Thank you for your input on ore sorting and the limitations of gravity-based methods in AW1's location. I agree that there are challenges when using wet gravity separation, especially in colder climates where maintaining water in liquid form for part of the year can be an issue. However, recirculation and heating of the water within the jigging circuit should address the issue.
Regarding ore sorting, it's important to note that, while visual sorting technologies like basalt rejection work well in certain contexts (e.g., pegmatite lithium ore), AW1’s copper mineralisation presents different challenges or opportunities. The copper sulphide minerals—chalcopyrite, bornite, and chalcocite—have significantly higher specific gravities compared to the surrounding dolomitic gangue. This physical difference will be leveraged to achieve a separation through methods like Steinert’s or Tomra's dry sorting technology, which will predominately use X-ray transmission for ore classification.
In fact, the original trial on drill core samples at Storm achieved some promising results, where ore sorting led to a high mass yield with excellent copper recovery. For instance, the high-density fraction, which contained 53.9% Cu, represented just 10.2% of the feed mass and achieved an 82% copper recovery for the Coarse Fraction. More recent Met testwork is indicating Chinook deposit achieving a 6.5% mass yield & Cyclone deposit having 5.5% mass yield for producing an 18% Cu conc grade DSO product. With DSO copper grade influenced by the degree of mineral liberation (see table below).
This suggests that the 1.5% Cu ore can be effectively upgraded using physical properties such as specific gravity or density, without the need for complex and costly methods like flotation.
For upgrading of finer particles, Dense Media Separation (DMS or Jigging) will play a key role rather than ore sorting. It’s a robust, cost-effective process that works well for copper sulphide ores, particularly when the mineral’s density differs substantially from the waste rock. While DMS might not be as selective as ore sorting, it has the advantage of being adaptable to a wide range of ore types and sizes. Additionally, the lower capital cost compared to high-tech ore sorting systems could make it an attractive option for the overall mineral processing flowsheet in AW1’s remote location, where minimizing upfront costs is crucial.
I believe AW1 is positioned to benefit from Ore Sorting & Dense Media Separation technologies to produce a high-quality product for the copper smelting market.
While there are no ‘free lunches’ in ore sorting, the combination of these techniques offers a viable, sustainable approach for Storm Copper's early-stage development.
Note: Mineral liberation classes (shown below) - assume the black section of the particle is the copper bearing mineralisation & the white section is the dolomite mineral. Hence, depending upon how particles fracture (Cu - dolomite interface) will determine the ultimate copper grade of the DSO.
