In August 2018 the first full-scale pneumatically assisted fluidised bed flotation cells for the recovery of coarse composited gold and copper were commissioned at Newcrest’s Cadia Valley operation in New South Wales. The primary objective of the installation is to recover coarse value-bearing composites that are currently lost to conventional flotation tailings, without additional power input for particle size reduction to improve mineral liberation.
The Eriez HydroFloat™ separator is an aerated fluidised-bed (or teeter-bed) separator that has been demonstrated to increase the recovery of coarse, poorly liberated particles, compared to conventional flotation technology, by combining flotation fundamentals with hydraulically assisted separation. The technology was invented by Eriez in 1997.
At Cadia, composite particles are the principal carrier of gold and copper in the rougher tailings making up 50–60 per cent of the contained value in 2–5 per cent of the mass. Over 50 per cent of the composite particles in rougher scavenger tailings are in the lowest sulphide exposure range <10 per cent, where recovery via the existing conventional flotation circuit is poorest at only 30 per cent. this poor recovery of composite particles with low surface exposure presented a significant opportunity for the application of hydrofloat™ technology in a scavenging capacity.>
The Cadia Coarse Ore Flotation Circuit is a novel application of aerated teeter-bed technology in sulphide flotation and presented many challenges during the commissioning and subsequent optimisation phases that needed to be solved to achieve successful delivery of the project. This paper gives an overview of the commissioning and ramp up journey, major operational challenges and solutions, high-level operational strategy and some analysis of the circuit performance to date.