KUNMING, Oct. 9 (Xinhua) -- Four people died and one other was injured after a coal mine shaft collapsed on Thursday afternoon in southwest China's Yunnan Province.

The cave-in occurred at around 2:30 p.m. in the licensed Zhenxing mine in Laibing Town, Xuanwei City. Eight people were in the shaft at the time of the accident, according to the city government.

Rescuers pulled out the victims at 4 p.m.. Those that were seriously injured died in hospital despite doctors' efforts. A slightly-injured worker was continuing to receive medical treatment. The others were unharmed.

The cause of the cave-in was being investigated.