The explosion occurred in Loralai district of Balochistan province, 600 km from Islamabad. It was caused by an accumulation of methane gas.
Eight workers were killed instantly and two injured persons were taken to a nearby hospital, officials said.
About 200 men were working more than 600 metres underground when the explosion occurred.
The coal mines in Balochistan have a very poor safety record and dozens have died in accidents in recent years.
Forty-three workers were killed when explosions triggered a collapse in a coal mine in March 2011.