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Rowena Duckworth
Viking has delivered a major metallurgical milestone at its Linka tungsten project in Nevada, USA, producing a top-tier scheelite concentrate using just simple gravity separation – essentially using the natural weight of tungsten-bearing minerals to separate them from waste rock.
As no expensive chemical reagents or complex processing infrastructure are needed, this also means costs can be kept way down.
Starting from a feed grade of 1.2 per cent tungsten trioxide, Viking’s test work achieved an extraordinary upgrade to a concentrate grading 63.6 per cent tungsten trioxide, coupled with a 42.4 per cent overall recovery.
With a more than 53-fold improvement in a single pass, concentrate grades sit within the top tier of global scheelite products and are firmly in premium offtake territory.
‘This demonstrates we can produce a high-value, offtake-grade product without the need for the complex or expensive chemical processing.’
Viking Mines managing director and chief executive officer Julian Woodcock
When blended with the middlings stream, recoveries appear to climb even further while still delivering a highly saleable 56.4 per cent tungsten trioxide concentrate.
In the world of critical minerals processing, the simpler the flowsheet, the better. Complex processing plants require more capital to build, more time to permit and construct and carry more technical risk.
A gravity-led circuit is the opposite. It’s modular, relatively low-cost and fast to build. Viking has flagged a ‘Rapid-Start’ development model as a key ambition, and these test work results suggest the model is very much within reach.
Linka hosts high-grade scheelite mineralisation within a classic skarn system in the Spencer Hot Springs Mining District, 7 kilometres south of Highway 50 in Nevada. It forms part of Viking’s wider Nevada tungsten grounds acquired late last year. Across four historic sites, the broader Nevada portfolio has previously churned out 123,000 tonnes of ore grading 0.54 per cent tungsten trioxide, underscoring the district’s proven tungsten pedigree.
Viking Mines managing director and chief executive officer Julian Woodcock said: By focusing on a gravity-led flowsheet, we are drastically lowering our potential capital costs and putting Viking on a much faster track to construction and cash flow in the heart of Nevada.”
Notably, the company has also completed initial flotation test work on the material left over after gravity separation – the so-called ‘gravity tails’ – and recovered a meaningful additional portion of the contained tungsten.
Combined gravity and flotation recovery is already tracking strongly after a first pass, with further optimisation work underway. Cleaner flotation test work has now begun to generate a saleable concentrate from the flotation stage, complementing the gravity product.
The timing of these results is hard to fault. Global tungsten prices, as measured by the Ammonium Paratungstate (APT) benchmark, recently reached all-time highs, and supply remains in structural deficit; a situation compounded by ongoing conflicts in the Middle East and Ukraine, disrupting established supply chains.
The US Department of Defence has flagged tungsten as a strategic priority material, and domestic producers capable of supplying ‘NATO-grade’ product are increasingly valued. Linka sits squarely in that conversation.
With a conceptual processing study already underway by specialist firm Mineral Technologies, maiden drilling permitting in progress, and a steady pipeline of further test work results to come, Viking appears to be building momentum at precisely the right moment in the tungsten cycle.
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