Two people were killed and one was injured on Saturday in a mine accident in South Africa's central Free State province, news agency Sapa reported, according to Reuters. Sapa quoted President Steyn Mine executive Gerrit Kennedy as saying the accident in the gold mine may have been caused by earth tremors in the area. "The accident occurred at 11am on Saturday. The cause of the accident is being investigated but it is suspected that seismic activities in the area caused a collapse of ground at Shaft One," he said. The President Steyn mine belongs to Toronto-listed Thistle Mining Inc.