The blast in Jixi, a city in Heilongjiang province, happened at 5 a.m. when the miners were working underground, the official Xinhua News Agency said, citing work safety officials from Jixi. It said the mine had no operating license and that the owner fled after the accident.
Rescue efforts were continuing later Saturday.
China's poorly regulated mines are the world's deadliest despite repeated government pledges to boost safety. Many accidents are blamed on a lack of required fire and ventilation equipment or a disregard for safety rules.
Last year, more than 6,700 deaths were reported in explosions, cave-ins and other disasters. In the past month alone, 67 Chinese coal miners have been reported killed in fires and cave-ins.
In February, 37 miners were killed in a Jixi mine explosion. Last June, another explosion in Jixi killed 115 miners in what state media said was the fourth deadliest coal mine accident in China's history. Two more blasts there since November killed a total of 27 people.
