Encouraged by a surging gold price, GreenTech Metals has identified significant gold associated with the copper in a review of more than 50,000 historical samples from its Whundo copper-zinc project in Western Australia’s West Pilbara region.
The review of more than 1195 holes uncovered a suite of high-grade gold values and some long intercepts, which could form the basis for a new economic opportunity at Whundo.
A best intercept of 1 metre assayed 64.7 grams per tonne (g/t) gold from 47m in the Whundo zone at the south end of a 2 kilometre-long mineralised trend.
Three other holes in the mineralised zone each produced 1m intercepts assaying 12.75g/t gold from 23m, 4.8g/t gold from 25m and 5.42g/t gold from 4m.
In the historic Ayshia workings at the northern end of the trend and 2km north of Whundo, a drill hole intercepted 10m at 1.8g/t gold, 3.44 per cent copper and 3.5 per cent zinc from 35m. The hit included 3m at 3.3g/t gold, 3.6 per cent copper and 1 per cent zinc from 41m.
Ayshia’s next best intercept delivered 4.3m assaying 1.8g/t gold, 1.82 per cent copper and 14.1 per cent zinc from 39.6m, including 1.7m going 3g/t gold, 2.5 per cent copper and 7.2 per cent zinc from 41.2m.
The prospect’s third best hole produced 12m assaying 1.86g/t gold, 1.7 per cent copper and 2.5 per cent zinc from 43m, including 5m going 3.2g/t gold, 2.6 per cent copper and 1.2 per cent zinc from 48m.
The review was partly prompted by the meteoric rise in the gold price. Gold traded today at $5178.74 per ounce.
Including a gold resource would give the company scope to re-estimate the current Whundo mineral resource, thus enhancing the project’s economics and potentially achieving near-term gold-copper production.
GreenTech Metals executive director Tom Reddicliffe said: “We are very encouraged with these historic drilling results which confirm a strong contribution to potential production economics from the gold endowment, which mostly presents with the copper mineralisation at Whundo. This is a consequence of the significant increase in the gold price over the past 12 months that has seen an almost doubling of the gold price with 1 gram per tonne of in-situ gold now being approximately equivalent to in-situ 1 per cent copper metal per tonne.”
Armed with new encouragement, GreenTech plans to update its resource estimates to include the gold assays as a first pass to scope out the gold location, continuity and potential.
That exercise could grow some legs, as all the reported gold hits are consistently associated with copper mineralisation and are relatively shallow – mostly less than 60m depth downhole. This led Greentech to consider possible early cashflow from shallow open pit mining of at least some of its resource areas.
Regardless, the strong coincidence between gold and copper will almost certainly see GreenTech include gold in its normal analytical regimen from now on.
If mining ever gets off the ground, including gold credits from the company’s analytical outputs in any future base metals processing would help defray some of the costs.
The company has engaged industry mining consultancy Burnt Shirt to compare various mining and processing scenarios to identify any viable near-term mining options. Burnt Shirt would then proceed to a scoping study.
The first phase of that work is expected to be completed in the coming weeks.
GreenTech has already established resources at the Whundo and Ayshia mineralised zones and is exploring possible processing options at the nearby Artemis Resources’ Radio Hill and Anax Metals’ Whim Creek processing facilities.
All of GreenTech’s Whundo project resources sit within a single granted mining lease, which clears the company’s way to a mining permit.
So far, only Whundo and Ayshia have been assessed with gold in mind, but GreenTech says it will continue to explore the down plunge potential of other mineral shoots in the project area, including at Austin, Shelby and Ayshia.
Recent drilling as part of the company’s stage two program confirms the resource expansion potential and GreenTech still has untested plunging conductor plates at Austin, Shelby and Ayshia.
The stage two program aims to significantly expand the existing Whundo/Ayshia mineral resource of 6.2Mt at 1.12 per cent copper and 1.04 per cent zinc.
But the new potential copper-gold-zinc production - arising from strong gold and copper prices - means any future drilling programs will also focus on testing mineralisation continuity between Austin and Shelby. The work would be supported by the WA Government’s Exploration Incentive Scheme.
GreenTech will test the lateral and down plunge extent of the Ayshia and Austin shoots, shallow high-grade oxide mineralisation at Yannery and obtain core from Whundo and Ayshia for metallurgical testwork.
A near-term conceptual mine study will require prior completion of mineral resource estimates followed by Whittle optimisations for Whundo, Ayshia and Yannery, which will include copper, zinc and gold.
This will feed logically into further evaluation of the economics of near-term production, including further assessment of the Radio Hill site as a processing option for the Whundo feedstock.
If GreenTech can get all these ducks in a row, it could then start applying for a mining permit.
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