Experiences of gripper TBM application in shaft coal mine: A case study in Zhangji coal mine, China

TBMs had been introduced to coal mining industries for decades. However, the applications of TBM in coal mines which have vertical shafts as their main accesses were barely reported. This paper presents a case study of TBM tunnelling works in Zhangji coal mine, China. The roadways, having diameter of 4.53 m and average buried depth of 500 m were excavated by a gripper TBM. Before the TBM excavation works, TBM delivering from surface to underground working site through vertical shaft and assembling TBM within roadways were taken into account. The problems encountered during the TBM tunnelling such as weak grounds, coalbed methane (CBM) inflow and abnormal cutter wear are discussed. In addition, solutions and remedial works of each problem are proposed. Consequently, the downtimes of TBM were reduced significantly and the average penetration rate increased from 5 to 8 m/d to 18.67 m/d and the highest penetration rate of 30.7 m/d was obtained. The working experiences indicate that with proper modifications on TBM configuration and excavation techniques, TBMs are able to provide a safety, efficient and competitive alternative to roadway excavation within shaft coal mines.