Authorities believe the workers remain trapped inside; rescuers crawl through Rasuwagadhi tunnels to locate them.
It is six days since devastating #mudslides struck the border region between Nepal and Tibet.
Authorities have confirmed that more than 800 people have died in the flash floods, while more than 3,000 remain missing.
Among those unaccounted for are hundreds of workers at hydropower projects across Nepal.
Authorities say 933 hydropower workers are currently missing. Mud and debris block many tunnels, trapping many workers.
Rescue teams are working to reach them, as hopes of finding survivors begin to fade.
