A predictive methodology for multi-seam mining induced subsidence

Multi-seam longwall mining-induced subsidence profiles are often different from those of single-seam mining. As a result, conventional subsidence prediction methods are less reliable for multi-seam subsidence predictions. In this study, significant differences between the single and multi-seam subsidence parameters are studied in a multi-seam case study in Australia. Results from this case study are employed to establish a characterisation of the multi-seam subsidence, which is applicable for every multi-seam mining configuration. The proposed characterisation is then utilised for modification of a conventional Influence Function Method (IFM). In the modified method, namely Discrete-IFM, a mine section is divided into discrete segments with certain subsidence parameters. The resultant subsidence of each segment is calculated and then superimposed to achieve the final subsidence profile. Application of the Discrete-IFM is demonstrated in an example case study, where reliable subsidence predictions are achieved. It is illustrated that the Discrete-IFM offers a flexible approach for consideration of multiple subsidence parameters for different segments, which enables this method to predict irregular subsidence profiles.