Application of laser scanning to measure fragmentation in underground mines

The particle size distribution of fragmented rock in mines affects operational performance of loading equipment, materials handling and crushing systems and is known to influence ore flow in caving mines. A number of methods to measure rock fragmentation exist at present, however these systems have a number of shortcomings in an underground environment. This paper outlines the first implementation of high resolution 3D laser scanning for fragmentation measurement in an underground mine. The system is now used routinely for fragmentation measurement at the Ernest Henry sublevel cave mine following extensive testing and calibration. The system is being used to study the effects of blasting parameters on rock fragmentation to optimise blast design. Results from 125 three dimensional scans measured the average P and P to be 230\ua0mm and 400\ua0mm respectively. The equipment, methodology and analysis techniques are described in detail to enable application of the measurement system at other mines