The state-owned  Chenjiashan Coalmine. (Photo: Xinhua)

A gas accident took place at the Chenjiashan Coalmine, a state-owned coal production base in northwest China's Shaanxi Province, around 7 a.m. on Sunday, but no other information is available such as the exact number of miners underground and casualties, if any.

By press time, no miners have been seen to emerge from the colliery, according to local sources.

Information from the provincial bureau of coalmine production safety said it was unknown whether there was a gas explosion or burning beneath the shaft.

The Chenjiashan Coalmine is administered by the Tongchuan Mining Administration of Shaanxi Province.

Cause of the accident is under investigation.