Iran Press/Asia: Rescuers were dispatched to the Diaoshuidong mine in Chongqing, a huge metropolis around 1,800km west of Shanghai, and investigators were working to determine.
The report said the accident happened at around 5:00 pm local time (0900 GMT) without giving further details.
An earlier accident at the mine claimed the lives of three people in 2013, AFP reported.
Deadly mining accidents are common in China, where the industry has a poor safety record despite efforts to improve coal production conditions and the crackdown on illegal mines.
In December 2018, seven miners were killed and three others injured in an accident at a coal mine in China's southwest.
In October 2019, also 21 miners died in eastern Shandong province after pressure inside a mine caused rocks to fracture and break, blocking the tunnel and trapping workers. Only one miner was rescued alive.
According to China's National Coal Mine Safety Administration, the country saw 375 coal mining-related deaths in 2017, down 28.7 percent year-on-year.
Read more:
Death toll in China coal mine roof collapse rises to 21
