The miners were drilling in a coal mine in Fugu County, in Shaanxi Province, north-west China.
According to official Chinese news agency Xinhua, the accident at the Fuyu mine trapped nine miners who were working around the drilling passage.
Seven were rescued and a search is continuing for the missing men.
Fuyu Coal Mine is one of the 300 coal mines ordered to halt production for improvement of work safety in September, Xinhua reported.
It obtained a licence for work safety in October and resumed production after surviving an inspection this month.
Since the beginning of the year, more than 4000 Chinese workers have lost their lives in more than 2300 mining accidents.
