Different methods of longwall full mining partial filling and optimal design of filling process

Different methods of longwall full mining partial filling have been extensively studied to meet the special mining requirements of pressure coal resources and residual coal resources. The research aims to reduce production costs, ensure safe and efficient production of filling mining. Three longwall partial filling mining technologies are proposed: room-pillar filling mining, parallel strip filling mining, and vertical strip filling mining. Numerical simulation and the Analytic Hierarchy Process (AHP) model are utilized to analyze the effects of these methods. The results demonstrate that vertical strip filling mining exhibits the smallest surface deformation and the most regular displacement distribution. Additionally, an AHP model is employed to determine the index weights for safety, economic factors, stress, displacement, and filling cost. A hierarchical structure is established with safety and economic mining as the target layer, and stress, displacement, and economic factors as the criterion layer. The vertical strip filling mining method was calculated as the comprehensive optimal scheme. In practical operations, the filling technology and filling material performance play crucial roles in determining the filling effect. The study includes the optimization analysis of the filling technology, focusing on the composition of the coal gangue paste filling system and the optimization of the system components. Additionally, the study investigates the optimization analysis of filling materials, particularly the performance optimization methods. Experimental results demonstrate that optimizing the filling materials can improve the performance of the filling paste, enhancing both early-stage and long-term compressive strength. This research can provide valuable insights into the optimal design of longwall partial filling mining methods.