Oxidation of fresh coal in the low-temperature region involves a series of processes. This starts with the adsorption of oxygen on the available fresh coal pore surfaces and continues with the high rate oxidation of coal. A new reaction kinetics expression has been proposed covering the whole low-temperature region of coal self-heating. Also, a comprehensive evaporation/drying model has been developed and validated to express the moisture removal rate of coal during self-heating. By combining these two improvements for describing the self-heating process a more robust mathematical model has been developed. Calculations have been carried out using an arbitrary-precision arithmetic algorithm in MATLAB. The model predictions have been validated by the actual moist coal self-heating behavior in an adiabatic oven.