gold Fields said the accident happened while workers were being taken from level 105 to level 110.

  Nick Holland, who officially commenced his duties as Gold Fields' new chief executive on Thursday, described this week as tragic for his company.

  "It's a disastrous day for Gold Fields. It's a black day, very distressing for us," he said.

  The accident has led to the suspension of operations at Gold Fields' three mining sites, including the Driefontein mine, where four workers died in a seismic-related rockfall on Tuesday.

  Also on the same day, a fifth miner was killed at Twin Shafts when a rock fell while he was drilling.

  Gold Fields said the mines would remain closed until it was safe to resume work.

  The department of minerals and energy said it would launch its own investigations into all fatal accidents at the mines.

  Quizzed on the details of the accident, Holland said he did not want to pre-empt the out-come of the investigation, saying only that there had been an "apparent failure" with the conveyer chain.

  Gold Fields also revealed that the same chain that broke and led to the accident had been inspected the previous day.

  This week's spate of accidents at Gold Fields mines has angered labour unions, who condemned the mine's safety standards.

  "There is a serious problem here - 14 workers in just a week.

  "This has gone too far," said Solidarity spokesperson Dirk Hermann.

  "There's going to be a technical inspection, but we will be calling for another independent and much deeper inspection at Gold Fields mines.

  "It needs to be determined if safety in this company is more important than production."

  National Union of Mineworkers regional chairperson Thamsanqa Joko accused Gold Fields of compromising workers' safety.

  "We feel that more should have been done to improve safety conditions. Gold Fields is not doing enough to protect workers," he said.

  A sombre atmosphere engulfed the mine on Thursday, with workers speaking in hushed voices.

  A visibly distraught miner, who requested not to be named, expressed his anger at Gold Fields, saying it was "impossible for such a thick chain" to break if it had been properly serviced.

  "It is very thick. It can fill two hands together. How can it just break like that?

  "This accident could have been prevented if things had been done the right way," the visibly furious miner said.

  Miners said the chains were supposed to be checked at least once a week, and replaced if necessary.