As part of the Cadia East Project, the Low Grade Concentrator was upgraded to enhance gold recovery and processes to maintain a throughput of 20 Mt/y of ore.
This project is the deepest panel cave in the world and Australia's largest underground mine with an expected mine life of more than 30 years.
Ausenco designed a new comminution circuit for the existing concentrator to allow for the treatment of much harder ore. We created an innovative circuit incorporating High Pressure Grinding Rolls (HPGR) technology prior to the Semi-Autogenous Grinding (SAG) mill to improve efficiency and increase throughput of the concentrator.
This design not only reduced carbon emissions, but increased the energy efficiency of the comminution circuit by around 25%.
This upgrade consisted of four stages:
- Stage 1 - 16MW ball mill and 40m dia. tailings thickener
- Stage 2 - Secondary crushing and screening
- Stage 3 - Flotation
- Stage 4 - High pressure grinding roll and concentrate pumping
Project challenges
- Ore competency and impact on novel comminution circuit, to be addressed by staged implementation and flexible circuit design
- Delivering further gold recovery uplift through targeted gravity gold concentration, to be addressed by additional test work
- Variability of fluorine and uncertainty of levels reporting to final concentrate, to be addressed by additional regrind facilities.
Project achievements
- Awarded Contractor of the Year Award for this upgrade from the 2012 Annual Australian Mining Prospect Awards.