A coal burst occurred in a development unit. The unit stopped and workers were removed from the area. The area was secured and the workers were uninjured. A large scale ‘pressure bump’ resulted in the displacement of coal from the rib over a distance of approximately 3m. Workers at the face observed the ejection of coal, however did not immediately recognise it as a coal burst. An independent geotechnical engineer and the mine’s geotechnical engineer inspected the area and determined the incident to be a coal burst. Normal mining production was taking place at the time. The area is heading towards the swamp fault zone and had reduced the spacing’s between the cutting test as per the mine’s plan. A cutting test was taken 1 m before and was deemed to be okay.
Recommendations to industry: Mine operators are reminded of the obligations under WHS (MPS) Regulation 2014 clause 44B – Mining induced seismic activity.
The predictability of coal burst is not precise and, as such, mine operators should consider that where an increased coal burst potential has been identified, due to the presence of geological structure or change in stress regime, control measures should be implemented that remove workers from the place of risk.