Applying noncantilevered support of mechanized complexes for developing flat seams

Purpose. Substantiation of applying additional load-bearing structure of powered support near the face onto the bench formed within the seam by the cutter-loader actuating element, which allows to increase efficiency of coal winning. Methods. Underground investigations of bearing capability and the character of bend fracture in terms of eight coal seams in Western Donbas mines are performed. Relationships between coal bench bearing capability of flat thin seams and the place of setting load-bearing support are determined by analytical method. Correlation dependence between bench strength and coal hardness within the sample is established. Findings. The study has shown that coal bearing capability within the bench is basically determined by coal hardness, thick-ness and location of the friable band, the area and location of the spinning unit. Dependences between bearing capability of coal bench and the distance from axle mounting of the spinning unit die to the bench edge are deter-mined. It is shown that the strength limit of coal bench is directly proportional to the strength limit of coal hardness within the sample and inversely proportional to the distance from the place of load application to the face. This study enables to determine the location of supporting structure depending on the coal hardness within the samples. Advance cut under the seam roof reduces the resistance to coal bench cuttability and induces bench spalling into large fragments. Installation of noncantilevered support structures onto coal benches decreases the rate of vertical displacement of benches and roof blocks above. Originality. When applying complexes with powered support mechanisms extensible to the whole thickness of the seam under extraction, additional load-bearing support can be installed directly on the spalling bench near the face. It will pre-vent caving and reduce coal ash content. Practical implications. This study has shown that the application field of noncantilevered support with the canopy resting on coal benches can be chosen according to the results of the coal sample strength testing, as the mine research into coal bench bearing capability is too labour-intensive. The performance of advanced cutting under the seam roof will enable to re-duce power consumption of mining and output of coal fine fraction. Installation of load-bearing structures of non-cantilevered supports onto the coal bench allows to prevent caving and reduce coal ash content.