Abstract：The section coal pillar has an important influence on the stability of the coal pillar and roadway, and the coal recovery rate. In order to determine the reasonable section coal pillar size of the No.3 coal seam of Wangpo Coal Industry, No. 3209 Face was taken as an example. The sound wave detection method was used to measure the development law of the roadway loose circle, FLAC3D simulation software was used to determine the most reasonable coal pillar width, and the engineering application test verified the effect of coal pillar width optimization. The results showed that under the condition that the width of section coal pillar was 19 ~ 20 m, the surrounding rock of roadway was class II stable surrounding rock, and the most reasonable width of section coal pillar was 10 m. The 3209 auxiliary transport crossheading adopted 10 m roadway protection coal pillar. Under the influence of roadway excavation, primary mining and secondary mining, the surrounding rock of roadway was stable, and good application effect and economic benefit were obtained.
