Outburst control in the Wongawilli seam

The Wongawilli coal seam varies from 8 m to 10 m thick and consists of interbedded bands of kaolinitic brown mudstone and coal plies. In the southern part of the coalfield, the lower section of the seam is higher quality and lower ash. Dendrobium mines the bottom 3.5 m to 4.0 m of the seam, producing hard coking coal for use in steelmaking. The Wongawilli coal seam varies from 8 m to 10 m thick and consists of interbedded bands of kaolinitic brown mudstone and coal plies. In the southern part of the coalfield, the lower section of the seam is higher quality and lower ash. Dendrobium mines the bottom 3.5 m to 4.0 m of the seam, producing hard coking coal for use in steelmaking. Dendrobium has operated in an historically low gas environment and is now transitioning into a new mining domain that presents new challenges of increasing gas content, increasing CO2 seam gas composition, and low in situ permeability. Dendrobium has an established Outburst Principal Hazard Management Plan, consistent with Industry best practice, that defines standards and requirements for (a) Predicting areas where an outburst risk may exist, (b) Preventing an outburst event from occurring, and (c) Protecting personnel from exposure to an outburst. Dendrobium’s approach to outburst control in the Wongawilli seam is explained, along with a range of initiatives to improve drilling and gas extraction, and to improve the accuracy of identifying outburst risk zones and threshold limit values.