INFLUENCE OF THE MULTI-LEVEL MINING ON THE GROUND MOVEMENT IN THE JINCHUAN NO.2 MINE

Multi-level mining in the Jinchuan No.2mine had attracted extensive research interests. In particular,rock mass deformation and catastrophe was the most prominent one. In this study,surface monitoring results proved that no evident mutation or abnormal events occurred from the beginning to end of the underground mining in the levels 1250 and 1150m. In addition,displacement boundary conditions should be adopted in excavation mechanical model rather than the force boundary conditions because the strain energy is a constant and the excavation activities should be considered as an energy transfer and dissipation process in the model. The small scale mining and filling techniques are helpful to avoid large magnitude rock mass movement,thus,the surrounding rock mass did not occur catastrophic instability but exhibit loose and break features in the mining. Finally,it indicated that the displacement rates of the ground rock mass are mainly associated with the mining rate and filling quality. Thus,the catastrophe phenomenon of ground rock mass movement and deformation will not happen if these two factors remain the same in the future.