Preliminary ore sorting test work on material from Nova Minerals’ (ASX: NVA) Korbel Main deposit has generated “exceptional” results for the company.
Sorting was undertaken on 10kg of ore from the Korbel Main deposit within Nova’s flagship Estelle project in Alaska.
Bulk ore sorting alone resulted upgrading Korbel Main’s 0.25 grams per tonne gold material to 0.31g/t gold grade with a reject waste grade of 0.06g/t gold.
Combined bulk and particle ore sorting managed to deliver a high-grade feed stream from mined material – upgrading the feed to 6g/t gold.
Nova chief executive officer Christopher Gerteisen said the Korbel Main deposit continued to “amaze” the company.
“It is shaping up to be world-class in terms of the resource endowment, but all in other key technical aspects, such as being at surface, its exceptional metallurgical properties, including gold recovery.”
“These results have now confirmed that ore sorting presents a real and future prospect to gain higher operational efficiencies as we progress through our economic assessment work.”
Mr Gerteisen added minimising mine dilution and mineral loss was key as the company progresses its preliminary economic assessment.
“Now, with ore sorting, we have the potential to add further value as material processing through bulk and particle ore sorting can be diverted into streams of high grade through a carbon-in-leach circuit and the remaining material diverted to the heap leach, with minimal material lost to waste,” he explained.
Benefits of ore sorting
According to Nova, ore sorting is increasingly being used in commercial mined including manganese, iron ore, nickel, phosphate, uranium, coal and gold.
In Nova’s case, the process involves separating the gold from waste via either particle or bulk sorters – or both.
Nova noted this method is a mature and proven technology and can generate high recoveries, and remove variability in plant feed.
Including this step can also create additional value by increasing life of mine, minimising mining, haul, and energy costs, while also reducing water consumption and tailing requirements.
It has the added advantage of boosting reliable ore availability and production, as well as generating a saleable coarse waste product.
The initial ore sorting test work will continue until early January. Particle sorting test work on a larger sample is planned to begin in the March quarter next year with results anticipated early in the June period.
Additionally, an advanced stage of bulk sorting test work is beginning with data also expected early in the June quarter.
Korbel Main has a current resource of 290Mt at 0.35g/t gold for 3.275Moz. An updated resource is planned to be released early next year.
Nova recently completed a $21 million placement to fast-track Estelle with proceeds to fund ongoing drilling of priority targets, as well as advancing metallurgical, economic and environmental work.