Research On Weakening Technology Of Top-coal Caving Mining Of Tun Bao Mine

The weakening technology of coal injection is an effective technical way to improve thecaving of hard thick (gas) top-coal, treat the hard roof, prevent the rock burst, improve seampermeability and prevent the outburst of coal and gas, is a safe and efficient securitytechnology of coal mine exploitation, with the advantages of safety, environmental protection,efficiency, economy. Reasonable water injection parameters are the key of a good weakeningeffect which the water injection of coal seam takes. The research on reasonable waterinjection parameters can not only effectively improve the recovery rate, it also savemanpower and material resources to achieve safe and efficient purpose.Studied by orthogonal test, theoretical analysis, numerical simulation and field trials andother research methods Tun Bao mine hard top-coal injection weakening technology for amore systematic study, the major work done and the results are as follows:(1) The use of similar material simulation analysis Tun Bao mine overburden cavingprocess and the deformation and failure process.(2) Gently inclined seam longwall top coal caving form along the face tilt direction wasasymmetric arched characteristics, in face length under certain conditions, the angle of coalseam top coal strength, mining height is the roof fracture height (Σhmax)maximum breakingheight from the the face lower exports distance of (x0) the main factors of various factors onthe impact of Σhmax: angle of coal seam top coal strength coal mining height; x0degree ofinfluence: top coal strength>strata dip> coal mining height.(3) Proposing and implementing a steep seam fully mechanized caving face top coalweaken ahead of pre-injection technology to optimize the injection process and parameters.(4) Weakening tests of hard top-coal the coal have shown that,water injection weakensthe whole mechanical property of coal mass and reduces the size of top-coal broken and increases recovery ratio of top coal by19%,the production of raw coal320t/d. It can reduce23%of dust concentration，and suppress coal spontaneous combustion.