Improving shield supports for mining thick steep seams

Conclusions  

Creation of a powered complex for mining thick steep seams with hydraulic fill

Parameters are determined for a technological scheme and a powered complex for mining thick steep seams under objects which are to be protected. The seams are mined by strips along the strike with the use of hydraulic fill. The possibility of constant maintenance of coal and filling masses in the steady state by using this complex is considered. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 93–102, July–August, 1999.     

急斜特厚煤层群采动应力畸变致诱动力灾害控制

采动应力诱发的动力灾害是制约急斜特厚煤层群安全开采的难题之一。以乌鲁木齐矿区乌东煤矿动力灾害防控为目标,采用开采技术条件调查、理论分析、数值计算和现场监测等方法与手段,揭示采动应力畸变致诱动力灾害机理。研究表明:43号煤层产生的采动应力经其顶煤传导作用至层间夹持煤岩柱(sandwiched coal-rock pillar in seams,SCPS),同时受自重作用SCPS发生大变形,造成其倾向上部层位受拉伸应力而倾向下部层位受压缩应力,引发45号煤层+575水平南巷顶板应力高度集中,导致动力灾害频发。针对43号煤层工作面高于45号煤层工作面的开采布局,制定"先注水后爆破"解危措施。现场监测结果表明微震大事件频率由4.0次/min降至1.0次/min,电磁辐射峰值强度降至42.8 m V,动力灾害得到有效控制。     

急斜厚煤层分层与分段放顶煤岩层移动对比

运用相似材料模拟和数值计算的方法,对水平分段和倾斜分层放顶煤开采引起的围岩移动特征进行了比较.倾斜分层开采引起的地表下沉盆地倾向主断面水平宽度大,而垂直移动和水平移动量小,水平分段开采则相反;倾斜分层开采时,上覆岩层先弯曲离层,再断裂垮落,易形成铰接结构;水平分段开采时,上覆煤岩易发生巨型块滑动式垮落;倾斜分层开采时,采空区垮落带高度小,水平分段开采时垮落带高度大.倾斜分层开采可以减轻围岩垮落和地表移动的强度.     

急斜煤层(群)水平分段顶煤超前预爆范围综合确定

基于理论分析、地质环境与开采条件调查,构建了煤岩断裂与失稳多元指标监测方法。通过钻孔应力计、光学钻孔窥视仪和顶煤松动范围监测等进行实测,综合对比分析超前预爆破中顶煤应力与变形规律。最终确定超前预爆破范围为10.0~35.0 m,支护范围为0~45.0 m。     

急斜近距煤层联合开采矿压显现规律

乌鲁木齐矿区赋存有30多层急斜煤层,其中南区的B7～B34就有多组近距离煤层,一直是开采的难题。近年在这类煤层发展了近距煤层联合布置水平分段放顶煤开采,本文介绍了矿山压力观测的主要成果,并通过三维数值模拟,对围岩应力进行了初步分析。