Research and Application of Backfilling Process for Ensuring Safe Mining Face Passage Through Crossing Abandoned Roadways

In order to ensure the smooth and safe advancement of mining faces through abandoned roadways (ARs), this study investigates the backfilling process in a mining operation in western China, where abandoned roadways continuously appear ahead of newly arranged mining faces. A theoretical analysis of the immediate roof of the roadway is conducted, leading to the conclusion that the optimal spacing between backfilling bodies is 8 m. Numerical simulation software is used to examine the effects of different backfilling body lengths—6 m, 8 m, and 10 m—on the stress state, deformation characteristics, and stress distribution of the surrounding rock during mining. Based on the simulation results, appropriate backfilling body lengths are selected: 8 m for ARs perpendicular to the mining face and 10 m for ARs parallel to the mining face. The proposed backfilling process is validated through industrial tests, demonstrating its effectiveness in ensuring mining safety and improving economic efficiency.