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Strip-pillar mining method is one of the most important technical measures to control mining subsidence, protect surface buildings (structures), improve ecological environment, and realize“green mining”of mining area in China. With the increase of coal mining depth, it is increasingly predominant to extract deep reserves under buildings. Deep strip-pillar mining is gradually applied in practice. In order to analyze proper mining depth of deep strip-pillar mining, based on the theory of Probability Integral Method, safety mining depth and limit mining depth of strip mining were calculated and analyzed, then the definition of deep strip mining and reasonable mining depth are discussed. Based on some field investigations, data collections and comprehensive analyses, the stress distribution laws of the surrounding rock, and the laws of overlying strata and surface movement ,were studied by using photoelastic experiment and FLAC3D numerical simulation, when the mining depth changes under the conditions of deep strip-pillar mining. Based on analyzing these geology and mining factors affecting mining subsidence and strip-pillar mining, and according to the specific geology and mining conditions of FengFeng WanNian coal mine, the numerical stimulation models of deep strip-pillar mining were set up by FLAC3D. The relationship between these subsidence factors, such as, Young’s modulus, the depth of alluvium, mining height, mining depth, sizes of working section, mining and pillar width and so on, and the laws of surface movement in deep strip-pillar mining was studied. Then the relationship between these subsidence factors and the laws of surface movement was obtained. Meanwhile, some main control factors affecting mining subsidence in deep strip-pillar mining was also obtained.
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