3-D Numerical modeling and assessment of subsidence caused by underground copper ore mine

Surface subsidence resulting from underground mining presents a significant challenge in mining engineering, potentially damaging surface structures, environmental concerns, the safety of personnel, and causing substantial economic losses for the mine. This study aims to investigate and predict ground subsidence resulting from underground mining activities, focusing on a copper ore mine in India, adopting the blast-hole stopping technique. In this study, various subsidence prediction modeling techniques (empirical, influence function, and theoretical/numerical/analytical) have been outlined for assessing mining-induced subsidence. A three-dimensional (3-D) numerical model was developed using the Finite Element Method (FEM) code Strand7, encompassing geologic complexities such as joints and faults, connections between different lithologies, and the stoping sequence selected from the mine plans to investigate the mechanism of surface subsidence induced by underground mining. The model simulates various mining phases, including the virgin state, ongoing operations, and predictions for the subsequent five and ten years, to assess the related strain and displacement in all directions. To improve model precision, rock mass characteristics and in-situ stress conditions were optimised via backward modeling. The novelty of the work lies in the coupling of backward modeling for geotechnical parameter improvement within a three-dimensional FEM framework, applied to a real-world mining sequence in a complex geological setting. This method enhances the accuracy of predictions and provides a practical approach to subsidence prediction in operational mines. This research helps to promote safer mine planning and enables the construction of dependable, site-specific methods.