COMMINUTION
Complementary comminution
The need to consider emissions and embed sustainability into the mineral processing mix has caused a flowsheet rethink , Dan Gleeson reports
The scope of supply at the Agnew gold operation included a Sandvik reciprocating plate feeder , grizzly screen , jaw crusher and two cone crushers , as well as a Schenck Process doubledeck banana screen fitted with Screenex screening media
In a recent interview with IM , Weir CEO Jon Stanton identified a major shift in the mining supplier-client relationship ; a shift that goes some way to understanding why the ‘ new technologies ’ being spoken about for years , if not decades , are finally taking hold .
“ Mining CEOs have openly admitted that mining today has the suppliers … it deserves as there has sometimes been a degree of arrogance based on ‘ we know what we are doing , just give us the equipment ’,” he said . “ It has been quite a site level , procurement and maintenance only , transaction-based relationship .”
This is rapidly shifting to a more strategic level of relationship and a recognition that the individual mining houses can ’ t do everything on their own . “ It needs to be more of a collaborative effort ,” Stanton said . “ And we , as suppliers , I think need to also be bolder and braver in terms of challenging the mining houses to ask the right questions to deliver their overall objectives and to some extent to think outside the box .
“ That dynamic has really changed in the past two to three years – today it ’ s about how we work together better , which includes the site-level conversations but also CEO to CEO and C-suite to C-suite as well as regional leadership teams – a true collaboration means being connected at all levels . And this is happening already .”
Chalk and cheese
Such collaboration has been on show in Western Australia where all the way back in 2020 Sandvik Rock Processing Solutions and Gold Fields started early design work on an ambitious project to build an entirely new crushing and screening circuit at the Agnew gold mine .
The mine is best known for its underground operations , primarily targeting the Agnew and Lawler gold deposits . The ore is extracted using a combination of underground and surface mining and is then processed on-site .
Around 2018 , with the mine expanding into a third underground source , there was a need to increase plant throughput . The 21-year-old tertiary crushing circuit , which was suffering from poor reliability , was unable to meet the demand . “ It was working to its limits , and if you compared it to other Gold Fields sites , it was not to the standard that would be accepted elsewhere ,” Gold Fields Metallurgy Manager , Reg Radford , said . “ It didn ’ t meet our criterion for a wellorganised , safe , professional gold processing operation .
“ The equipment was old , and there was little or no spare parts availability . From a
metallurgical perspective , it was being pushed to its limits to deliver the tonnage required . At best it was giving us an 8-10 mm output , which was putting pressure on the downstream grinding circuit .”
The age and complexity of the existing plant also meant access for operation and maintenance was difficult , presenting potential safety concerns .
The existing crushers were reaching end-of-life and , rather than just replacing them , it was decided to build an entirely new crushing and screening circuit .
To do this , and address various other concerns regarding the existing plant , a comprehensive upgrade project , known as the Agnew Stage 1 Upgrade , was conceived . The initiative examined bespoke and modular designs that could replace the existing plant . The project aimed to improve site water drainage and dust management ( by installing a fine ore bin ) while minimising disruptions during construction and commissioning .
Gold Fields has enjoyed a long-standing relationship with Sandvik , as the company has Sandvik crushers installed at both its St Ives and Granny Smith operations . After considering a
10 International Mining | MARCH 2025