Abstract: Stability conditions around mined-out areas that exist in an underground mine have a great influence on the safety, production and economic performance of the mine. The effect of mined-out areas and a natural cavity on the deformation, stress, failure zone and stability around the mined-out areas and the cavity located in a metal mine mass at the three-dimensional (3D) level were studied. The information available on stratigraphy, geological structures, mined-out areas, a natural cavity, in-situ stress measurements and geo-mechanical properties of intact rock and discontinuity interfaces have been used to build a 3D numerical model using 3DEC. The stress and deformation conditions around the mined-out areas and the cavity in the metal mine rock mass were simulated. Finite size discontinuities and fairly complex 3D geology have been simulated. 3D stress analyses have been conducted under several possible material property values to study the effect of material properties on the deformation, failure zones and stability. The results show the areas which can have tensile or shear failures and also high deformations. On the basis of measured with the AGI, 3DEC numerical simulation is used, by the comparison predicting the results with the actual settlement conditions, applicability of 3DEC system in the mining subsidence prediction has been verification, it proves that mining subsidence can be better reflected the actual situation.

Key words: AGI, 3DEC, High-density electrical method, Underground mined-out areas, Stability analysis