Shaft deformation and failure due to rock mass movement induced by underground backfill mining of a metal mine

The vertical shaft plays an important role in underground tunnel mining mines. However, few attempts have been done on the deformation and failure mechanics of shafts suffering from rock mass movement in metallic mines undergoing mining activities. Numerical simulation methods and geomechanical methods are applied in the study of deformation, failure and stability of the line No. 14 ventilating shaft in Jinchuan No. 2 Mine under the conditions of different kinds of mining design. The results show that the shaft is seated in the scope of the depression induced by the underground mining, and the displacement of rock mass keeps increasing. Therefore the underground mining is the main factor for the safety and stability of the shaft. Moreover, whether mining of the rich ore body or combined mining of the rich ore body and lean ore body, the distribution regularities of displacement and stress of the shaft are similar, and the section of the faults is still the vulnerable zone of the shaft in which it influences the size and distribution of the displacement and stress greatly. Consequently, it is the faults which cross the shaft and lead to reactivation due to underground mining are the trigger factor, and the rock mass movement, rupture and fall are the primary form of the shaft deformation and failure mechanism, and this kind of fault effects will be aroused again in the future under the present circumstances of mining.