Mine Subsidence Predictions Using a Mechanistic Modelling Approach

A practical, predictive method, based on closed form solutions for displacement and strain around longwall panels, is proposed to facilitate the assessment of subsidence and changes to ground conditions above longwall mining. The displacement discontinuity method is employed to simulate the displacement and strain field around a single longwall panel in a three-dimensional transversely isotropic medium. The analytical solutions are effectively combined and implemented in MATLAB language, which allows for deriving key information to subsidence predictions. Predictive accuracy, applicability and efficiency of the code are demonstrated using data from collieries in New South Wales. Close agreement was achieved between the key parameters maximum tensile strain, maximum tilt, maximum convex and minimum concave curvature derived by empirical methods, the proposed displacement discontinuity method and survey records. However, there is still scope for improvements in this approach and additional testing is recommended in order to further validate the proposed method and evaluate its potential for practical longwall mining impact and risk assessments.