The family of one of eight miners trapped by flood waters in a zinc mine in Burkina Faso is still hopeful the workers will be found alive.
“It’s been three weeks of sleepless nights for all of us,” a cousin of one of the trapped men told the BBC.
There has been no contact with them since they were caught by flash floods last month.
It is not known if those working more than 520m (1,706ft) below ground reached two available refuge chambers.
The mine’s Canadian owners say search crews continue to work 24 hours a day.
Specialised equipment has been brought in from Ghana and South Africa to speed up the rescue efforts at the mine in Perkoa, which is about 100km (60 miles) west of the capital, Ouagadougou, and has a depth of 710m.
Trevali Mining says 32 million litres of water have so far been pumped out of the mine, allowing rescue workers to reach 550m below ground.
This is 30m below where the water settled after the heavy thunderstorm on 16 April that cut off electricity and communications.
In less than an hour, 125mm of rain fell – five times the average monthly amount.
According to a rescue worker who spoke to the AFP news agency, a refuge chamber, or what he called a “survival room”, was located at a depth of 580m.
It is not clear when the rescue workers will reach this area.
“We are hopeful, yet angry at the same time,” said Yakouba Bama, whose cousin Charles Bama is one six of Burkinabès missing, along with one worker from Tanzania and another from Zambia.
The case has caused outrage in Burkina Faso as rescue operations only got under way following protests and a sit-in at a government building at a nearby town five days after the floods.
“We don’t know if there’s enough oxygen for them and no-one is supplying them with food,” the cousin said about the family’s concerns.
The government has launched a judicial investigation into the incident and mine managers are not allowed to leave the country.
Trevali CEO Ricus Grimbeek said the firm was working closely with all levels of government and appreciated its support.
“We welcome the decision by the government to move its crisis management committee nearer to the mine site to better include family members of the missing workers and facilitate closer collaboration as we rapidly work to locate the missing individuals,” he said in a statement.
During the rescue efforts a road ramp into the mine has been rebuilt, and 5,000m of new pipes along with more than 24 electric and diesel pumps installed, Trevali says.