The blast occurred at 1:49pm at the Wangfenggang Coal Mine in Huainan, which was under construction at the time of explosion, official news agency Xinhua reported.
Two of the dead were gas density inspectors and the other 10 were part of the construction team building the mine.
More than 5000 workers lose their lives in mining accidents annually. Between January and September 2005, according to Chinese officials, 4228 workers were killed in 2337 mining accidents.