Durban, South Africa - Some 955 gold miners were rescued on Friday morning after being trapped underground for more than 24 hours following a power cut.
They resurfaced unharmed, but some were suffering from dehydration and blood pressure issues.
They had been stuck a kilometre underground at the Sibanye Stillwater Beatrix Mine in Welkom for two nights and were finally rescued when the power returned to the mine.
Severe storms on Wednesday had knocked down the power lines in the area, causing an outage at all three shafts at the mine.
Unions are now demanding answers.
The Nation Union of Mineworkers in South Africa (NUM) and the National Union of Metalworkers in South Africa (NUMSA) said the mine should temporarily cease operations.
"The mine should be closed for now until the health and safety measures are put in place," said Livhuwani Mammburu, NUM spokesperson.
"When there is a power failure, generators are supposed to kick in. Our sense is that the generators were not properly maintained and this company seems to be relaxed about health and safety," Mammburu told Al Jazeera.
There were workers working underground with chronic illnesses like high blood pressure and diabetes who didn't have access to their medication for two nights, and you are telling me this is acceptable?
Livhuwani Mammburu, NUM spokesperson
According to local news channel ENCA, the mine had generators, but there were fears they might trip while bringing the miners up.
The mining company reportedly wanted to avoid miners being stuck in cages should the power supply cut.
James Wellsted, Sibanye spokesperson, told Al Jazeera that the miners were technically "never trapped".
Wellsted said miners had the option of walking 4km to an escape shaft that remained operational, but management decided against using this potentially risky route.
"To move such a large group of people underground is difficult and risky and as it turned out, this was the right decision," Welsted said.
South African Chamber of Mines spokesperson, Charmane Russell, told Al Jazeera the incident was safely and competently dealt with.
"We share the concern for those who were delayed underground, and for their families who had to wait for their return.
"But we commend their patience and diligence in following the procedures that are in place to deal with such eventualities," said Russell.
NUM spokesperson Mammburu said employers underplayed the incident.
"There were workers underground with chronic illnesses like high blood pressure and diabetes who didn't have access to their medication for two nights, and you are telling me this is acceptable?" he said.
The National Union of Metalworkers in South Africa (NUMSA) spokesperson Phakamile Hlubi-Majola told Al Jazeera a proper audit was needed to avoid similar incidents.
"They were trapped underground ... it is like being buried alive. We need to analyse how this happened, and if all necessary measures were taken to prevent it.
"Power outages cannot be controlled; it happens from time to time. If they [the company] do not have the necessary equipment, then they should not be allowed to operate."
Mosebenzi Zwane, South Africa's mines minister, will travel to Welkom on Friday to be briefed on the incident.
South Africa has some of the deepest mines in the world, reaching depths of 4km.
Unions have long accused mining companies of poor wages and skimping on health and safety standards.
In August 2017, five mineworkers died when sections of a gold mine collapsed.
There were at least 76 fatalities in South African mines in 2017, following 73 deaths in 2016.
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