Vertical shaft collapse at the Jinchuan Nickel Mine, Gansu Province, China analysis of contributing factors and causal mechanisms

In mining areas, vertical ventilating shafts are often threatened by ground movements induced by underground mining. In this paper, damage characteristics related to collapse of the vertical ventilating shaft at the No. 14 exploratory line in Jinchuan Nickel Mine, China are documented. The damage mechanism is then analyzed based on comprehensive consideration of geological conditions and distribution of underground excavations. The results indicate that the high dip angle of the ore body and fault/fissures were responsible for the damage of the shaft when ground movements occurred. Although the damaged shaft was repaired in a short time, its stability and safe usage are still threatened by potential future ground movements, because the shaft is located within a subsiding depression induced by underground mining. This case study indicates that when designing an underground mining operation, it is very important to locate a shaft outside of any area where future mining-induced subsidence may occur.