Rescuers found bodies of the nine people at 11 p.m. following a nearly 50-hour rescue operation, the Panzhou city government said.
The coal and gas explosion occurred around 9:10 p.m. Monday in Zimujia coal mine in Panzhou City, killing four people and leaving nine others missing.
A further investigation into the cause of the accident is under way.
The mine belongs to Zhongrong International Trust Co. Ltd., with a designed production capacity of 300,000 tonnes a year. Its safety license expires in September 2019.