STEFAN NADOLSKI1, RUSS HAYCOCK2, KEVIN LI2, SANTIAGO SEILER1, & AMIT KUMAR1
A comprehensive energy study was carried out for the Red Chris mill, which processes copper-gold ore at a rate of 30,000 tonnes per day (t/d) and is located in Northern British Columbia. The study focused on identifying opportunities for energy conservation in the semi-autogenous grinding (SAG)-ball mill and regrind circuits. Mill surveys were carried out to calibrate mill models, such as those in JKSimMet, for simulation of alternative operating scenarios. Energy benchmarking methods were used for all circuits, including a Vertimill regrind circuit, to evaluate nominal energy performance and compare circuit configurations.
For the SAG and ball mill circuits, considerable flexibility in the material handling system allowed alternative flowsheets to be assessed. Evaluated energy conservation measures included implementation of SAG mill charge monitoring technologies to allow for mill speed reduction, diversion of pebble crusher product to the ball mill circuit, sensor-based sorting of pebble crusher feed, and modification of media sizes.
The regrinding circuit consists of a grate-discharge ball mill and a Vertimill, which is operated with a separating tank. Circuit surveys and energy benchmarking through use of an Eliason laboratory stirred mill test showed that the Vertimill separating tank was ineffective as a size classifier. Overall, the paper presents a summary of energy benchmarking efforts and evaluation of identified energy conservation opportunities.
Crushing, grinding, SAG mill, ore sorting, Vertimill, MillSlicerTM, separating tank