A case study of the stability of a non-typical bleeder entry system at a U.S.longwall mine  

作　　者：T.M.Klemetti M.A.Van Dyke I.B.Tulu D.Tuncay 

机构地区：[1]NIOSH Pittsburgh Mining Research Division,Pittsburgh 15236,USA [2]Department of Mining Engineering,West Virginia University,Morgantown 26505,USA

出　　处：《International Journal of Mining Science and Technology》2020年第1期25-31,共7页矿业科学技术学报（英文版）

摘　　要：Longwall abutment loads are influenced by several factors,including depth of cover,pillar sizes,panel dimensions,geological setting,mining height,proximity to gob,intersection type,and size of the gob.How does proximity to the gob affect pillar loading and entry condition?Does the gob influence depend on whether the abutment load is a forward,side,or rear loading?Do non-typical bleeder entry systems follow the traditional front and side abutment loading and extent concepts?If not,will an improved understanding of the combined abutment extent warrant a change in pillar design or standing support in bleeder entries?This paper details observations made in the non-typical bleeder entries of a moderate depth longwall panel—specifically,data collected from borehole pressure cells and roof extensometers,observations of the conditions of the entries,and numerical modeling of the bleeder entries during longwall extraction.The primary focus was on the extent and magnitude of the abutment loading experienced due to the extraction of the longwall panels.Due to the layout of the longwall panels and bleeder entries,the borehole pressure cells(BPCs)and roof extensometers did not show much change due to the advancing of the first longwall.However,they did show a noticeable increase due to the second longwall advancement,with a maximum of about 4 MPa of pressure increase and 5mmof roof deformation.The observations of the conditions showed little to no change from before the first longwall panel extraction began to when the second longwall panel had been advanced more than 915 m.Localized pillar spalling was observed on the corners of the pillars closest to the longwall gob as well as an increase in water in the entries.In addition to the observations and instrumentation,numerical modeling was performed to validate modeling procedures against the monitoring results and evaluate the bleeder design.ITASCA Consulting Group’s FLAC3D numerical modeling software was used to evaluate the bleeder entries.The results of the models indi

关 键 词：ABUTMENT LOADING LONGWALL Instrumentation BORE hole pressure cells PILLAR LOADING Yield PILLAR Bleeder PILLAR 

分 类 号：TD82[矿业工程—煤矿开采]