The miners were reportedly working to address safety issues when the explosion took place.
The entrance of the mine was severly damaged by the explosion, injuring five people outside, the emergency situations ministry said.
Three women who were operating the elevator shaft were hospitalised with serious burns.
Relatives of those trapped have been waiting at the mine's administration building to gain news of their loved ones.
The mine was opened in 1958 and is one of the oldest in Ukraine.
It was closed down on Saturday due to safety violations and a vastly reduced number of staff from usual were working at the time of the blast.
Ukraine has a poor mine safety record, with 20 mines being closed temporarily following the deaths of 11 people in a mine explosion last month.
In November 101 miners were killed in a gas blast at the Zasiadko mine in Donetsk.