Abstract: To study the stability of strip mining coal pillar and influence to surface under the condition of different recovery coefficient，numerical simulation software FLAC^3D and Tecplot were adopted, vertical stress distribution of different mining and pillar width strip  coal pillar and maximum surface subsidence were studied. The results indicated: sustentive pressure of coal pillar per unit area presented linear increase with the increase of recovery coefficient; shape of stress isoline of stress concentration area at edge of coal pillar presented changes from saddle to platform shaped than arched, platform shaped could be judged as the mark and critical point from stability to instability of coal pillar; formula between maximum surface subsidence and strip mining stoping rate and formula between maximum vertical stress and recovery coefficient were established based on simulation calculation results, provided scientific basis for relative calculation in future.

Key words: Strip mining, FLAC^3D, Tecplot, Coal pillar stability