Variations in the mechanical properties of coal related to structural deformation and burst events

This paper summarises the research conducted to provide a new means of measuring the burst propensity of coal. Burst events in underground coal mines are commonly associated with structurally disturbed coal. As part of this study, a series of samples were collected from burst and non-burst sites for UCS testing to identify the changing burst propensity of different seams in proximity to geological structures. Applying the three critical factors of the burst triangle, coal, energy, and isotropic mass, identifies the controlling factor of burst events to be isotropic mass. Isotropic mass influences the confinement of the coal mass and energy storage potential. The isotropic mass of a coal seam is determined using the Coal Mass Rating (CMR) derived from the UCS test results. At each site, the samples collected come from four sampling zones near various geological structures. The four zones were identified based on the fracture index of the coal. The coal with the higher CMR values provides an early indicator of pockets of stored energy, including gas and strain energy. In combination, the CMR value and the fracture index provide a means of determining the burst propensity of the coal samples, enabling early intervention prior to the occurrence of burst events.