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Tailing Thickener Operability and Control Improvements at Prominent Hill


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Author M Weidenbach and J Lombardi


OZ Minerals’ Prominent Hill copper-gold concentrator is located 650 km north-east of Adelaide, 130 km north-east of BHP Billiton’s Olympic Dam operation and 130 km south-east of the regional township of Coober Pedy, in the Gawler Craton region of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a 10 Mt/a ore throughput capacity, operating well over the design rate of 8 Mt/a. Increased throughput rates have seen a decreased water recovery from the tailing thickener due to operating above design. Subsequently, greater pressure was placed on the site water balance and bore field off-take rates due to increased evaporation losses from greater volumes of water reporting to the tailing storage facility. This resulted in a trade-off between water availability and milling rates as part of the operating strategy.

Two projects were implemented to increase the tailing
thickener underflow density, thus improving water recovery directly back into
the operating plant, reducing water losses via evaporation and decreasing the
reliance on the bore field system operating at maximum rates to maintain mill
throughput. The two projects were:

  • tailing thickener feedwell redesign

  • implementation of the Manta Cube control system.

This paper discusses the background, implementation and benefits attained from these two key projects. Combined they have allowed a two to three per cent increase in tailing thickener underflow density to be consistently achieved, which has allowed greater water recovery. As a result, the processing plant has been able to operate at higher throughput rates when required, with greater water availability in the process plant recirculating system and a reduction in occurrences of the plant being ‘slowed down’ due to water supply shortfalls. Both projects have also delivered a significant reduction in flocculant usage.

Weidenbach, M and Lombardi, J, 2012. Tailing
thickener operability and control improvements at Prominent Hill, in
Proceedings 11th AusIMM Mill Operators’ Conference, pp 137-142 (The
Australasian Institute of Mining and Metallurgy: Melbourne).