GREG LANE1, SIMON HILLE2, JOE PEASE3, & MATT PYLE4
1Ausenco, 2Newmont Goldcorp, 3Mineralis, 4Ausenco
SAG Conference Vancouver, Canada September 22 – 26, 2019
ABSTRACT
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.
Keywords
Crushing, grinding, SAG mill, ore sorting, Vertimill, MillSlicerTM, separating tank
ACKNOWLDEGEMENTS
The authors would like to acknowledge the support of the parent companies: Ausenco, Newmont Goldcorp, and Mineralis for permission to discuss this important topic with the broader mineral processing network. We would also like to make special mention of CEEC and CMIC for their support and vision on energy and water efficiency matters.