As a result of significant research including an ACARP project and ongoing consultancy work at UQ’s Spontaneous Combustion Testing Laboratory, the database on coal R70 self-heating rates throughout Australia and overseas (New Zealand, the US and Indonesia) has rapidly expanded.
The range of coals that have been tested enable detailed benchmarking to be performed and in several cases minesite specific predictive equations have been developed. In addition, some anomalous coals have been identified from the R70 testing.
A key finding of this work is that there is a need to review the propensity classification using the R70 parameter, which now extends to values as high as 35ºC/h. A new classification scheme is being used at UQ, see accompanying table – Inherent Spontaneous Combustion Propensity (ISCP) Classification.
It should be noted that the rating scale is not linear and lignite is not class VII but class V. All classes have mining analogues for comparison.
There has been a high demand for test work over the last six months at UQ with the booming coal industry assessing new deposits and several mines taking advantage of the opportunity to benchmark their coals.
Two research projects are also scheduled this year. One will investigate the self-heating rate variation between adjacent seams and the other will study the self-heating rate differential in a coal roof.
