Viking maps out US tungsten processing pathway

Viking Mines has banged a significant technical peg in the ground at its Linka tungsten project in Nevada, USA, with an independent concept study confirming a clear and conventional processing pathway just as a drill rig arrives on site to spin the rods at the historic operation for the first time in almost half-a-century.

The study, completed by Mineral Technologies, outlines a process for a 300,000-tonne-per-annum (tpa) plant based on established tungsten processing practices.

The flowsheet uses scheelite’s high specific gravity to make gravity concentration the natural recovery method, and includes staged crushing, high-pressure grinding, closed-circuit milling, multi-stage gravity concentration using spirals and tables and a flotation stage to recover finer material.

The company says the plant design centres on a modular approach, with components made offsite to minimise on-site construction time and risk. The study also highlights the plant’s flexibility, noting that while it has an upper capacity of 300,000 tpa it can run at lower throughputs of 100,000 or 200,000 tpa simply by reducing operating hours.

‘Our near-term focus remains testing the primary tungsten system with the drill bit.’

Mineral Technologies has estimated a build time of about 15 months, comprising 12 months for procurement and fabrication and a further three months for on-site assembly.

Notably, the processing study was based on a conservative metallurgical recovery of 60 per cent of scheelite, the tungsten-bearing mineral, into a 50 per cent tungsten trioxide concentrate. That figure sits well below the company’s own recent metallurgical test work, which clocked a much bigger 76 per cent recovery to produce a high-quality 56.9 per cent tungsten trioxide concentrate.

Importantly, Viking’s reverse circulation drilling program marks a further significant step in its goal to define a maiden mineral resource at the past-producing mine. With earthworks and drill pad preparation already underway, drilling is expected to kick off this week.

The company’s maiden campaign is looking to test scheelite-bearing skarn mineralisation across three specific target areas, extending shallow, near-mine high-grade mineralisation and testing for down-dip extensions at the old Linka workings.

The program will also probe for extensions to the south-west under shallow cover and conduct first-pass regional drilling along a broader, seven-kilometre mapped intrusive contact, of which only 10 per cent has been properly tested.

Viking has not disclosed indicative capital or operating costs from the study, consistent with ASX guidelines, as a mineral resource or ore reserve has not yet been inked for the project. The maiden drilling campaign represents the critical first step toward establishing the resource.

The timing of the program also looks savvy, with European tungsten prices recently hitting multi-year highs of US$3265 (A$4694) per metric tonne unit (MTU) for 88.5 per cent ammonium paratungstate. One MTU equates to 10 kilograms.

Viking Mines managing director and chief executive officer Julian Woodcock said: “This study gives us an independent, credible engineering view that Linka mineralisation can be processed through a conventional, well-understood flowsheet – and importantly, through a modular plant designed to keep site works and upfront capital efficient.”

Beyond the flagship Linka operations, the company maintains an active footprint across several other asset holdings in Nevada. Viking’s regional land claims include the Alpine, Long, Ragged Top, Terrell and Victory tungsten projects, which are held under various unpatented mineral claim agreements.

The company says it’s actively gathering and evaluating historical exploration data across these peripheral claim blocks to plan future field campaigns.

It seems Viking has put its ducks in a row in the best possible way at its Linka project. With the drill rods now ready to spin to check what lies beneath, the company now has a solid technical plan for how to process it.

By running the engineering and resource drilling workstreams together, the company is positioning itself to make quick strides once the drill results start rolling in.

For Viking, having a clear processing pathway mapped out this early in the game is a solid piece of de-risking that could pay dividends down the track.

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