Load Transfer to Pillar System and Surrounding Walls in Enclosed Room-and-Pillar Mining Panels

ABSTRACT: This study investigates how pillar system geometry affects load distribution in room-and-pillar mining. Numerical analyses using FLAC3D adopted two approaches: one with variable panel width based on design parameters, and another with fixed panel width while varying pillar configurations. Under fixed-panel width conditions, two scenarios were examined: changing pillar count with fixed pillar width, and changing pillar width with fixed pillar count. The total pillar area was kept the same at each step from the both scenarios for consistent comparison. For conceptualization, the mining panel was regarded as divided into support-dependent area and wall-dependent area, then the load transfer ratio to the pillar system was analyzed for each case. Overall results show that load transfer to the pillar system decreases with fewer pillars, smaller total pillar area, higher opening width-to-pillar width ratio, and greater depth. Under equal total pillar area, multiple distributed smaller pillars carried more load than a single larger central pillar. These findings indicate that pillar design significantly influences load-sharing between pillars and abutments. The load transfer ratio can be adjusted through pillar system design, offering a means to improve both structural stability and resource recovery. This highlights the potential for optimizing pillar layouts to enhance mine performance.