Existing coal filling mining technologies face significant challenges of controlled surface subsidence, efficient utilization of waste rock in coal mines, and a shortage of adequate filling materials. This study introduces an innovative cut-and-fill mining method designed to strategically partition the goaf into cutting and filling zones. In the cutting zone, in situ filling materials are employed to construct waste rock column supports adjacent to the filling zone, thereby achieving controlled surface subsidence. This approach is integrated with long-wall mining operations and implemented using advanced, comprehensive equipment. FLAC3D simulations were conducted to investigate the patterns of stress distribution, surface deformation, and plastic zone formation within the mining field. With the implementation of the cut-and-fill mining balance, key observations include a reduction in maximum principal stress near the center of the goaf, an increasing trend in minimum principal stress, regular displacement distributions, and intact plastic zones positioned vertically away from the stope and horizontally close to the center of the stope. Compared to traditional caving methods, the cut-and-fill technique significantly reduces maximum vertical displacement, by nearly 95%, and maximum horizontal displacement, by approximately 90%. Additionally, it minimizes energy accumulation, lowers overall energy release, and prolongs the release period. Importantly, this method facilitates the resourceful utilization of approximately 800 million tons of waste rock, potentially leading to an estimated reduction of 500 million tons in CO₂ emissions. By achieving a balance of three effects—harmonizing coal extraction and filling capacity, aligning the supply and demand of filling materials, and optimizing the balance between filling costs and mining benefits—this method provides a sustainable and eco-friendly solution for the coal mining industry. The findings of this study are crucial for guiding the industry towards more environmentally responsible practices.

To address the limitations of existing subsidence control technologies in coal mining, this study systematically investigates the fundamental principles of cut-and-fill mining, the stability mechanism of the filling body, and the influence law of key parameters on mining engineering effects, through a comprehensive research framework integrating theoretical analysis, similar material simulation and numerical simulation. Firstly, the mechanical characteristics of horizontal and diagonal shear failure of gangue pillars are revealed via theoretical derivation. It is clarified that the diagonal stability of the gangue pillar can be guaranteed when its aspect ratio is ≤0.5, and the lateral constraint of metal mesh can effectively enhance its horizontal stability. Secondly, based on a physical model with a size similarity ratio of 1:100, the overburden failure characteristics are obtained: only local cracks appear in the immediate roof and the basic roof presents gentle subsidence after cut-and-fill mining, which directly verifies the effective control effect of this technology on mining-induced overburden movement and surface subsidence. On this basis, multiple sets of orthogonal tests are designed using FLAC3D software (5.0) to analyze the effects of roof cutting width, filling width and coal seam thickness on roof displacement and filling area stress. Combined with grey correlation analysis, it is determined that coal seam thickness is the most critical factor affecting the mining effect, with the correlation coefficients for roof displacement and filling area stress reaching 0.79 and 0.93, respectively. The research shows that the parameter combination of 10 m roof cutting width + 10 m filling width (Group 10-10-X) can achieve the optimal balance between subsidence control efficiency and filling engineering benefit; for working faces with higher requirements for surface subsidence control, the combination of 5 m roof cutting width + 10 m filling width is recommended. The research results clarify the action mechanism of cut-and-fill mining, optimize the key engineering parameters, and provide a solid theoretical basis and technical support for the engineering popularization of this technology and high-precision surface subsidence control.

Traditional underground backfill mining generally faces persistent bottlenecks such as insufficient filling material supply, high transportation costs and low filling efficiency. As an emerging green mining technology realizing in situ backfill material self-sufficiency, cut-and-fill mining provides an effective solution to the above problems, but the influence mechanism of its key geometric parameters on engineering performance remains unclear, restricting standardized parameter design and field promotion. Taking a shallow-buried coal mine in Ordos as the engineering background, this study carries out physical similarity simulation tests to systematically investigate the evolution laws of overburden displacement and stress distribution under three controlled scenarios: a baseline condition (4 m mining thickness, 10 m filling width), reduced mining thickness (2 m, 10 m), and increased filling width (2 m, 15 m). The results show that mining thickness acts as the dominant factor governing the strata control effect: when mining thickness is reduced from 4 m to 2 m, the maximum vertical displacement at the 10 m survey line decreases by 53.8%, the coal pillar stress concentration factor drops significantly, and the main roof maintains structural integrity without large-scale fracture. Increasing filling width enhances the bearing capacity of gangue pillars and restores filling zone stress closer to the in situ level, but tends to induce separation fractures in higher strata. Overall, the strata behavior of cut-and-fill mining presents distinct zoning characteristics, with high-position strata movement transitioning to coordinated integral deformation instead of severe separation and fracture. The findings provide an experimental basis and design reference for geometric-parameter optimization and engineering application of gangue backfill materials in underground mining.