Numerical study of 2D & 3D ERT with sensitivity analysis for subsidence in the coal mining area

Subsurface cavities are mainly responsible for ground subsidence in and around coal mines. There is need to use an advanced high-resolution three-dimensional (3D) Electrical Resistivity Tomography (ERT) technique to detect anomalies and map subsurface precisely. The present study demonstrated the numerical evaluation of 2D and 3D-ERT for air-filled and water-filled cavities. Models simulated with reasonable resistivity values for voids and formations by considering bord and pillar mining environments in multilayer earth. Wenner, Wenner-Schlumberger, and Dipole-dipole arrays incorporated with and without a barrier to getting the best possible output. We used the Res2dinv and Res3dinv programs for data processing. 3D Dipole-dipole inverted geo-electrical section better showed the subsurface cavities signature than the results obtained from other applied arrays. The sensitivity section corresponding to used electrode configurations gives a more detailed picture of the subsurface for better interpretation. The 3D volume of the subsurface overcomes the limitations of 2D ERT to detect cavities within the coal seam.