In a metal processing facility, the final tailings slurry produced by the process is thicken in a caisson and thickener and pumped out of for disposal. The density of the slurry that leaves the thickener must be maintained at a set point of 75%. Proximity switches are installed on the outlet pipe is either open or closed. The pump drive for pumping the slurry out of the thickener is 3Ph ac induction motor variable speed drive rated at 150kW, 415V, 50Hz. The speed of the 150kW pump drive is controlled by by the density of the slurry in the pipe. using a block diagram show the control loop for thr mention process