Eight of the nine gold mineworkers trapped underground in a shaft west of Johannesburg have been found dead, the National Union of Mineworkers said Thursday.
"Eight of the nine mineworkers who were missing at Doornkop Mine are found dead," the union said in a statement. A search was ongoing for the ninth man still missing.
The union said the bodies were discovered on Wednesday night by rescue teams.
Initially 17 workers were trapped underground after a fire broke out about 1.7 kilometers (over a mile) beneath the surface at mining firm Harmony Gold's Doornkop operations late Tuesday, in an accident that may have been triggered by a seismic event.
Eight of the workers were rescued on Wednesday morning after escaping to a refuge chamber.
The union said the damage to electric cables had triggered a fire underground after a rock fall.
Despite efforts to reduce fatalities, accidents are still common in South Africa's ultra-deep gold mines.
One hundred and twenty eight people were killed in 2010, according to the latest figures published by local NGO Miningsafety.co.za.