Workers at Harmony Gold's Kusasalethu mine were not formally told about the closure of the operation, a worker's representative said on Wednesday.
"According to law, a person must get a notice in a period of 30 days to leave the area if they must leave, and that did not happen here," Paul Motaung claimed.
"They [have] now closed everything, even the water. We can't drink water."
Police and security guards prevented more than 500 mineworkers from returning to the mine's hostels on Tuesday night, he said. Around 50 people were outside the hostels, in Carletonville, on Wednesday.
The company said it had suspended operations at Kusasalethu and was deciding whether to permanently close the mine, which could cost about 6000 workers their jobs.
It cited concerns about unprotected strikes and illegal industrial action, violence, sit-ins, and vandalism of mine property. In the past quarter there had been five sit-ins at the mine.
Business Day reported that the mine was expected to report a cash operating loss of R150 million for the December quarter, and a negative cash flow of R252m.
"Until such time as the unions and Harmony have consulted and agreed on a long-term solution to operate the mine safely and profitably, we cannot give an indication as to when the mine will re-open," company spokeswoman Marian van der Walt said in a statement.
Motaung said the miners were camping outside the hostels because they wanted to talk to management.
"We will camp here until that further notice.... We want to sit [around] the table with management and tell them what we want and they must tell us what they want and not want."
The workers outside the hostels wanted to work and accepted management's reasons for closing the mine.
"If they are dissatisfied with the production, let's discuss what causes that."
On Tuesday, Harmony spokeswoman Henrika Basterfield said there should be no one at the mine because it was closed.
"All I can say is the mine is closed. Only about a 100 people came to the mine two days ago. Transport was arranged for them to go back home."
She said that of the 100, only seven had produced employee numbers on request and were given transport home. The others refused to show their numbers and were not helped.
Basterfield said workers were told on December 21 and 31 that the mine would be closed.
"Only that little group came after people were notified about the closure."