The blast occurred on Friday evening in the Dashan coal mine in Pingba county, provincial officials said.
An investigation has been launched into the incident, the Xinhua news agency reported.
China’s mines have a notoriously poor safety record, despite officials efforts to improve standards.
Last month a coal mine gas explosion in the north-eastern Jilin province killed 18 miners and injured 12 others.
More than 1,300 people were killed in mine accidents in 2012.
Deaths and injuries are often blamed on a failure to follow safety procedures.