AN ANALYSIS OF THE FAILURE OF THE COMPOSITELY STRUCTURED OVERBURDEN WITH RED STRATA AND COAL BEDS AND ITS APPLICATION

The overburden in the mining influencing zone is often composed of red strata and coal beds in many coalmines. This paper evaluated the failure of the overburden and the establishment of safety pillars under water body for the coal seam No.3 of Permian System in the Taiping coal mine, Shandong Province. By evaluating hydrogeological condition of the Quaternary sediments and engineering geological characteristics of the compositely structured overburden with red strata and coal beds, its failure conditions during coal mining were characterized. As a result, the height of safety pillars was determined, which has been confirmed by the field tests and assured that no water-intrusion hazard or sand rush would occur.