Analysis of Bulli Seam Benchmark and DRI to Determine Outburst Threshold Limits

Following the introduction of the Desorption Rate Index (DRI) and Bulli Seam Benchmark to the Australian coal industry in 1995, the use of the DRI900 method was adopted and continues to be used as the primary method to assess outburst risk and to determine gas content threshold values for outburst risk management in Australian coal seams. In addition to assessing outburst risk based on gas content threshold values, several Australian coalmines also include DRI900 as a threshold level in assessing outburst risk. It is apparent that there is a broad lack of awareness and understanding of the limitations and deficiencies of using DRI to assess outburst risk and to determine appropriate outburst threshold limit values. A comprehensive set of gas test results from Australian coal seams has been collected as part of research into control and management of outburst risk in Australian underground mines and the results of specific investigation into DRI and its applicability for use in assessing outburst risk and determining appropriate gas content threshold levels has identified significant deficiencies which are presented and discussed.