The worst South African mining accident in almost five years has left eight miners dead and rescuers searching for at least one more worker. The accident occurred after a fire and rock slide at a Harmony Gold mine in Doornkop, (near Johannesburg, South Africa) Tuesday evening. According to a report on CNN.com the tragic news comes one day after rescuers were able to save eight other miners:

“A day before the bodies were found, emergency workers rescued eight other workers and brought them to the surface of the mine,” CNN reported. “The miners rescued were unharmed, but will be kept under medical observation as a precaution.”

The tragedy occurred late Tuesday evening, according to the National Union of Mineworkers (NUM) and Harmony, after an earthquake reportedly damaged ventilation and water pipes as well as power cables, causing the fire and rock slide to be unleashed.

“The seismic event created the fall of ground, which in turn damaged the cable, which sparked the fire,” Chief Executive Officer Graham Briggs told Bloomberg.com in a telephone interview. “The fire is what’s the dangerous thing because it contaminates the atmosphere: gases and smoke.”

Mineral Resources Minister Susan Shabangu released a statement regarding the tragedy, promising a full investigation into the gold mine mishap:

“The situation is deeply regrettable,” Shabangu said in a statement. “We must ensure that we do all we can to get to the bottom of what caused this incident in order to prevent similar occurrences in future.”

But before any investigation can take place, rescue workers are focused on finding the last missing Harmony worker. Following that, search and rescue teams will turn their attention to the fires themselves, ensuring they are no longer a threat. South Africa’s Department of Mineral Resources told Bloomberg, “The fire may still be causing the release of gases by the end of the week, delaying the inspection.”

As terrible as this horrific incident is, it could have been far worse at according to James Duncan, spokesman for South African mine operator Harmony Gold. He told NBC News that Doornkop employs 3,800 workers, but “there were just 140 people in the mine at the time of the incident as it happened on the late shift.”

South Africa lays claim to some of the world’s richest and deepest gold mines. The last accident in South Africa of this magnitude occurred in 2009 when 82 illegal workers went down a mine shaft and died of suffocation.