Variation in apparent recovery in CIL/CIP plants Part 2 – model limitations,operating parameters and ore properties

Abstract

This paper examines the effect of a number of ore and plant variables on recovery in a CIL/CIP plant. Data collected on samples composited over 12 h periods from approximately 12 months of operation were adjusted to compensate for the delays and mixing in the plant which produce a disconnect between feed and tailings in the same period. The adjustment method used was described in Part 1 of this paper. The adjusted data were shown to provide a meaningful calculation of recovery in the plant period by period with major reduction in variation in the calculated recovery. This opened the possibility of further analysis of the variations in recovery to examine the influence of other variables. The adjusted data were tested for validity in a number of ways thereby showing that deficiencies in the model and adjustment method were responsible for very little of the remaining variation in recovery. Solution loss, residence time and particle size were all shown to have a significant influence but the effect of changes in head grade was dominant. In all approximately half the remaining variance could be accounted for. While these results are specific to the plant studied they demonstrate that the adjustment technique is able to open the way to both more immediate interpretation of recovery data leading to better control and to more meaningful and detailed analysis of the plant behaviour opening the way to more effective optimisation.