The families of eight missing miners in Burkina Faso desperately awaited news from rescue teams continuing on Thursday to locate the men who have been stuck underground for 26 days.

There has been no communication with the miners since they were trapped more than 500 metres (1,640 ft) below ground during a flood at Canada-based Trevali Mining Corp's Perkoa zinc mine on April 16.

It is possible that the men reached a rescue chamber stocked with food and water, Trevali said. After pumping water out of the mine for weeks, rescue teams were nearing the chamber on Thursday, a company spokesperson said.

Distraught family members have been meeting each day at the site in central Burkina Faso's Sanguie province for updates and moral support.

"We have hope. We know they will come back. We're really counting on God," said Sylvie Bama, the wife of miner Charles Bama, after a group prayer session near the mine.

"I'm looking at photos of my husband. I miss him a lot. Today it has been 26 days since he left home," she said.

Bama sells used clothing but counts on her husband's income to support their four children. Her husband's brother, Antoine Bama, left his home in the capital Ouagadougou to stay with the family and provide support after the accident.

He tries to stay positive for the sake of his brother's children, ranging in age from about six to 20.

"We have to try to give them hope," Antoine Bama said.

Burkina Faso's Labour Minister Bassolma Bazie said water samples had to be studied for safety reasons before rescuers could go underwater to try to reach the chamber.

"We are organising for rescue teams to dive into the area and do some checks. But to dive in mining waters that have been circulating in the mine, we need to analyse a few samples," Bazie said.