The official Xinhua News Agency said earlier that 96 miners remained trapped following pre-dawn blast at a mine belonging to the Shanxi Jiaomei Group in Gujiao city near Taiyuan, the capital of Shanxi province.
Xinhua also said earlier that 340 miners were rescued, of whom 24 were seriously injured.
It was not immediately clear whether the 44 fatalities were among those who were trapped in the mine or those who had been transported 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 Shanxi Jiaomei Group is China's largest producer of coking coal, and operates 28 mines.
Although China has worked to cut mine accidents by closing more than a 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.