High quality char, produced during the initial coal gasification process, is commonly utilised as a reductant during the smelting of chromite ores. The rate of the gasification reaction and gasification performance will depend on the relevant coal properties. These properties include organic and inorganic composition, coal porosity and pore size distribution, permeability, swelling index and intrinsic reactivity. Quantitative evaluation of these factors affecting the behaviour of coal during pyrolysis and the subsequent influence of those properties on the reactivity of the char product is of paramount significance to further our understanding of the natural differences inherent in coal. X-ray computed tomography allowed three-dimensional characterisation of pores, organic and inorganic constituents. Pyrolysis of coal resulted in increased pore volumes, and by extension, increased porosity. However, the percentage increase in porosity differs from sample to sample, which may be related to the volatile matter content of the coal. The widening and cleanup of pores during gasification result in a decrease in organic content. The organic phases will influence the behaviour of mineral matter during pyrolysis, since the former will fluidise and become devolatilised, while the mineral matter will not become fluid or volatilise, therefore the minerals will migrate and settle and, ultimately, form agglomerates. The lack of significant swelling in the TBI sample may suggest that higher levels of inertinite were present in the sample, while increased amounts of swelling in the TB2 and TB3 samples may result from increased levels of vitrinite, with the TB3 sample possibly containing the largest percentage vitrinite. The proportion of porous chars will increase with increasing vitrinite content in the parent coal, and therefore, since the TB3 char is highly porous, the possibility that the TB3 sample contains a high proportion of vitrinite becomes highly probable. However, these results need to be verified by quantifying the maceral phases through petrographic analysis. Nevertheless, inherent differences in the nature of coal will result in differences in behaviour when subjected to gasification. Although X-ray computed tomography could be used to successfully identify and quantify various properties within a sample, some limitations still remain. Further work utilising complementary techniques is required to positively identify the remaining unknown phases as well as quantify the organic components. (C) 2013 Elsevier Ltd. All rights reserved.