Lake Lefroy, Western Australia
Background
The St Ives lease area is situated within the Kambalda-St Ives corridor in the south-central portion of the Archean Norseman-Wiluna Greenstone Belt within the Yilgarn Craton, Western Australia. Since the mid-1980’s, more than 10.5 million ounces of gold has been produced from this area.
A scoping study was commissioned by Goldfields St Ives Pty Ltd, to assess the viability of alternative mining methodologies compared to conventional truck and shovel open pit methods, in order to exploit a gold deposit within the Lefroy Palaeochannel. The use of a Bucket Wheel Excavator (BWE) had been selected as a favoured methodology and this highlighted the need to consider the geotechnical setting of the palaeochannel, along with other factors, to appropriately evaluate the proposed mining methodology.
Scope
Following a desktop study, CMW personnel were mobilised to the mine site to undertake HQ3 coring and SPT testing at various locations overlying the palaeochannel.
In-situ shear strength testing was performed on the recovered core before samples were taken for laboratory testing to determine the strength, grading and plasticity characteristics of the differing strata.
Findings/Challenges
Following a desktop study, CMW personnel were mobilised to the mine site to undertake HQ3 coring and SPT testing at various locations overlying the palaeochannel.
In-situ shear strength testing was performed on the recovered core before samples were taken for laboratory testing to determine the strength, grading and plasticity characteristics of the differing strata.