白云乌素煤矿奥陶系顶部碳酸岩层隔水性及应用研究

为了解决内蒙古桌子山煤田下组煤安全带压开采问题,依据多年研究成果—"华北奥陶系顶部存在碳酸盐岩隔水层"观点,选择与骆驼山煤矿相邻的白云乌素煤矿为研究试验现场,对下组(16#)煤底板岩层开展了宏观、微观研究和试验开采,结果表明:1)本区煤层底板下伏的奥陶系顶部存在碳酸盐岩隔水层厚约150 m,其岩性为黑灰色泥灰岩局部夹泥岩沉积,真正含水层段在其下的桌子山组青灰色白云岩化石灰岩中;2)克里摩里组黑灰色泥灰岩孔隙直径绝大多数小于5μm,孔隙连通性差,难以形成有效孔喉,天然条件下难以渗流;3)本区新构造运动的表现是大型老断裂的复活和部分小型新断裂的产生,断裂为碳酸盐岩层岩溶发育提供初始通道,也构成岩溶水的主要储移空间和通道;4)桌子山矿区奥灰岩溶水对煤矿安全带压开采的主要威胁是导水断裂和陷落柱等垂直通道部位,白云乌素矿重点防御的是黑龙贵逆断层和F14正断层。白云乌素矿多个工作面的安全开采证实了奥陶系顶部碳酸岩层不仅是隔水层,而且是隔水关键层。

Research on Water-Resisting Property of Top Carbonatite Strata of Ordovician in Baiyunwusu Coal Mine and Its Application

In order to solve the problem of mining safety under water pressure of aquifer in lower coal group of Zhuozishan coalfield in Inner Mongolia,so based on years of research-"Top of Ordovician exists carbonate aquifuge in North China",Baiyunwusu mine which is nearby Luotuoshan mine is chosen as the field test in-situ,to carry out the macro-and micro-researches on the floor of lower coal seam(16 #) and test mining.The results show that: 1) There is a layer of carbonate aquifuge,with 150 m in thickness,existed in the top of Ordovician underlying coal seams floor,while the lithology is dark gray marl with less mudstone deposition.Meanwhile,the real section of the aquifer is appeared in caesious dolomitization of limestone under-laied the dark gray marl strata;2) The vast majority of pore diameter of dark gray marl in Kelimoli group is less than 5 μm.Because of the poor pore connectivity,the effective pore is difficult to be formed and it is hard to seepage in nature;3) The performance of the new tectonic movement is the resurrection of large old fault and generation of some small new fractures.Besides,the fractures provide the initial channel to Karst development and also constitute the main Karst water reservoir shift space and access;4) The main threaten of Ordovician Karstic water to safety mining under water pressure of aquifer in Zhuozishan coalfield is hydraulic conductivity fracture,collapse column and other parts of the vertical channel,and the key area to control water inrush is Heilonggui thrust fault and F14 normal fault.Eventually,the safety mining in many workfaces in Baiyunwusu mine confirms that the top of Ordovician carbonatite strata is not only the aquifuge,but also the key aquifuge.