Around 160 workers were on shift at the state-owned Xialiuchong Coal Mine in Hengyang city, Hunan province when the blast went off, but only 35 were underground. The 40-year-old mine employs over 500 people.
The explosion took place after sparks from machinery ignited flammable gas that had filled the mine.
The mine was legally registered but the local government had suspended its production licence earlier this year because of inadequate safety measures, according to state television.
More than 40 people helped with the rescue and recovery operation.
In 2010, more than 2,400 people died in coal mine accidents in China, according to official statistics, which is more than six workers each day.