Coal and gas outburst risk assessment based on combined weighting and extended matter-element theory

Coal and gas outburst risk assessment is critical for deep mining safety. This study proposes a novel approach integrating an improved analytic hierarchy process (IAHP) and entropy weight method (EWM) with extended matter-element theory to address these limitations. A three-level evaluation system was established, incorporating coal seam characteristics, gas parameters, and geological structures as key indicators. Subjective weights derived from expert judgments (IAHP) and objective weights based on data entropy (EWM) were combined using averaging theory, enabling a hybrid weighting framework. The extended matter-element model further facilitated dynamic coupling analysis of multi-indicator interactions, enhancing risk assessment precision. A case study at a Chinese mine's 81203 working face demonstrated the model's effectiveness: the evaluated risk level (Grade II, weak hazard) aligned with field data. The rationality of the model was validated. In conjunction with the original data of each parameter and the evaluation indicators, a thorough analysis of the causes of gas outburst in the 81203 working face was conducted. The evaluation results guide safe production in the subsequent stage of this working face.