Taiyuan -- The death toll from a colliery blast in north China last week has soared to 35 while 12 people remain missing, rescuers confirmed on Monday.

Search and rescue teams found 12 bodies early on Monday in the Jiaojiazhai Colliery in Xinzhou, a city in the central northern area of Shanxi Province, where a gas explosion occurred at 11:45 am on November 5.

The death toll stood at 23 on Sunday.

Altogether 393 miners were working in the pit when the blast occurred, of whom 346 escaped.

Search and rescue efforts are continuing though rescuers believe the remaining 12 miners have little chance of survival, given the high intensity of toxic gas and serious cave-ins following the blast.

Families of the dead will each receive 200,000 yuan (US$25,000) in compensation. Seven families have been compensated so far.

Jiaojiazhai Colliery is owned by Xuangang Coal and Electricity Company under the Datong Coal Mine Group.

The State Council, the cabinet, set up an investigation team on Friday to investigate the tragedy.

Though the direct cause is still under investigation, the central government task force said it probably stemmed from ignorance of workplace safety and poor management.

Li Yizhong, head of the State Administration of Work Safety who is heading the task force, said he was "shocked to see long-existing and serious hidden dangers in the mine and how poorly informed the miners were".

Li vowed to severely punish the individuals and company responsible for the accident, and urged all coal mine owners in the country to learn a lesson.

Analysts said the accident was a warning of a possible surge of coal mine disasters as the demand for black coal rises in winter.

In October, the number of coal mine accidents surged by 26.1 percent over September. The number of miners killed rose by 44.4 percent.

The "infinite greed" of some mine owners, driven by the growing demand of the winter coal market, was the ultimate cause of the disasters, said Wu Jianming, professor with Taiyuan University of Science and Technologies.

"Winter is hell for miners. Some of the small, hazardous mines that have been closed will probably resume production in the winter regardless of the threat to life," said Wu, who also works for the State Administration of Work Safety as a consultant.