Abstract
The self-heating of coal due to oxidation potentially leading to its ignition is called “spontaneous combustion”. The characterisation of the physical and chemical properties of coal on a standard provides an understanding of its characteristics towards spontaneous combustion. The liability of coal to undergo spontaneous combustion for selected coal samples obtained from the Witbank Coalfields was examined using different spontaneous combustion tests. The simple indices [crossing point temperature (XPT) and Stage II Slope] obtained from differential thermal analysis and composite indices [FCC (Feng, Chakravorty, Cochrane) and Wits-Ehac Indices] were used to examine the liabilities of 30 coal samples. The test results are examined and presented according to the readily recognisable characteristics known to be indicators of self-heating liability. Two characteristics obtained from a differential thermogram (XPT and Stage II Slope) are evaluated as indicative of the liability of coal to self-heat. The simple indices provide inconsistent predictions of spontaneous combustion liability, while the composite liability indices provide more reliable results...
M.Tech. (Extraction Metallurgy)