The blast ripped through the mine in Shaodong county in south China's Hunan province, Xinhua reported.
Investigators at the scene reported that damaged ventilation shafts and illegal electrical systems were believed to be the cause of the accident.
The mine had been ordered to stop production last August, and lacked an operating licence and safety permit, Xinhua reported.
The Chinese coal industry is currently implementing plans to shut down the thousands of small, inefficient and dangerous coal mines that flout safety regulations and operate illegally.
