Optimized Analysis on Boundary Distance of Mine with Surface and Underground Combined Mining

Based on the practices of the surface and underground combined mining engineering in the thick and horizontal seam of Pingshuo Mining Area with a shallow mining depth as the background,the research method combined with the similar simulation test and the numerical simulation analysis was applied to establish three kind engineering geological models and numerical calculation model with the surface and underground combined mining mode.Based on the stability of the slope transportation bench for the surface and underground combined mining,the paper provide the max subsidence difference between the two ends of the transportation bench and the displacement curve in convergence or not as the basics.A comparison analysis was conducted on the sequences of the surface mining and the underground mining direction.In order to reduce the coal left in the slope,the mine boundary parameters of the surface and underground combined mining were optimized.