Underground » Coal Burst
Coal burst is a violent collapse of the coal wall or roof in development, roadways and at the longwall face in underground coal mines. Because it occurs suddenly, with no or very little warning, coal burst is particularly dangerous to nearby mine personnel, mining equipment and infrastructure. A damaging coal burst can cause significant risk to the underground workforce, equipment and production.
It is widely accepted that coal burst is a dynamic failure process mainly driven by in-situ stress that accumulates during mining in the coal seam and nearby geological structures. Fractures and sudden strain release in the coal seam and adjacent roof and floor would occur before coal burst. This dynamic process, disturbance of the fractures and changes in strain release have microseismicity 'fingerprints' or indications.
The aim of this project was to investigate possible correlations between microseismicity and coal burst events for monitoring and prediction. This first stage of the project covered the following work programs:
- Installation of CSIRO microseismic monitoring systems at three underground coal mines with different coal burst hazard rankings and collection of data for future coal burst research.
- Documentation of the microseismic data sets and related geology and mining process data and make them available for scientific use for coal burst research.
- To perform preliminary data processing and evaluation, and provide recommendations for research in the next stage.
Three coal mines in New South Wales were selected as experimental sites for data collection and research:
- A - ranked as a site with high coal burst risk;
- B - ranked as a site with medium coal burst risk;
- C - ranked as a site that has no coal burst risk.
The microseismic monitoring programs conducted at the three coal mines have demonstrated the usefulness of microseismic techniques for monitoring microseismic events in the coal seam and its adjacent rock mass, near roadways and significant geological structures. These events can be used to infer stress conditions inside the seam and map coal weakening processes that may lead to coal burst.
The microseismic data and mine operation data collected from the three mines are valuable for coal burst research and they are available for use by the scientific community.