Four people were killed and one was severely injured after a rock fell at Village Main Reef Ltd.'s Tau Lekoa gold mine in South Africa on Dec. 6, Reuters reported.

The incident followed two seismic events, according to spokesperson James Duncan. He said the company will not issue comments until investigations are completed.

The National Union of Mineworkers criticized the company and claimed that a group of workers trained to perform underground rescues did not act quickly enough to save the victims and "deliberately stopped the team leaders and winch drivers from rescuing the four mineworkers."

"There was no escape route in the working area where the four mineworkers were found dead," the union said.