Using the van Krevelen diagram (atomic O/C vs H/C) and by plotting calorific value vs volatile matter, Australian coals, ranging in age from Permian to Miocene, were analysed. In the van Krevelen diagram method groups of coals of particular ages or from particular areas/seams within coalfields plot in well-defined parts of the diagrams. The findings and an evaluation of the analyses are presented in this article. 99102336 Changes in the structure of coals of different rank due to oxidation-effects on pyrolysis behavlor de la Puente, G. et al. J. Analysis Appl. Pyrolysis, 1998, 47, (l), 33-42. An analysis of the relationship between structural changes due to coalification and oxidation, and the modification of pyrolysis behaviour of coals. Five coals were used, ranging in rank from high-volatile bituminous to semi-anthracite. Information about changes in functional groups was obtained using Fourier transform infra-red spectroscopy (FTIR) and the pyrolysis behaviour of the coals was evaluated by means of DTA. A possible parameter indicating coal rank is the temperature of maximum volatile release. Oxidation resulted in an increase in carbonyl and carboxyl functionalities, while both aliphatic and aromatic hydrogen declined. The oxygenated groups present in the structure of the coals led to an increase in the percentage of volatile matter released in the low temperature range. Results showed that the reactivity of aliphatic hydrogen plays a major role in pyrolysis behaviour in the intermediate temperature range. At high temperatures. the relative proportion of volatile matter evolved may bear relation to the proportion of aromatic hydrogen. From the relative amount of volatiles released during the various stages of pyrolysis, a classification of coals that reflects rank and oxidation degree can be formed. 99102337 Characterization of the ash deposits from AFBC system using thermal techniques