Analysis and forecast of influential factors of gas content in deep coal seam on the basis of the grey entropy

In order to improve the forecast precision of gas content in deep coal seam, taking deep coal seam No.11-2 in Pansan coal mine as example, grey entropy is proposed to research influencing factors of gas content. The GM(1,3), GM(1,4) and GM(1,5) gas content forecasting models are established to select an appropriate model with the highest forecasting precision according to the size of different influencing factors of grey entropy relation degree. The results show that the influencing factors of gas content in deep coal seam No.11-2 are in decreasing order the main fault distance, the buried depth of coal seam, coal seam thickness, the ratio of the sandstone and mudstone in coal seam roof and dip. The forecast precision of GM models is higher than the qualified level. What's more, the precision of GM(1,4) model reaches the first grade and average relative error is 5.0636%. In conclusion, GM(1,4) model can be adopted to accurately forecast gas content in deep coal seam No.11-2, which provides reliable references for safe and high-efficiency coal mining.