Rescuers in northern Turkey have been pumping air into a mine to save workers trapped underground.
The miners are believed to have been confined 540m (1,770ft) below the surface following an explosion.
Hundreds of people are helping to remove earth and rocks that are blocking access to the mine.
The blast - at the state run Karadon mine near the Black Sea city of Zonguldak - is believed to have been caused by methane gas.
Turkey's labour minister, Omer Dincer, told a local television channel that it was not clear how long it is going to take to reach the miners because the extent of the cave-in was still unknown.
"We have heard that there are areas inside unaffected by methane. We hope our workers are there," the minister said.
Relatives of miners have been waiting near the entrance for news about their loved ones trapped inside.
Initial attempts to reach the miners through the main shaft faced a setback when it was found that the entrance was severely damaged by the blast.
Rescuers had to use another entry point nearly 2km (1.2 miles) away from the site of the explosion.
Monday's accident is the third incident in a Turkish mine in six months. In February, a methane gas explosion at a coal mine in the north-west killed 13 workers.
Analysts say the safety record of Turkey's coal mining industry lags behind that of most industrial nations.
The country's worst mining disaster was in 1992, when 270 miners were killed near Zonguldak.