The influence of an abandoned goaf on surface subsidence in an adjacent working coal face: a prediction method

Historical global coal resource exploitation has resulted in goaf abandonment at most mines, which, during the life of the mine, exerts a strong influence on the ability to exploit new working faces adjacent to any abandoned goaf. Thus, the distribution law of the surface subsidence basin above the new working face differs from the general law. Given the lack of research on this distribution law, this study uses a similar material simulation method to examine the influencing mechanism(s) of abandoned goafs on the subsidence basin in the same coal seam. Synthetic aperture radar (SAR) monitoring results of the 9310 working face in the Nan Tun coal mine, Yanzhou, China, are used to verify analytical results, followed by numerical simulation to study the influence of the abandoned goaf on the subsidence basin. Finally, to accurately predict surface subsidence influenced by the abandoned goaf, inflection point deviations are selected and discussed in terms of the probability integral method. This allows for prediction of the distribution of the surface subsidence basin, and moreover, the predicted results are found to be consistent with the SAR monitoring results when the derivation of inflection points is revised.