The improved ash fusion test has been found to be a useful tool for correlation with ash behaviour in power stations, The improved ash fusion test monitors the ash behaviour in the standard ash fusion test furnace and allows some interpretations on the ash fusion temperatures and ash stickiness. The results of a survey sent to nine Australian power stations on general slagging experience of the main feed coals were compared with the results of the improved ash fusion test. Comparison showed that improved ash fusion test indexes reasonably correlated with perceived performance of the coals in the power stations.