Experimental study and application of a new pillarless mining method with automatically formed roadway

The traditional reserved pillar mining (RPM) method suffers from significant resource wastage, stress concentration in coal pillars, surface damage, and other issues. To address these problems, a new pillarless mining method with automatically formed roadway (PMAFR) was proposed. This method was explored within the context of the Zhujiamao mine. Firstly, the roadway protection mechanism of the PMAFR method was investigated through physical model test. The results indicate that this technique separates the roof through directional cutting and utilizes the expansion characteristics of gangue to backfill the mining area, thereby supporting the roof. The roadway is protected through the combined action of roof cutting and backfilling. Subsequently, numerical simulations were carried out to validate the model test results. Finally, field engineering application demonstrated that the convergence of the retained roadway remained limited, meeting safety production requirements. The PMAFR method maximizes the reduction of roadway excavation, decreases resource waste associated with coal pillars, and achieves safe, efficient, and environmentally sustainable mining. • The protective mechanism of the PMAFR method was mutually verified through physical model tests and numerical simulations. • Fractal dimension was used to quantitatively characterize the fractal characteristics of overburden rock fractures under the PMAFR method. • During field application, the convergence of the roadway remained limited, meeting safe production requirements.