Four people were killed and one injured in a slope failure in a phosphate mine in southwest China's Guizhou province Saturday, local authorities said. The accident occurred at around 4 p.m. Saturday in an open-pit mine of Wengfu phosphate mine in the city of Fuquan, killing two people immediately and trapping three others, Xinhua quoted the municipal publicity officials as saying. The three were later pulled out, but two were already dead while one sustained injuries. An investigation into the cause of the incident is underway.