Research On Pressure Control Of Lower Slice Mining Face In “Three Soft” Unsteady Coal Seam

Specially for this specific geological environment of 13012 lower slice mining face of Jiao xue NO.3 coal mine, field investigation, field observation, numerical simulation and industrial practice were used, the characteristics of pressure appearance, law of overlaying strata movement were studied.First, Through the primitive coal seam and lower slice mining area for the two-stage observing mine pressure in face, Base on above results, analysis, comparison and a good command of the characteristics of pressure appearance, law of abutment pressure, soleplate stability of working face and its content. Secondly, using UDEC numerical simulation software to establish the model, dynamic progressive process of failure of overlying rock strata caused, law of overlaying strata movement and the stress distribution of coal seam thickness of 4m, 6m and 8m by second-mining excavation through numerical simulation method are gotten. Then, to dive deep into the rock mass structures and relation of support–rock of lower slice mining face, build a proper model of support –rock, then to analyze the adaptability of cantilever support and tip support, and improvements the two types support. Finally, a scheme of dynamic top coal caving mining is designed for "three-soft" unsteady coal seam.The outcomes of this paper are guidance for smooth extraction of lower slice mining face, not only enhances coal recovery rate, and guarantee the safety and high effective product of the coal face, the successful experience can be reference and guidance to the mine areas with similar geological conditions.