In this study, a control system incorporating the know-how of the skilled operators using fuzzy logic is applied by using on-line ash monitors conventionally employed for product coal quality control as a jig control system sensor to a coal preparation plant of the Ombilin Mine in Indonesia. The computer simulation experiments demonstrate that the response can be improved by means of modification of the fuzzy rules. Based on the results of the simulation experiments, it is clear that the present proportional/integral-operation fuzzy control system is effective in mitigating the large dead times of 60 seconds due to the sampling interval of the ash monitor, and also in mitigating the parameter variations due to the properties of raw coal. The experimental results show that the coal washery jig control system developed with the use of the PI fuzzy control system is capable of controlling the clean coal ash content to within a ± 3% range of the target ash content of the clean coal.
