Supervisory control at salvador flotation columns

The experience of developing, implementing and evaluating a hierarchical control strategy in a flotation column circuit at Salvador is discussed. The supervisory control system was installed in two columns in the copper cleaning circuit. Salvador concentrator produces over 200,000 tons per year of 30% copper concentrate.The column control is organised at two different levels: regulatory and supervisory control. The supervisor, SINCO-PRO, was developed to consider mainly three aspects: process data validation, metallurgical objectives control and operating problems detection. The system was installed in August 1997, and fine-tuning, was completed in October 1997. Evaluation of the new implemented system was performed in November and December 1997. The main results were an average increment in the concentrate grade of 1.2% without loss in process recovery, and a decrement in the standard deviation of the concentrate grade from 0.9 to 0.7 %. The global operation of the cleaning circuit was stabilised, increasing the average feed grade from 8 to 10 % and dramatically reducing its standard deviation from 1.8 to 0.4 %. This stabilisation of the whole circuit allowed a tighter pH control with a significant reduction in chemical reagent consumption. The project was paid during the first two month of the evaluation period.