Influence of face advance rate on geomechanical and gas-dynamic processes in longwalls in gassy mines

The article highlights currentness of studies into the influence of mine production rate on geomechanical and gas-dynamic processes in longwalls. It is shown that, despite the quick pace improvement in mining technique, there is essential backwardness of methodical and regulatory framework used to determine basic parameters of geomechanical and gas dynamic phenomena. The normative documents currently in force in Russia in calculating main roof caving steps in longwalls and the earlier research data on influence of longwall face advance rate on rock pressure phenomena in are analyzed. The research findings on undulating nature of change in methane content in high-production longwalls, which is related with movement processes in undermined rock mass, are examined. The field studies carried out in Zapolyarnaya Mine, Vorkutaugol reveal disagreement between the actual and calculated steps of main roof caving and recommend on improvement of the current calculation procedure. In Kotinskaya Mine, SUEK-Kuzbass, investigations of methane emission in longwalls determine the periodic nature of methane release maximums along a longwall panel. As the main causes of wide variation range of roof caving span (25–40 m), the authors show variable lithilogical composition and strength characteristics of roof rocks along longwall panels, significant range of output per face and the presence geological discontinuities. The future directions for research aimed to enhance safety and efficiency of high-production mining in series of gasbearing coal seams are defined. The authors express their deep gratitude to A. M. Cherdantsev, Chief Engineer, Yalevsky Mine, for the assistance in collection and processing of mine data, and for the participation in the research of influence of longwall face advance rate on geomechanical and gas-dynamic processes in longwall panels.