Five ultra fine bituminous coals from the Witbank coalfield were studied. Selected chemical and physical properties, coal petrographic characteristics and mineralogical compositions of the coals were measured. The coals were compacted, using a briquetting press, at various feed moisture contents. The formed briquettes were then tested for compressive strength and water resistance and the values correlated with the coal characteristics and the briquetting conditions. The coals were found to be amenable to conventional binderless briquetting. The bonding in the briquettes was found to be due mainly due to the impurities in the coals, particularly kaolinite. This may add a new perspective to the fundamentals of the binderless briquetting of bituminous coals. (C) 2004 Elsevier B.V. All rights reserved.