Officials at Canada-based Trevally Mining Corp said the company was caught unawares last month of torrential rains during the dry season in Burkina Faso, causing eight people to go underground at its Perco zinc mine.
Rescue efforts have been on since the April 16 floods, but there has been no contact with the missing miners and it is not known whether there were any survivors.
“Given the dry weather, we don’t expect rain and we had all but torrential downpours,” said Hen Frey, vice president of operations at Trevally. He said the water crossed a bridge and broke security barriers.
“It is not only us who are affected, it is also the communities around us that are completely affected by the unexpected rain,” he said in an interview with Reuters on the site.
The company immediately sought help and the next day other mining companies in Burkina Faso sent rescue teams and pumps, Frey said. Water is still being extracted from the mine.
The company said most workers were able to evacuate safely, while eight missing were below level 520, which is 520 meters (1,706 ft) above the surface at the time of the flood.
Below that level are two security chambers with food and water, but it is not known whether any of them were able to reach them.
“There’s always hope, but we also have to be realistic,” Trevally CEO Rickus Grimbeck said in a separate interview with Reuters.
“Those chambers are not designed to be submerged in water. The chambers are designed for ground-fall accidents and toxic environments like smoke,” he said.
The company and Burkina Faso’s government have launched an investigation into the cause of the accident.
“We need to understand … what we need to do in the future so that what happened here never happens again,” Grimbeck said.