Aerial photo shows the site of a rock burst accident in Yuncheng County, east China's Shandong Province, Oct. 27, 2018. As two more miners were confirmed dead, the death toll rose to 13. Another eight miners remain trapped. The accident occurred at Longyun Coal Mining Co. Ltd. in Yuncheng County on Oct. 20. (Xinhua/Guo Xulei)

JINAN, Oct. 28 (Xinhua) -- As two more miners were confirmed dead, the death toll rose to 13 after a rock burst at a coal mine in east China's Shandong Province, local authorities said Sunday.

Another eight miners remain trapped in a 74-meter-deep tunnel, which is blocked by a falling coal seam at both ends, according to the emergency rescue headquarters.

Rescuers have cleared 42 meters of the tunnel as of 6 a.m. Sunday and are working on the remaining 32 meters from both ends.

The accident occurred at Longyun Coal Mining Co. Ltd. in Yuncheng County on Oct. 20. A total of 22 people were trapped in the tunnel after coal fell at both ends from the rock burst. One has been rescued.

Rock burst accidents are often caused by fractures in rocks due to mining.