Parliament's portfolio committee on mineral resources is demanding answers from Sibanye-Stillwater's managers on Tuesday after the death of four miners, and the disappearance of at least one more.
"The committee fails to understand why senior mine managers are still in possession of their jobs, with such a track record under their stewardship," said committee chair Sahlulele Luzipo on Tuesday as rescuers scrambled to find the missing miner.
"What exactly do they report to work for, when they fail to deliver on the basic legislative and moral obligation of ensuring the safety of workers?"
Luzipo extended heartfelt condolences to the families, friends and colleagues of those who died at the mine in Westonaria, to the far west of Johannesburg, on Monday and demanded a fast investigation.
The mine said the incident occurred on Monday "after five employees entered an abandoned working area and sadly four out of the five employees passed away.
"A thorough investigation will be undertaken into the incident."
Sibanye-Stillwater spokesperson James Wellsted told News24 the rock face temperature at the space the men entered is around 50 degrees Celsius.
This is common for the depth they work at, and to counter this the mine pushes air through the tunnels with fans to cool it down to a workable 28 degrees Celsius.
The air dissipates through the tunnel network, and to make the flow more focused on working areas of the mine, some tunnel entrances are cordoned off so that air does not escape down there.
The cordons are either heavy plastic sheeting to keep air out of that tunnel and keep it flowing towards functional parts of the tunnels, or metal doors.
He said it was still a mystery why the miners entered that area, except that a safety officer had walked in, but had then walked out again. He did not know whether the safety officer had been interviewed yet, as the priority was to find the missing miner.
Wellsted said it was so hot beyond the cordoned off areas that the miners would have known immediately that they had entered a danger zone.
"We will need to investigate and find out what was going on. Whether [they were there] for work. The point is they didn't follow procedure, they didn't have a ventilation person, they didn't notify their safety people."
He said it was so extreme that even the rescue workers packed themselves with ice and could only spend a few minutes at a time looking because of the intense heat and the effect on their bodies.
"These guys would have felt an immediate difference in heat. They would have known they were not in a working area. They could have succumbed to heat exhaustion or some of the gases," said Wellsted.
The mine would first establish how the four miners had died, and what they were doing in the out-of-bounds zone, before commenting on statements by Parliament or unions, he added.
But Parliament's committee chair said they were concerned that 19 people had died at Sibanye's mines since January 2018, and that nine of those people died in the past two months.
The committee also wants answers from the Department of Mineral Resources.
"Furthermore, the department should hold shareholders accountable for senior management's remuneration packages and the dividends that are shared among them, over the dead bodies of mine workers.
"The committee strongly believes that the high number of deaths at Sibanye's mines is a sign that unusual action should be taken."