PRACTICAL APPROACH TO DIGITAL CONTROL OF A GRINDING CIRCUIT AT BRENDA MINES LTD.

The events which led to computer control of the grinding circuit at Brenda Mines are described, beginning with mill operating philosophy. Circuit testwork combined with an analysis of operating data show that (1) metallurgical personnel at times can increase production rates by as much as 10% over that achieved by grinding operators; (2) the chosen data base required an increase of 2% or more to be statistically significant; and (3) for a 2% increase there would be a significant rate of return of investment in computer installation. Consequently one grinding circuit is fully instrumented, and a rented computer is installed by Brenda personnel. Work is being completed for the permanent installation of computer control on all four grinding circuits at the present time. Long-term objectives are (1) off-line analysis of the circuit using mathematical models of process units; (2) on-line experiments to study alternative control tactics; and (3) possible expansion of computer facilities to the crushing plant.