On the spontaneous combustion liability of South African coal: a report

Coal fires around the world are challenging and recurrent problems anywhere coal is being mined, processed, stored and transported. Coal spontaneous combustion (SPONCOM) is the reason behind most of these fires. Therefore, when taking preventive actions against the risk of coal fires, it is essential to evaluate their degree of liability to avoid the loss of valuable and unrenewable resources acquired by the mine. The self-heating characteristics of coal is an issue that concerns the mining industry not only in South Africa but also in many other countries. This study reports the database of SPONCOM liability of 442 coal samples collected at various coalfields in South Africa between 2010 and 2020 using the Wits-Ehac testing method. The Wits-Ehac test results were found to match with the reports from the Coalfields. Out of the 442 coal samples evaluated, 11 samples had low liability values, 306 samples had moderate liability values, while 125 samples had high liability. The system for classifying the liability of coal samples toward SPONCOM in this study is very generic, works well for coalfields in South Africa and would be useful for planners and field engineers to take corrective steps in advance to prevent mine fires from occurring.