An investigation of large scale industrial crushing and screening operations

The behaviour of gyratory (including cone) crushers and vibrating screens have been investigated in detail through experimentation carried out on laboratory, pilot and industrial scale equipment. The industrial data were used to develop mathematical models of operating units. The laboratory and pilot data were used to examine the mechanisms involved in crushing and screening, extend the range of information on the effects of various material, operating and design parameters and to verify the forms of model developed.The models derived from this work were then used in steady-state simulation studies of the primary-secondary and tertiary plants of a large crushing and screening operation. Analysis of the simulation data has resulted in1. changes in the day to day operating philosophies at these plants,2. clear policies which are employed to make changes in the product when required or to counteract variations in the new feed, and3. development of automatic control systems for implementation by a small process control computer.The effectiveness of the control systems developed were examined using a technique derived for assessing crushing plant control system design. This technique employs a dynamic simulation model of crushing circuits.Finally, the use of simulation models in crushing circuit analysis was extended to the design of a crushing and screening plant. A technique has been derived whereby multiple circuit configurations can be accurately evaluated using only limited data resources. This technique has been applied to the design of a proposed large scale crushing and screening operation.