Seven coal miners have died and 17 are trapped after a shaft flooded at a mine in northern China.

State radio said on its website that more than 600 rescue workers were pumping water Tuesday and drilling holes from the surface in hopes of reaching those still inside the Jiangjiawan mine near the city of Datong. It said the bodies of those who died were retrieved Monday evening.

A total of 247 miners were underground when water rushed into the shaft Sunday evening. Of those, 223 people made it safely to the surface. Such accidents are usually caused by breaches of abandoned shafts where water has collected over time.

China's notoriously dangerous mines have seen declining deaths in recent years because of safety improvements and a decreasing demand for coal.