B PUTLAND, I LOVATT, A CERVELLIN AND D SCHWANN
14thAusIMM Mill Operators’ Conference, 29-31 August 2018, Brisbane, Australia
The Mount Carlton project in Queensland's North East sits on a high-sulphidation epithermal style deposit
rich in gold, copper and silver.
Mt Carlton is an open pit mining operation with ore processed using a primary crusher, single stage SAG mill
and flotation to produce a concentrate for sale. Orway Mineral Consultants (OMC) was involved in the
original design of the comminution circuit and the project was commissioned in late 2012, with first
concentrate shipped in March 2013. When Evolution sought to optimise the project in 2015, OMC was
invited to assist by undertaking a circuit review to identify opportunities for the optimisation.
During 2016, the Mt Carlton site team implemented the optimisation strategies developed in conjunction with
OMC. These included reconfiguring the SAG mill discharge arrangement, reducing the average ball diameter
and allowing the mill to operate at higher speed and under more autogenous conditions. Cyclone operation
was changed to constant pressure and the vortex finder size was decreased.
The combined strategies improved energy efficiency and allowed higher SAG mill power utilisation. The
additional power has been used to increase throughput by 2.4 per cent while achieving a 27μm reduction in
product size (P80) to gain downstream recovery improvements. The reduction in grind size has been
achieved with only 6.8 per cent increase in specific energy consumption because of a 6.5 per cent increase
in grinding efficiency. The circuit product size is also notably more consistent due to the improvements made
to the cyclones, providing benefit to the downstream flotation circuit. A significant decrease in ball
consumption was also gained, saving hundreds of thousands of dollars a year in operating cost.
This paper discusses the circuit design, start up, and details the changes made during the optimisation
and why these were successful.
B PUTLAND (1), I LOVATT (2), A CERVELLIN (3) AND D SCHWANN (4)
(3) MAusIMM, Senior Metallurgist, Evolution Mining Limited, Townsville QLD 4810. Email:
CEEC acknowledges and thanks The Australian Institute of Mining and Metallurgy for organising the 14thAusIMM Mill Operators’ Conference (MillOps 2018).
Abstracts can be found at the MillOps 2018 website.