Abstract:To investigate the stability of the upward horizontal layered filling method in the eastern mining zone at the 3972 m level of the Hongniu Copper Mine, the study first determined the critical stope span using the Mathews graphical method, based on the stope structural parameters and mining sequence. Subsequently, a numerical model of the upward horizontal layered filling method was established to conduct a numerical simulation study on stope stability during the extraction process. The results indicate that under the critical span condition, the roof subsidence of the access drift is 4.8 mm, the floor uplift displacement is 6.6 mm, and the plastic zones did not interconnect, confirming that the stope remains stable. This research provides a scientific basis for safe extraction in the mining zone, ensuring safe mining operations. It offers reference value for stope method selection and stability analysis in similar mining conditions.