DEEPEST IN WORLD
Production at the mine was halted and would remain shut until an investigation had been completed and damage repaired, Briggs said. Harmony is the world's fifth biggest gold producer.
The miners were caught after an air pipe broke off and hurtled down the shaft, damaging steelwork and severing an electrical cable carrying power to the main lift, Briggs said.
The National Union of Mineworkers (NUM) blamed poor safety standards and Harmony's practice of mining 24 hours a day.
"We suspect negligence. Because of continuous operations there is no time to make adequate checks," NUM President Senzeni Zokwana told reporters.
Motsepe said additional measures were needed to protect workers. "Our safety records both as a company and as a country leave much to be desired," he told reporters.
South African gold mines are the deepest in the world and unions have often criticised companies for not doing enough to ensure workers' safety.
Minister of Minerals and Energy Buyelwa Sonjica, who this week visited a mine operated by AngloGold Ashanti
"I would not call it a crisis because mining is risky by nature. But I still think there is room for improvement," Sonjica told reporters at the Elandsrand mine on Thursday.
Gold mine operations have come under scrutiny over the past few months after a series of accidents. Companies are mining ever deeper to reach remaining seams and reap the benefits of a sharply higher bullion price.
"I feel happy to be on the surface. It was hot, dusty and I am quite hungry now," said 27-year-old Zandile Sindiwe.
