Fracture development and permeability evolution of overburden rocks containing faults.

This article focuses on the evolution and characteristics of mining-induced overburden fractures in fault-affected zones, specifically analyzing the East 301 working face of the Dashuitou Coal Mine. Using numerical simulations with the Universal Distinct Element Code (UDEC) and field observations, the study examines how varying fault dip angles influence fracture frequency, angle, opening, connectivity, and fractal dimension, which in turn affect gas migration pathways and extraction efficiency. The research proposes a fracture permeability-based gas zoning method, validated by borehole visualization and directional gas extraction experiments, demonstrating enhanced gas extraction rates—up to 15.6 m³/min—in fault-affected areas. These findings provide a scientific basis for optimizing borehole layouts and gas control strategies to improve safety and efficiency in mining operations within complex geological settings.