Abstract:
As shallow mineral resources become increasingly depleted, many gold mining companies in China have begun recovering remnant ore from shallow, high-grade ore bodies. During this process, stope stability and surface subsidence are critical indicators in safety assessments, making it necessary to investigate how ground stress evolves during mining operations. This study was based on a pillar recovery project in shallow stopes at a gold mine in Liaoning Province. The top-pillar recovery process was simulated using FLAC
3D, and ground stress was monitored in key areas during recovery. The results reveal how ground stress evolves in the rock surrounding the stope during top pillar recovery. The numerical simulation results indicate that top-pillar recovery increases the displacement of the surrounding rock by 0.3−0.5 cm, concentrates ground stress around the stope, increases tensile stress by 0.2−0.4 MPa, and expands the plastic zone, with the failure mode shifting from shear to tensile failure. Ground pressure monitoring data show that the stress in the surrounding rock increases by 0.2−0.6 MPa after the disturbance caused by top pillar extraction, which is consistent with the simulation results and validates the reliability of the numerical simulation. Given that the ground pressure adjustment is small and eventually stabilizes, its effect on overall stability is limited, indicating that the gold mine remains stable during remnant ore recovery. The results show that combining ground pressure monitoring with numerical analysis during pillar recovery enables an accurate assessment of the stability of the rock surrounding the stope and provides theoretical guidance and safety assurance for on-site operations.