The Use of Cribless Tailgates in Longwall Extraction

摘要

The paper defines the various operational advantages associated with the use of cribless tailgates during longwall extraction and considers the associated ground control issues that need evaluating to ensure a successful outcome. Reference is made to longwall mines in Australia currently using cribless tailgates and the geotechnical and ground support factors that allow them to do so. This includes the nature and behaviour of the roadway roof, the stability of the chain pillar and also the type and timing of installed support. A specific case history from a colliery in NSW will be referred to whereby heavy standing support was replaced with lower density tensioned cables as routine TG secondary support, which resulted in both improved TG roof conditions and a significant cost reduction. The conclusion will be drawn that cribless tailgate roadways can potentially be used in many environments either due to the existence of highly competent immediate roof conditions or through the appropriate application of active reinforcing support measures in less competent conditions. Use will be made of Strata Engineering's roof behaviour and stability model in demonstrating the various concepts involved.