The key problem of the underground mining is to ensure opening strength of inclosing rock mass when conducting second and first working operations. Identification of the regularities of crack formation in the marginal rock mass is required for the integrated substantiation of geotechnological solutions ensuring opening strength of mine workings and maintaining them in working and safe condition. The type of lining, the technology of its construction predetermine the speed of workings development, advance and quality of the second working. Stress concentrations in the massif effect on its strength. Equation of the state of solid body under load considering the structure and defects in it plays the significant role in strength assessment. Substantiation of the workings strength is based on the assessments of maximum principal and minimum efficient stresses, taking into account fracturing of the millimeter range at the transition from samples that simulate the materials of full-scale samples, to rock masses. The method of the excavation workings security in order to reuse them with mobile cutting-off support of high rigidity installed in the temporary support pressure zone, and intensive displacement of the coal seam roof implements the principles of resource-saving, waste-free fastening technology. This method increases labor productivity, reduces the cost of excavation workings construction and the cost of mining of the ton of coal, ensures safety of mining operations. Improvement of mining technology is topical based on the expansion of the field of application of the efficient options for horizontal and panel mine development, pillar development system, including direct-flow ventilation schemes for gas-bearing and outburst formations extraction, pillarless technology for security of development workings and advanced technological schemes for second working operations.
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