Document Type

Conference Paper

Publication Date


Publication Details

Jan Theiler and Basil Beamish, Spontaneous combustion hazard likelihood assessment of low reactivity coals, Proceedings of the 2024 Resource Operators Conference, University of Wollongong - Mining Engineering, February 2024, 322-325.


Risk assessment has two components, hazard likelihood and consequence. There appears to be some confusion in terminology within the coal mining industry that equates the term propensity with likelihood when assessing spontaneous combustion risk. Spontaneous combustion propensity is determined using a number of index parameters that are obtained using specific test procedures. However, the propensity ratings obtained are based on a relative scale and in isolation they are effectively only a measure of the coal intrinsic reactivity. For some indices (R70 and SHT) this reactivity measure relates to the low temperature end of the self-heating spectrum and in others (CPT) it relates to the high temperature end, which is really an indication of the ease of ignition once the coal has dried out. From a mining management perspective, operations are trying to manage and control the risk of creating a heating at the low temperature end of the scale so that they do not reach the ignition phase. This paper will present a new approach to spontaneous combustion hazard likelihood assessment of low reactivity coals using a chart that incorporates the two main heat balance factors governing self-heating over time, namely the intrinsic reactivity and moisture content of the coal. Examples will be presented of the application of this chart to site-specific hazard likelihood assessment.