Rescuers said the death toll had risen to 44 by 11 a.m. local time, Xinhua said in a brief dispatch without providing details. State television channel CCTV reported that 21 workers remained trapped.
Earlier reports said 340 miners had escaped but 96 were trapped underground. Those reports said 11 miners had died after being taken to hospitals.
An official with the provincial government duty office confirmed the accident, but did not have any details. He would give only his surname Chen.
The mine is owned by Shanxi Jiaomei Group, China's largest producer of coking coal and an operator of 28 mines.
Although China has worked to cut mine accidents by closing more than 1,000 small, dangerous mines last year, the country's mining industry is still the world's deadliest. About 3,200 miners died in accidents last year, a 15 percent improvement over the previous year.
Many of the smaller mines have lax safety measures, and are plagued by fires, explosions, floods and other accidents.
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