Millennium Minerals has appointed engineering firm Ausenco to complete a feasibility study on an alternate processing option as part of a sulphide ore expansion study at the Nullagine gold project in Western Australia.
The study is aimed at unlocking the full economic potential at Nullagine and identifying pathways to process the large sulphide mineral resource inventory. It was largely completed last quarter.
Initially, the study was based on a preferred plant and configuration comprising an integrated CIL and flotation circuit.
The expansion pathway is expected to involve the integration of a flotation circuit capable of treating sulphide ore with an existing 2Mtpa CIL plant.
According to the study, the capital expenditure required to fund the plant modifications would be around $40m-$46m.
Millennium chief executive Peter Cash said: “The ‘Sulphide Ore Expansion Study’, which underpins our corporate objective of becoming a 100,000oz-a-year producer by unlocking the existing large sulphide mineral resource inventory at Nullagine, is now in its final and most important stages.
“The identification of this new processing option could transform the economics of the expansion project, dramatically reducing both capital and operating costs and resulting in a major reassessment of our reserve inventory.
The company reported that processing costs for the free-milling fresh ore were estimated to be A$19 per tonne, while processing costs for the sulphide ore were estimated to be around A$27.50 per tonne.
Working with MineScope Services, the company has identified an alternative processing configuration, which could result in reducing both capital and operating costs compared with the integrated CIL and flotation circuit, while also delivering several benefits to its expansion plans.