The company which owns the prospecting rights to the abandoned mine in which at least 30 "illegal miners" were trapped says heavy rain may have been a trigger for the shaft's collapse.
Chinese-owned bullion producer Gold One owns the prospecting rights to the abandoned gold shaft, however was not currently working in it.
"The illegal miners have dug a tunnel right next to it to access the shaft and it has collapsed behind them," Gold One spokesman Grant Stuart said.
Emergency services in South Africa have been using a crane to shift a large concrete slab obstructing the shaft.
More top news
The best of the sunshine will be in the east.
The British territory will allow only domestic partnerships after senators approved the Domestic Partnership Act by an 8-3 vote.
More than 1,500 people are expected to attend the multi-faith service, including many bereaved families and survivors.