The effects of stage recovery uncertainty in the performance of concentration circuits

Abstract

This paper analyzes the effect of uncertainty in the recovery of each concentration stage on the global recovery and concentrate grade. The uncertainties are represented by normal, uniform and triangular probability distribution functions (PDFs). The case studies include the uncertainty in the recovery of each stage separately and simultaneously across all of the stages with different standard deviation levels. A total of 2880 cases were studied, which corresponded with twelve circuits, three distribution functions and 84 different combinations with standard deviations in the stage recoveries. For each case, 2000 simulations were performed, with an overall simulation total of 5.76 million. Among the conclusions obtained in this work are the following: 1) The shape of the distribution function in the output variables is dependent on the input distribution function, the concentration circuit and the uncertainty level; 2) when the recovery of a single stage is represented by a PDF, the other stage recoveries are assigned a deterministic value then the type of the PDF obtained for the global recovery is similar to the input distribution; 3) when considering uncertainty in several stages simultaneously, the resulting PDF type usually is not the same PDF type observed for the input variables; and 4) the circuit structure affects more than the stage recoveries in the analysis of the global recovery and concentrate grade.