GUIYANG - Seven people were dead and another two were injured in a coal mine gas blast in Southwest China's Guizhou province, local authorities said Friday.

The explosion happened around 6 am on Friday at Shibanpo Coal Mine in Jinsha county, Bijie city.

Thirty-one miners were working underground when the explosion occurred, and 24 of them have escaped from the mine shaft, and the two injured have been sent to hospital for treatment, the government of Xinsha said.

Preliminary investigation indicated that the cause of the gas explosive is because a sealed shaft was opened without permission.

Relevant departments, involving firefighters, public security and health personnel, have been mobilized to handle the accident.

With an annual output of 300,000 tonnes of coal mine, Shibanpo Mine is a private coal mine.