Study On Water Conservation Mining And Safe Mining With Superhigh-water Material

For the mining of coal under water and threat of water inrush from coal floor，Super-high-water Material filling mining is one of the important technical means ofgreen mining of this part of the resources. Based on the previous research，byelastic-plastic theory and establishment of mechanical model，Authordeduces anddetermines the failure process of coal roof and floor during Tian Zhuang mine1611working face mining，then verified by empirical formula，Necessity of filling miningis proved. This article systematically analyzes laws of various factors that affect thedamage range of coal roof and floor. On the base of these studies，Mechanism thatfilling body act on protecting coal roof and floor is made clear and obtains thefollowing research results:(1)Based on the Key Strata Theory，make a distinction between key stratum andsoft stratum, then use different criterion to determine if stratum are of waterconductivity. According to this theory，if16upcoal is mining through caving method，water flowing fractured zone will reach52meters high, matching the results ofempirical formula，which is30.6~48.4meter.(2) Based on the theory of plasticity and elasticity, if16upcoal is mining throughcaving method，the floor breakage depth will reach6.0meters deep，matching theresults of empirical formula，which is6.8~13.1meter. Through the Three UnderlyingBelts Theory and water-bursting-coefficient method, water bursting coefficient willbe0.07~0.12MPa/m，which is more higher than0.06~0.10MPa/m provided byregulations, so it is with the threat of water bursting to mine16upcoal through cavingmethod.(3) Summarizing the influence factors of the roof and floor damage range incaving mining, This paper emphasize that there is a positive correlation betweenmining height and floor breakage depth, if mining height is very small (hundreds ofmm). Authors suggest that Super-high-water Material filling mining eases floordamage by decreasing mining height. Based on Equivalent mining height theory，equivalent mining height16upcoal， if Superhigh-water filling mining， is1.4m~0.5m，which is27%~33%of real mining height.(4) Through numerical simulation, the contribution rate of underseepage tobreakage range is21%much than single analysis, vertical stress15%. Sounderseepage action is not to be ignored in study of water-preserved-mining and mine water prevention and control. Through coupling analysis, This paper studies theeffects of filling body strength，filling rate and unsupported roof distance to coal roofand floor breakage range. In the actual production, aiming at ensuring the main roofdestructive and aquiclude of floor thick enough to prevent water inrush，strength offilling body must be more than1MPa, filling rate more than50%~70%andunsupported roof distance less than20m.(5) The measured data show that Super-high-water Material filling mining canreduce roof and floor breakage range。At the filling working face，the floor breakagedepth is less than1~2m；the roof aquiclude is in good condition，and there is no watershow phenomenon.