Indicators sensitivity analysis for environmental engineering geological patterns caused by underground coal mining with integrating variable weight theory and improved matter-element extension model.

This research utilized the variable weight theory (VWT) and improved the matter-element extension model (MEEM) to conduct an indicators sensitivity analysis of environmental engineering geological patterns (EEGPs) related to underground coal mining. First, four types of EEGPs, i.e., basically unaffected model, gradually restored model after destruction, gradually deteriorated model and disaster model, were defined. Subsequently, 13 indicators were selected from different spheres. Then, a sensitivity analysis for EEGPs was conducted by VWT and improved MEEM. On the basis of changes in indicator values by ±10-50%, indicators sensitivity was separately determined in four types of EEGPs. In conclusion, rainfall capacity, evaporation capacity and normalized difference vegetation index (NDVI) are sensitive indicators in a basically unaffected model, while the thicknesses of the coal seam and laterite are sensitive indicators in the other three EEGPs. For comparison, types of EEGPs were tested by both VWT and traditional MEEM, verifying the accuracy of indicators sensitivity results and reasonability by VWT and improved MEEM method. Finally, mining measures such as layered, stripe, filling mining and grouting reinforce method corresponding to thicknesses of coal seam and laterite were proposed. Therefore, specific mining methods under types of EEGPs can be provided to decision-makers in the mining industry and to environmental protection departments.