The first, which occurred about 5pm local time Sunday, was in the Hunan Province at the Gaoping Mine of Xiangmei Township in Yongxing County, Hunan Province. The other occurred about 4.30am local time Monday at Rongsheng Mine located in the Otog Banner area of Erdos City, Inner Mongolia Autonomous Region, the State of Work Safety told the Chinese media.

Eleven of the confirmed dead were working in the Rongsheng operation; a total of 34 miners were in the area at the time, according to Xinhua. While teams were able to rescue 12 of them, a search continues for five more. Several were taken to a local hospital for burn wounds.

A “technical upgrade” was underway at the 30,000-tonne capacity mine at the time of the accident, the government agency told reporters.

The Hunan mine, which was locally owned, was recently forced to turn over its production permit due to inadequate safety measures, the news service said. Those killed include the operation’s chief and deputy chief, a safety inspector for the owner, a gas inspector and seven miners.

Rescue crews could not enter the latter operation as of Monday evening local time, according to Sapa-AP, due to unsafe gas levels.

While reports from the country’s government have estimated 6000 lives lost in 2005, Chinese labour groups told the news service that total may be as high as 20,000.