Construction and application of feasibility evaluation model for gas extraction in goafs of abandoned coal mines

Against the background of carbon neutrality and carbon peaking policy, the development of gas resources in abandoned coal mines can generate high resource, economic and environmental benefits. The evaluation index system is established through field research and literature review from technical feasibility and economic rationality aspects. The game theory-fuzzy comprehensive evaluation model is established by combining the weighting method of game theory with the fuzzy comprehensive evaluation method. The abandoned Gushuyuan Mine is used as an example to verify the rationality of the evaluation model. The weights of gas resource conditions and gas preservation conditions in the first-level indicators are as high as 0.4391 and 0.3836, indicating that coal mine gas storage and air tightness are the decisive factors influencing the feasibility of gas drainage in the goaf of abandoned coal mines. Among the secondary indicators, the weights of methane concentration of the ground borehole and the water inflow of the mine are as high as 0.091 and 0.087, indicating that the gas purity and the severity of water damage in the gas-rich areas of the abandoned coal mine goaf are the key factors affecting the feasibility of gas drainage. The established evaluation model corrects the weight distortion caused by the single weighting evaluation method, and it has the advantages of subjective and objective weight determination methods. The rationality of the game theory-fuzzy comprehensive evaluation model is proved.