State news agency Xinhua cited Jiangxi’s coal mine safety supervision department as saying the miners were under the pit when the accident occurred in Shangrao county at around 10 p.m. (1400GMT) Friday.

A section of the shaft at the privately owned Yongji Coal Mine collapsed in the explosion.

Rescue efforts are underway.

According to Xinhua, police have captured the owner of the mine – whose safety production license is undergoing a renewal process — and placed him under investigation.

China — the world’s biggest consumer — produces more than one-third of annual global coal output but accounts for more than two-thirds of mining deaths around the world annually, Mining Technology reported last year.

In August, 13 people were confirmed dead after a gas explosion at a coal mine in southwestern Guizhou province where five others were injured and 56 rescued.

Last December, a gas explosion at a coal mine in northeastern Heilongjiang province left 10 miners dead, just weeks after fires at two mines left dozens of workers dead in Liaoning and southwestern Guizhou province in two days.

Lax regulation and poor operating procedures make China’s mines the deadliest in the world.