Numerical Simulation of Surface Deformation Due to Caving in an Iron Mine

This paper presents a case study and discussion concerning land surface deformation induced by underground mining in an iron ore mine. The ore excavation was from mining depths of -360 m to -850 m in the western region of Chengchao iron mine. The ground deformations were studied by numerical modeling in FLAC software. Back-analysis of measured surface subsidence was used to calibrate the mechanical parameters of the rock mass used in the numerical model. Then, the rock movement and failure state were analyzed for different mining depths. The displacement angle and the caved angle of the rock were predicted, and predictions were made of the expected degree of damage to nearby surface facilities. The modeling shows that significant damage caused by underground mining should occur to buildings around the western ventilation shaft No.1 and the service shaft. Only minor damage is expected around the new auxiliary shaft and the skip shaft. No damage is expected near the western ventilation shaft No.2.