Document Type
Conference Paper
Publication Date
2019
Abstract
The Broadmeadow punch longwall coal mine in Central Queensland Australia has experienced significant highwall movement associated with the effect of longwall subsidence when the longwalls approach their final position close to the open cut highwall. In response to this movement Broadmeadow employed two types of broadscale highwall monitoring (radar and laser scanners) to provide full coverage measurement throughout three consecutive longwalls approaching the highwall. This was to attain a better understanding of the mechanism causing the movement and potentially enable prediction of instability. Results from the monitoring found the highwall is displaced to magnitudes unlike those typically measured in open-cut mining, and in direct contrast to typical longwall subsidence behaviour. This paper discusses the ground movements measured, monitoring methods used, safety measures established as well as theorising the failure mechanism. Recommendations are made for mine and pit designs for future punch longwall layouts. The paper shows how the movements measured are more aligned to some measurements made during stream valley closure studies previously presented at the International Conference on Ground Control in Mining (ICGCM) and challenges the mechanisms suggested by previous literature.
Publication Details
Dan Payne, Matt Martin, Bob Coutts, Dan Lynch, Highwall stability implications from longwall mining at Broadmeadow mine, in Naj Aziz and Bob Kininmonth (eds.), Proceedings of the 2019 Coal Operators Conference, Mining Engineering, University of Wollongong, 18-20 February 2019, 91-102.