A technical paper has detailed a collaborative engineering project between SMC Corporation Australia New Zealand and Evolution Mining’s Northparkes Operations aimed at improving flotation circuit stability and slurry level control at the New South Wales copper-gold mine.
According to the paper, Northparkes replaced traditional mechanical positioners on flotation cell dart valves with SMC IN-777 air servo cylinders and reported an immediate 56% reduction in flotation cell level variance. The paper also reports a 1.21% increase in copper recovery across the circuit, which it links to the improved stability and subsequent process optimisation.
Northparkes, in the Central West of New South Wales, undertook the work following a flotation circuit expansion as it sought to further optimise circuit performance. The paper notes that slurry torsion on internal dart valves led to frequent calibration and maintenance requirements for mechanical feedback linkages, contributing to underflow control valve inconsistency and slurry level deviations of up to ±50 mm.
Andrew McCluskey, Head of Sales for Western Australia at SMC Corporation, said Northparkes implemented a non-contact positioning system “to mitigate these mechanical variances and streamline maintenance”.
The design described in the paper includes a heavy-duty floating joint installed between the piston rod and adapter box to allow the dart stem to rotate under slurry torsion without transferring stress to the cylinder mechanism, and the IN-777 air servo cylinder, which uses an integrated magnetic position feedback sensor instead of mechanical linkages. The system is described as IP67-rated and intended for mineral processing environments.
The paper reports that valve full-stroke travel time was reduced from around 30 seconds to 4.5 seconds, enabling faster response to upstream process surges. It also reports that slurry level control tolerance improved from deviations of up to ±50 mm to consistent control down to ±10 mm and ±5 mm.
With more stable level control in place, the paper says Northparkes activated ESTIMATA, described as a cloud-based real-time process optimiser that calculates circuit mass balances and sends froth velocity setpoints to PLCs every five minutes. The reported recovery improvement was based on on/off plant trials conducted over 15 weeks.
SMC also said it will demonstrate the IN-777 system at the Future of Mining exhibition in Perth on 16–17 June.
