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American West has a winner on its hands after ore sorting test work on mineralisation from the Storm project generated a 53.9% copper direct shipping ore product. The DSO material has no impurities and was produced using a conventional full-scale sorter, meaning that a potential development is likely to have low costs, a small footprint and environmentally friendly processing.
This was possible thanks to the straightforward nature of the copper mineralogy and host rocks of American West Metals’ (ASX:AW1) Storm Copper project on Somerset Island, Nunavut.
“The work has produced a commercial grade DSO product through an uncomplicated and low-cost process that is game changing for this project and plays to our strategy of developing very low footprint operations,” managing director Dave O’Neill said.
“The process of generating DSO at Storm is amazingly simple and highlights our company’s focus on generating ESG sensitive mining solutions. Storm copper now stands out as one of the very few, and highest-grade DSO copper projects globally.
American West has planned an extensive drill program that will focus on resource definition and expansion of the known high-grade copper mineralisation through testing of high priority electromagnetic targets.
Historical drilling at Storm has intersected structurally controlled, high-grade copper including stand-out intercepts such as 110m grading 2.45% copper from surface and 56.3m at 3.07% copper from 12.2m.
Copper ore sorting test
The composite sample selected from a 4m interval within hole STOR1601D is considered to be representative of the high-grade copper mineralisation discovered at the Storm Project to date.
This was crushed to a size fraction of 10mm-25mm – the optimal size for the full-scale ore sorting equipment before being washed prior to processing.
A combination of X-Ray transmission and 3D laser sensors were used in the sorting algorithms given the expected density contrasts between the ore and waste.
The ore sorter produced three products, a very high-density material that qualifies as DSO, a high-density material and a low-density material.
The DSO material is likely comprised of pure chalcocite – an important copper mineral – and a small fraction of waste material.
Despite the simplicity of its production, its optimised grade is superior to many other DSO copper products globally.
Meanwhile, the intermediate high-density product likely represents a portion of the sampled interval where there is fine-grained chalcocite that wasn’t liberated with crushing of the 10-25mm fraction.
Optimisation of the sorting algorithm to recover the remaining fine grained chalcocite, followed by further crushing is expected to successfully upgrade this material to DSO grades through simple conventional physical separation.
Any fines lost in the original crushing circuit will likely be reprocessed with the intermediate material.
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