The present study examines the reflectance and petrology of a self-burning coal wastepile from Coleman, Alberta, Canada. Unaltered coal, carbonization, combustion and ash zones have been identified in the section studied. Due to the presence of uncompacted coal fragments, air can circulate easily through open fractures acting as conduits for convecting gases. Heat generated by the combustion of coal has altered the coal to produce solid (semicoke/coke), liquid (tar) and volatile matter. Several types of tar have been recognized penetrating cracks in the residues, briquetting coal macerals or reacting with coal particles. It has been estimated that the coal was carbonized at a temperature of 500–550°C at a rate of heating of 10°C/min and subsequently combusted at a higher temperature (550–600°C). When comparing the optical and petrological profile of the Coleman self-burning coal wastepile with that of other burning coal seams in Western Canada, certain similarities and differences become apparent.