The Perkoa mine, owned by Canadian firm Trevali Mining Corp (TV.TO) and located about 120 km west of the capital Ouagadougou, was suddenly flooded on April 16 after unexpected heavy rain during the country’s dry season.
During the month-long search and rescue operation, there was little hope that the missing men could reach the rescue chamber, which is stocked with food and water and is about 570 meters underground.
“Rescue teams have opened the shelter cell, unfortunately it is empty,” the government news service said in a social media post.
Trevali said the sanctuary cell was found intact and it is now clear that none of the eight missing workers made it to it.
“This is devastating news and we would like to extend our deepest condolences to the families and friends of our colleagues during this difficult time,” said Rikus Grimbek, President and CEO of Trevali.
“We will continue our search efforts and reaffirm our commitment to working at full speed to find our colleagues.”
Distraught relatives of the missing men gathered daily at the scene in Sangui province, seeking comfort from one another as they agonized over the news.
In Africa, fatal accidents are common. The Percoa flood attracted more attention than many others because of the hope, however distant, of an outcome similar to the dramatic 2010 rescue in Chile of 33 miners who spent 69 days underground but did not materialize.
Both the company and the government launched an investigation into the causes of the disaster. The prime minister said on May 2 that mine managers are prohibited from leaving the country.
The Percoa mine consists of an open pit with underground shafts and galleries below. Most of the workers who were there at the time of the flood managed to escape, but the missing eight were in more than 520 meters (1,706 ft) of water.
Six of the missing men are citizens of Burkina Faso, one from Tanzania and one from Zambia.
With many in Burkina Faso asking why it took so long to get to the rescue chamber, and criticism of the company and government emergency services mounting, Trevali said the technical challenges were huge.
The force of the flood was such that it washed away the road leading to the mine, and also disrupted the power supply. Before a full-scale search could begin, the road had to be refilled and power restored.
Initially, the equipment was lowered on foot, but vehicles were required to install equipment capable of pumping water from a depth of less than 500 meters.
Rescuers pumped out about 55 million liters of flood water from an estimated 165 million liters that passed through the underground part of the mine.