ORE SORTING
more accurate sort than a combined XRT and Laser-based system situated on conveyor belt . In fact , we had one study with a Canadian junior miner that pitted the two systems against each other and showed 5 % higher recoveries for our solution over the conveyor-based alternative .”
Gold projects – whether sulphide-associated , quartz-associated or both – continue to represent a large proportion of test work the company processes , according to Rutledge , who said three projects were set to move from contract agreement to installations this year .
And the companies TOMRA is working with are looking at installing these units at various points of the flowsheet .
“ We have three main areas we tend to see sorting implementation ,” Rutledge said . “ One brownfield project this year is going to process waste stockpiles to both upgrade those stockpiles and create a pure waste stream that could provide value as something like an aggregate .
“ We have also seen sorters installed on the pebble mill rejects , which is similar to the setup at Coeur ’ s Kensington project in Alaska .
“ Then , finally , if they are implementing it directly into the flowsheet – for greenfield projects – they are looking at installing units after secondary crushing .”
Outside of gold , Rutledge was keen to talk up TOMRA ’ s solutions for the battery minerals space and , in particular , the lithium sector .
“ We have so many projects in lithium and a clear sorting task that we can solve with ease ,” she said . “ A lot of hard-rock projects out there have issues removing basalt with dense medium separation circuits , and that is a very easy sort for us .”
Removing basalt reduces contamination issues down the processing line , according to Rutledge , who has plans to move to Perth , Australia , to help make the most of this hard-rock lithium demand .
This is the case at one of the company ’ s project references at Galaxy Resources ’ Mt Cattlin hard-rock lithium mine in Western Australia , where TOMRA has provided two PRO Secondary Laser sorters to treat 1.2 Mt of ore Galaxy previously stockpiled due to basalt contamination .
Rutledge said the company ’ s sensor-based sorter offering for the lithium space goes beyond just the Laser option .
“ What is different is we can potentially use all of the technologies differently for this task in lithium ,” she said . “ We use Colour , Laser , Near Infrared ( NIR ) or XRT . Some of the technologies we have sold use different technologies for different stages of the process . They will use colour and XRT , or Laser or NIR in series or along the process , which is kind of unique .”
This type of sensor fusion has been witnessed by TOMRA across the sector – and not just with its own solutions .
Rutledge noted that several customers are using the company ’ s sensor-based products for sorting purposes and prompt gamma neutron activation analysis ( PGNAA ) -based sensors from other vendors in the same operation for verification purposes .
“ In those cases , they generally sort with our units and use the PGNAA to analyse the product stream in place of something like a grab sample ,” she explained .
‘ Test before you buy ’
Steinert ’ s Business Development Manager for Mining , Lütke von Ketelhodt , sees the rationale in combining sensor solutions at mine sites , mostly tied to bulk ore sorting at the front end and particle sorting closer to the recovery circuit at large mine sites .
In such a setup , this would see bulk sorters separating high- and low-grade streams , and the particle sorters treating low-grade streams to remove the final waste fraction and a scavenged product fraction .
In Steinert ’ s case , however , the company can boast about a particle sorting platform that has multiple sensors installed on it . Its KSS units can be equipped with XRT , X-ray Fluorescence ( XRF ), NIR , Laser and Colour sensors , opening the door to use across a wide range of commodities .
The combination of two of these sensors – XRT and Laser – was proven in recent test work with ASX-listed Future Metals , which demonstrated 96.7 % recovery of high-grade ore and rejection of low-grade material and waste at its Panton platinum group metal ( PGM ) project in Western Australia using the KSS XT CLI Ore Sorter . This recovery rate , Panton says , increased the PGM grade of the potential mill feed by 10.7 % and reduced the throughput volume by 12.7 %.
With the recent addition of new sorting lines for mining and waste recycling at its new test and development centre in Pulheim , Germany – all aimed at better achieving the company ’ s aspiration of “ test before you buy ” – more companies like Future Metals are viewing the
In addition to regional test centres in Pulheim , Germany ; Perth , Australia ; Kentucky , USA ; and Belo Horizonte , Brazil ; Steinert has local testing plants all over the globe
potential benefits of sorting via Steinert ’ s solutions .
“ In addition to the Pulheim facility , Steinert also operates regional test centres in Perth , Australia ; Walton , Kentucky , USA ; and Belo Horizonte , Brazil ,” von Ketelhodt said . “ The Steinert application engineers operating these test facilities collaborate regularly to exchange experiences on best sensor settings , or sensor combinations for different ore sorting applications . This collaborative process has enabled Steinert to process more samples with consistent high-quality results .”
And many of those samples are coming from the gold space , according to von Ketelhodt .
The proposition for ore sorting – removing waste to provide an upgraded mill-feed product , while saving energy , water and costs associated with the downstream process – remains the same for yellow metal miners , but the complex and costly logistics associated with many brownfield gold operations means applying these solutions can have above-average impacts .
“ We have some clients looking to re-start operations at old mines ,” von Ketelhodt said . “ They usually process the ore at a modern mill and process facility , which is some distance away from the mine . Ore sorting at the mine site reduces the haulage mass considerably , which is a huge cost saver for the operation .”
Obviously reducing the amount of material hauled from the mine to the process plant has a tangible impact on not only cost , but also the energy intensity associated with processing that ore . Such considerations are becoming more prominent in the conversations Steinert is having with the mining community , according to von Ketelhodt .
“ Indeed , climate change goals , such as reducing energy consumption and reducing the carbon footprint , are very important topics in the mining industry , and Steinert is gaining more attention for the way its ore sorters can
38 International Mining | MARCH 2023