Three government officials would be sacked after 12 people died when a gas pocket ignited in a coal mine in north China's Shanxi Province, local authorities said Monday.

The accident occurred at 11:30 p.m. Sunday when 16 miners were working in a shaft in the Donggou Colliery Co., Ltd. in Jiexiu City, under the administration of Jinzhong City, said a spokesman with the Shanxi Provincial Work Safety Administration.

The Communist Party of China Jinzhong Municipal Committee has proposed to dismiss Han Haiyun, vice mayor who was in charge of coal mine safety;

Zhang Yiqian, head of the Jiexiu Municipal Administration of Coal Mine Safety; and Yang Guangdong, assistant mayor.

The proposals still need to be approved by the Jinzhong Municipal People's Congress.

The police have also detained five coal mine executives, including Xue Guohua, chairman of the Donggou Colliery Co., Ltd, Liang Yunqi, its general manager, and Liang Changfu, head of the mine.

The mine was expanding its annual production capacity from the authorized 300,000 tonnes. The workers violated a safety rule that prohibited the demolition of a wall between the shaft and a disused area of the mine where the gas was accumulated in high density, a spokesman said.

The four survivors were under observation in hospital. Doctors said they were stable.

The Jiexiu city government has launched safety inspections to prevent more accidents.