Correctional Services said that “matters are under control” at Johannesburg’s Sun City Prison on Wed.
Mine safety has returned to the spotlight in recent weeks following accidents including fatalities at some of the country's 700 mines.
This focus follows and incident in which more than 3000 miners were trapped underground for more than 40 hours at Harmony Gold's Elandsrand mine last week. The miners were all rescued.
Minister of Minerals and Energy, Buyelwa Sonjica announced after the incident that the Elandsrand mine would be shut for six weeks.
Earlier this month, a miner was killed in a tremor at Goldfield's Driefontein mine.
Again, on Wednesday three miners died at Goldfield's Kloof mine after a rope holding a loaded skip broke, resulting in the skip rolling back and hitting the workers, killing them instantly.
The National Union of Mineworkers (Num) threatened to embark on a one-day strike over mine safety.
"We are considering this, to make the industry aware that we are serious about safety standards in the mines," said spokesman Lesiba Seshoka.
Seshoka said so far 160 miners had died on duty this year in South African mines. Last year saw 199 fatalities.
Government spokesman, Themba Maseko said yesterday the government was speaking to stakeholders in a bid to establish an industry safety audit.