TSX-listed Trevali Mining said on Monday that it had not yet been able to locate any of the eight underground workers who went missing when the Perkoa mine, in Burkina Faso, flooded three weeks ago.
There has been no communication with the missing individuals since April 16.
"We are working in solidarity with all levels of government and as fast as we possibly can using all available resources in the country, as well as importing additional machinery and equipment to assist with locating our missing colleagues," president and CEO Ricus Grimbeek said.
"Our thoughts are with our colleagues' families, and we continue to work closely with the families and the government to ensure their needs are met during this difficult time."
The search effort requires the careful rebuilding of the road on more than 5 000 m of underground decline ramp in order to facilitate the search efforts and safely install and operate pumping and piping infrastructure to remove floodwater.
To date, about 25 000 t of waste rock has been used in rehabilitation of the mine access ramp; 5 000 m of new poly pipe has been welded and installed in addition to the existing pipes and more than 24 electric and diesel pumps have been installed and put into operation.
About 32-million litres of water have been removed from the mine and access has been restored to Level 550. The full extent of required mine rehabilitation efforts would become known as dewater progresses to the bottom of the mine at Level 710.