Study On Safety Technology For Fully-mechanized Top-coal Caving Face In Steep And Extra-thick Coal Seam Of Baoji Shan Mine

Mining in steep and extra-thick coal seam have a vital significance to developing andutilizing of coal resources and make up for the shortages of energy. Study on Miningtechnology of fully-mechanized top-coal caving face is important for safe and high efficientmining in mine, to improving fully-mechanized coal minning provide technical support andtheoretical reference.The paper through analysis strata pressure behavior law of Baojishan mine704workingface, using FLAC, UDEC numerical software, research on movement, deformation andfailure characteristics of overlying strata and top coal. Base on analysis of morphologicalcharacteristics of top coal drawing body which in compaction area, completely filled and halffilled area of steep seam, using the physical simulation and numerical simulation of PFC2D,determine a reasonable coal caving step distance and caving method for704fully mechanizedtop coal caving face, and Using the self-developed top-coal movement tracker device,observes the top coal movement laws and the recovery rate of top coal in differentlayers.Based on the tests and theoretical analysis, using the static mechanics model, researchon key parameters and influence factors of support declined and overturned.Finally, combined with the type selection of support on704fully mechanized workingface in Baojishan mine, Validated working face of limit angle, the practice proved that theangle can ensure the work face support and stability. To ensure the safe and efficient production of fully mechanized top coal caving working face, to ensure efficient use of coalresources and recycling.