ABSTRACT
As part of an ongoing research programme to investigate the rock mass response to mechanised pillar extraction the CSIRO designed and constructed a breaker line support (BLS) monitoring system, BLSmon. This was installed and commissioned at Laleham No.1 Colliery, at the South Blackwater Mine in Queensland. This system was designed to record hydraulic leg pressure and canopy position measurements and relay these, in real time, to the surface.
Analysis of the results of the monitoring exercise has shown that rate of change of leg pressures on the BLSs could be used as an aid in the prediction of adverse mining conditions. The rate of change of loading and convergence can be utilised to identify the onset of instability in the lift area. A mechanism has been postulated for the deformation behaviour of the roof and pillars in a mechanised pillar extraction operation from the continuously monitored data, observational data and results of previous studies. However, before this facility can be utilised by the mine for the reliable prediction of instability more monitored data and sophisticated processing techniques are required.
The potential role and application of continuous monitoring in advancing understanding of the rock mass response to mechanised pillar extraction operations has been demonstrated. This understanding now requires enhancement and shows great potential for aiding the optimisation of mechanised pillar extraction operations.
The ability to gather continuous data is only the first step, however in order to fully utilise such data in a proactive system deformation mechanisms must be well understood together with a sound knowledge of the rock mass strength and deformability characteristics. The CSIRO Mining Geomechanics Group are currently involved in a range of research projects attempting to address these areas.
