The explosion happened at about 2 p.m. Saturday in the Taozigou coal mine in Sichuan province, China's Xinhua news agency reported. A total of 108 miners were in the mine at the time of the incident -- 28 died and 18 others were injured, officials said.
An initial investigation of the incident by the State Administration of Work Safety found that the explosion was a result of high gas density due to poor ventilation and that the Taozigou mine was not authorized to be in operation, said Fu Jianhua, deputy director of the agency.
SAWS ordered all coal mines in the area to suspend operations so the agency can carry out safety inspections, officials said. Any that fail to meet work safety conditions will be shut down.
Liu Jie, deputy governor of Sichuan, called for the Taozigou mine to be shut down "as soon as possible."
SAWS director Yang Dongliang said a more thorough investigation into the incident at the Taozigou mine is underway.