The government of Burkina Faso said on Friday that rescuers were battling to pump water out of a flooded mine where eight miners had been missing for over three weeks.

When an underground portion of the mine flooded on April 16 due to heavy rain, the eight — six Burkinabe, a Zambian, and a Tanzanian — were reported missing.

The catastrophe occurred at a Trevali Mining mine in Perkoa, about 100 kilometres (60 miles) west of Ouagadougou’s capital.

“The pumping machines that have been set up are operating (too slowly) for our taste, and there is no guarantee on this timescale that we will be able to find them alive as we hope,” said government spokesman Lionel Bilgo, speaking after travelling to the mine on Thursday with a government delegation.

He said that every effort was being made “to find our eight brothers,” with extra equipment and support being brought in from Ghana.

A rescue worker said the hope was that the eight, who had been working at a depth of 700 metres (2,300 feet), had been able to reach a “survival room” located at a depth of 580 metres, which has emergency supplies.

One of the pumps is able to remove 60 litres (16 US gallons) per second, but efforts to lower water levels at a faster rate are being hampered by equipment breakdowns, he said.

According to Antoine Bama, a relative of one of the missing, the rescuers anticipated to reach the survival room on Thursday.

“Sadly this date has gone by” with no news, he said, adding that he still hoped for a “miracle”.