Last Updated Feb 5, 2014 8:19 AM EST
JOHANNESBURG -- South African gold producer Harmony Gold launched a rescue operation on Wednesday to free 9 miners trapped a mile underground after a fire at its Doornkop mine, near Johannesburg.
National Union of Mineworkers Health and Safety Secretary Erick Gcilitshana said an underground “seismic event” caused the miners to be trapped.
The company said it had made contact with eight miners, who had managed to flee to a refuge bay at a depth 1,800 yards. The whereabouts of the remaining nine miners was unknown, a company spokesman said.
Rescue teams were sent underground, but access to the affected area was being hampered by smoke and a subsequent rock-fall, the spokesman added.
South Africa's gold mines are among the deepest in the world.