Comparison of the R70 self-heating rate of New Zealand and Australian coals to Suggate rank parameter

Samples from New Zealand and Australia have been tested in an adiabatic oven to assess the effect of rank on the R70 self-heating rate of coal. A non-linear relationship can be defined for coals from both countries using the revised Suggate rank (Sr) parameter. Subbituminous coals have the highest R70 self-heating rate values, which are 20 times that of high volatile A bituminous coals on a dry mineral matter free basis (∼ 1 cf. 20 °C h− 1). However, the moderating effects of moisture and mineral matter can reduce this difference to only 2-3 times for coal in-situ.