Since outburst threshold limits were imposed on Bulli seam mines in 1994 the occurrence
of coal and gas outburst incidents have virtually been eliminated from the Australian coal industry. With
the reduction in incidents and therefore hazard to the industry there has been a corresponding drop in
research effort in this area. Some mines have in recent years reviewed and raised threshold limit
values and non-Bulli seam mines accept the method of threshold limit value determination introduced
by GeoGAS, based upon the DRI900 concept.
Detailed analysis of gas desorption data from a variety of Australian coal mines, representing different
coal seams with variable gas content, gas composition, rank, type, structure,
etc., has been undertaken
and the results indicate significant relationships which impact the accepted method of outburst
The relationships are discussed and a new method
of determining outburst threshold limits, applicable
to non-Bulli seam mines is presented.