Abstract: In order to determine the reasonable parameters of section coal pillar in Nan Liang coal mine. Based on the theories of coal pillar, the in-situ pillar stress observation and numerical simulation are used to study the project. Field observations show that the pillar load increases gradually as the distance of mining face gets near, it increases rapidly at the distance about 10 m, stress is larger at 4 to 6 m deep away from the roadway surface. Existing 20 m section coal pillar changes not obvious during mining, the coal pillar has not reached its failure strength, the size of coal pillar has the potential to reduce. The numerical simulation show that while 14 m section coal pillar keeps stability under the condition of coal seam buried depth of 135 m, the 13m section coal pillar is easy to lose stability, pillar stress increases the fastest in the working face location and stress is basically stable to the rear of the working face 30 m. The 14m section coal pillar is optimized and has achieved good application effect.

Key words: Nanliang coal mine, section coal pillar, coal pillar stability, pillar strength, reasonable parameters