A method has been developed, by which the tar producing propensity of coal (Fischer assay) can be assessed from a single trace of a thermogravimetric simulation of the proximate analysis of coal. It was found that, for a suite of 22 South African coal types under well defined experimental thermogravimetric conditions, the mass loss observed in the temperature interval of 460-510degreesC is related to the Fischer assay by the formula: Y = 1.17X-2.0 where Y represents the expected Fischer tar and X represents the observed mass loss in the 460 and 510degreesC temperature interval as calculated on a dry, ash free basis. The co-efficient of correlation, r(2), was found to be >0.91. (C) 2004 Elsevier Ltd. All rights reserved.