The ‘times to ignition’ theory has had limited use in the coal industry and virtually no use within Australia. The concept was originally applied to a range of Scottish coals to assess their spontaneous combustion propensity during transport in a 3x3m shipping hold. This paper presents results from an investigation into the application of the times to ignition (tad) concept to a range of New South Wales coals using data obtained from adiabatic oven self-heating tests. There is a strong association between tad and the R70 self-heating rate of a coal. The geographical location of the coal has a dramatic effect on the tad value as the initial coal temperature significantly changes the results by varying degrees.