This brought the death toll from two coal mine accidents in Shanxi province in recent days to 81, a day after rescuers at another mine mishap said all 34 miners trapped after a fire on Sunday had died.
The Xinhua News Agency said rescue work at the Jiaojiazhai colliery in Xinzhou city where the Nov. 5 gas explosion occurred was hampered by the high levels of dense, toxic gas as well as several cave-ins.
There were 393 miners working in the pit when the blast went off, and 346 of them escaped.
Casualties have been mounting in the latest string of accidents to hit China's dangerous coal mining industry, which recently has increased production to feed a surge in demand for winter heating fuel.
Elsewhere, rescuers said eight miners had died in a coal mine flood Sunday in Guizhou province in the southwest, Xinhua reported.
The flood trapped 11 miners at the Debi colliery in the county of Libo, but three were rescued, Xinhua said.
Floodwater in the shaft measured 100 feet deep — and was at least 71,000 cubic feet in volume, the report said.
China's poorly regulated mining industry is the deadliest in the world, with about 6,000 people killed each year in explosions, floods, collapses or other disasters. Lax safety rules and poor safety procedures are often to blame.
The government has launched safety campaigns in recent years and says it has closed thousands of mines in an attempt to rein in the accidents, but death tolls remain high.