GreenTech Metals has completed planning for up to 4000m of diamond drilling for its second phase program at the company’s Whundo volcanogenic massive sulphide (VMS)–style copper-zinc project in WA’s West Pilbara.
The campaign seeks to confirm the potential for and likely scale of one or more base metals resources lurking below the shallow historic Whundo and Ayshia open-pits and within the 2km-long zone separating them.
Recent geophysical exploration has highlighted multiple electromagnetic conductors along the strike of the six known centres of mineralisation or shoots comprising the overall target trend.
The six zones are commonly referred to, from south-west to north-east, as Whundo East, Whundo West, Austin, Shelby, Yannery and Ayshia.
Whundo has been the subject of the most significant open-pit mining, while the smaller Ayshia open-pit sits at the opposite end of the trend and Yannery features some minor shallow diggings.
The Whundo resource footprint embraces an estimated remaining 5.3 million tonnes going 1.1 per cent copper and 0.8 per cent zinc, while Ayshia sports a smaller remanent resource estimated at 0.92 million tonnes at 1.3 per cent copper, 2.3 per cent zinc, 0.1 per cent lead and 0.2g/t gold.
Initially, the proposed drilling will address the less well-explored Austin, Shelby, Yannery and Ayshia and will focus on testing the previously-modelled conductor plates at those sites.
GreenTech expects that downhole electromagnetic (DHEM) surveys will also be undertaken on some of the new holes to confirm or extend previous conductors and potentially also bring additional targets to light.
The company anticipates the results of the upcoming DHEM surveys will assist with planning additional follow-up drilling on new targets which, if significant, could even be drilled during the current campaign.
Notably, a further combined 2km of the most obvious prospective zone along the historic line of pits and diggings remains open to both the east and west of known mineralisation within GreenTech’s ground.
GreenTech Metals executive director Tom Reddicliffe said: “Following hot on the heels of a successful first stage of drilling, this next campaign will get underway this year to further test potential extensions to the mineralised shoots comprising the Whundo VMS cluster. We eagerly await the outcome of testing the exceptional Shelby conductor whose scale eclipses other targets in the field. This target is a clear standout and will be a priority to be drilled. Given the nature of VMS clusters and the multiple opportunities for resource growth, we believe a project with around 10-15Mt would make a significant difference to the economics of the Whundo Copper project and represents a potentially achievable target for exploration going forward.”
The company believes the close spatial relationship between the known mineralised shoots with respect to plunge and the mineralisation thickness defined so far all point to the possibility of them being part of significant VMS-type mineralising event which remains open along strike and at depth.
Currently, the Austin and Shelby targets are seen as potentially high-grade deep resources, while Yannery appears to be a shallow resource with potentially deep extensions.
Austin is a plunging mineralised copper-zinc shoot sitting about 30m underneath the Whundo East copper-zinc resource. Both Austin and Whundo East plunge northwards at between 30 and 40 degrees inclination.
Two of GreenTech’s holes produced good primary intercepts from Austin. One 19m hole came in at 0.81 per cent copper and 0.15 per cent zinc from 225m, while the other nailed 16m going 1.2 per cent copper, 0.12 per cent zinc and 0.035g/t gold from 230m.
Both holes contained up to 1m intersections at 5.4 per cent copper from 226m in the first holes, while the second hole gave up 3m assaying 2.13 per cent copper, 0.2 per cent zinc and 0.043g/t gold from 235m.
The company is buoyed by the significant thicknesses and grades and because the Austin zone appears to be copper-dominant. Additionally, the big, fixed loop EM (FLEM) conductor indicates that Austin harbours strong potential to significantly complement the Whundo resources.
Drilling of Shelby by Fox Resources in 2006 returned an intercept of 11.25m going 1.6 per cent copper from 391.25m, including 5.8m running 2.4 per cent copper from 391.25m.
Additionally, a hole plugged into Shelby by GreenTech in 2022 yielded a 14m intercept assaying 0.5 per cent copper from 417m.
At Yannery, limited exploration drilling last year confirmed supergene copper mineralisation, intercepting up to 8m going 5.2 per cent copper from 31m which includes 1m at 23.1 per cent copper and 37.1g/t silver from 34m.
Meanwhile, the Ayshia centre is shaping up as a possible high-grade depth extension to its current resource. Its significant 0.92 million tonne copper-zinc resource has been defined down plunge by drilling for to 300m and is up to 100m thick. It remains open at depth.
Previous drilling has highlighted high copper grades at depth including 23.7m assaying 3.2 per cent copper, 0.4 per cent zinc from 209m and a second hole intercepting 13.97m going 3.4 per cent copper from 243.63m.
A third hole bored through 20m at 0.6 per cent copper, 1.0 per cent zinc and 0.11g/t gold from 250m.
Ayshia’s mineralisation is indicated by a moderately conductive body about 25m to 35m wide and a 200m strike down-plunge at an inclination of about 40 to 50 degrees.
GreenTech is finalising field preparations for the program which it expects to launch this month with drilling contractor Topdrill. The program will be funded by the company’s recently-completed $2.3 million placement and an EIS grant of up to $140,000 from the WA Government.
Experienced drilling contractor Topdrill has elected to take $1m of its fees in GreenTech stock. No doubt Topdrill has seen a project or two and its election to take a million dollars in GreenTech stock over cash is notable.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
