Rescue workers are using huge pipes to pump water from 350m underground, but energy minister Taner Yildiz said on Thursday that the operation is being hampered by mud and damage inside the mine.
There has been no contact with the 18 men since they were trapped on Tuesday amid surging waters in the Has Sekerler mine near the town of Ermenek in Karaman province. Officials say their chances of survival are slim unless they managed to reach a safety gallery.
Yildiz says, "hope regarding our 18 brothers is decreasing".
The tragedy has renewed questions about Turkey's poor workplace safety.