Web pillar stability in open-pit highwall mining

Abstract When highwall mining technology is applied to recover large amounts of residual coal left under the a big open-pit mine, reasonable pillar width required ensure stability web pillars. Using numerical simulations, this paper studied characteristics abutment stress distribution in pillars different slope angles and depths, established relation describing pillar. The relationship between ultimate strength widths was also analyzed. In combination with failure yield zone, used explore instability mechanism Finally, optimal retaining were determined. Based on modeling results, mechanical bearing model cusp catastrophe pillar-overburden constructed. Additionally, criterion derived. By analyzing pillars, formula for calculating zone either side established. mining, can be deduced theoretically, providing significant guidance application technology.