The present paper reports the results of Mossbauer spectroscopic investigations of the transformations of different iron-bearing minerals in some Indian coals of different geological origin with varying mineral contents during their ashing and pulverised fuel combustion (PFC). The iron-bearing minerals thus characterised in the coals include Fe2+-illite (Lodna, Jammu and Singareni coals); pyrite (Jammu, and Singareni coals, in the latter in association with marcasite); siderite (Lodna coal); ankerite (Singareni coal); and szomolnokite (Jammu coal). The corresponding ashes produced after ashing at 800 degrees C are found to contain in general, Fe3+-glass silicate and haematite, with additional species of magnesioferrite in Singareni coal ash, wherein Fe3+-glass silicate is the decomposition product of Fe2+-illite, and haematite is that of oxidation of pyrite and siderite, magnesioferrite being derived from ankerite. Quite different from this, the Mossbauer spectra of the fly ashes produced as a result of PFC in Vijayawada and Kothagudam Thermal Power Stations are very complex, comprising superimposed sextets and doublets of oxides (haematite, magnetite, goethite), Fe3+-silicate and Fe3+/Fe2+-mullite, indicative of local nature of combustion (viz. method of firing, mineralogy of coals, as well as residence times of coal particles in the flame zone) via intricate mineral interactions during PFC in lower and higher temperature zones under both oxidising and reducing conditions. These studies thus provide clues to the reaction pathways during the combustion process.