(CNN) -- Rescuers recovered the bodies of eight workers trapped in a South African gold mine after an underground fire this week, the company said Thursday.
One more worker remains unaccounted for, Harmony Gold Mining Co. said in a statement. The company owns Doornkop mine, where the fire erupted Tuesday.
A day before the bodies were found, emergency workers rescued eight other workers and brought them to the surface of the mine west of Johannesburg.
The miners rescued were unharmed, but will be kept under medical observation as a precaution.
Seismic activity triggered the fire 1,733 meters (5,700 feet) underground, officials said.
The 2.4-magnitude tremor sent a rock tumbling, followed by a series of events that caused the fire, Harmony Gold spokesman James Duncan said.
"The rock fell, damaged a cable, which we think caused a spark, which then ignited something and caused the fire," he said. "Obviously, this is all subject to inquiry."
Access to the affected area was a challenge because of smoke and shaky ground, the company said.
Operations other than essential services have been suspended at the mine.
Mining is the backbone of South African economy.
In the past decade, the industry has contributed just over $213 billion (1.9 trillion rand) to both the country's GDP and export earnings, according to the country's Chamber of Mines.