Terrain Minerals has cleared a major technical hurdle at its Lightning gold project in Western Australia, with metallurgical testwork confirming high gold recoveries of up to 93.7 per cent using a simple, conventional processing flowsheet.
The results indicate the gold is free-milling in nature and can be treated using a standard WA gold plant operation, opening the door to potential toll-treatment opportunities for the company, which is within trucking distance of several Murchison mills.
Toll treating in the Murchison has become an increasingly popular pathway to early cash flow rather than tinning up for an entirely new facility, with companies such as the $900 million market-capped New Murchison Gold using nearby processing infrastructure to accelerate production at current favourable gold prices.
Terrain says its three composite samples, with head grades of 2.55 grams per tonne (g/t) gold, 0.93g/t gold and 1.47g/t gold, returned overall gold recoveries of 87.0 per cent, 92.1 per cent and 93.7 per cent, respectively.
Crucially, the recoveries were achieved at a conventional grind size of 75 microns, meaning expensive ultra-fine grinding is not required.
The testwork also showed a healthy proportion of the gold can be recovered through a simple gravity circuit before leaching, with gravity-only recoveries of 32.6 per cent, 30.6 per cent and a notable 50.8 per cent for the three composites. Additionally, under optimised conditions, recoveries reached 95.3 per cent after 24 hours of leaching.
Terrain Minerals executive director Justin Virgin said: "The testwork shows that Lightning gold can be treated through a conventional gold processing plant, with recoveries in the high eighties to low nineties, a straightforward grind size and a meaningful proportion of the gold recoverable by gravity. Importantly, we have seen no indication of refractory behaviour."
The Lightning gold project forms part of Terrain’s wholly-owned Smokebush project, 350 kilometres north of Perth in the prolific Murchison terrain.
Just three months ago, Terrain delivered a maiden starter resource for the prospect, clocking in at 677,000 tonnes of material at a promising 2.5g/t gold for 54,000 ounces, plus a handy silver credit. The project sits on a granted mining lease, another tick in the box for potential rapid development.
With the metallurgy box now firmly ticked and fresh cash in the bank from a recent capital raising of up to $2.5 million, cornerstoned by Gandel Metals, Terrain is gearing up to unleash a 10,000m drilling blitz at Lightning. Better still, the company now knows any new ounces it discovers should slot neatly into a conventional WA processing circuit – a valuable advantage that could one day open the door to fast-tracked toll treatment and early cash flow.
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By Andrew Todd
