Real time dynamic-simulation provides a powerful tool to control the mineral processing plants with the minimum cost. In this study, the dynamic simulation was carried out for the thickener at coal washing plant. Therefore, the parameters of the phenomenological model for the sedimentation and thickening were determined at different conditions. Dynamic simulation was carried out for each condition and the effect of feed flow rate variations on solid volume fraction of the thickener underflow and bed height was investigated. For all conditions, it was observed that when feed flow rate increases, the solid volume fraction of discharge and bed height increase. It was also observed that, in the case of the flocculated suspension, the maximum solid volume fraction of-the thickener underflow decreases and the bed height increases with pH reduction, for two size fractions. Also, the maximum solid volume fraction of the thickener underflow for d(80) = 275 mu m is higher than that of d(80) = 125 mu m and the height of compression zone for d(80) = 125 mu m is higher than that of d(80) = 275 mu m at the certain pH and flocculant dosages. (C) 2016 Elsevier B.V. All rights reserved.