There’s growing evidence of a major extension of Chalice Mining’s already rich and large nickel, copper, platinum, gold and cobalt Gonneville discovery at Julimar, 70 kilometres northeast of Perth.
In a surprise statement to the ASX on Tuesday, Chalice revealed it had found strong evidence of a major extension of the Gonneville deposit to the north and west of the initial discovery, under a target area called Hartog which was one of the six areas slated for further testing.
According to Chalice’s ASX statement there are now a total of 27 areas along a 10-kilometre section of the 30-kilometre strike zone (and just to the north and now, deeper than expected) that are being or will be investigated by the company’s exploration and drilling teams.
Exploration will continue at Gonneville, and seven drill rigs are currently operating at Julimar with 27 planned drilling sites across the 10-kilometre Hartog–Dampier strike length.
Four of the rigs are working on the Hartog-Dampier target site and three at Gonneville defining the size and quality of the resource in the deposit
Chalice said that recent surveying indicates “significant” growth potential beyond the current resource with two-dimensional (2D) seismic surveying over the Hartog area highlighting the potential for plunge extension of the Gonneville (deposit) intrusion approximately 1.6 kilometres north-west of the resource and 500 metres below the surface.
This new area to the north-west is in addition to the already known 800 metres of “high grade plunge extent on farmland yet to be tested”.
The company said that at the moment this potential extension lies to the west and under the Hartog areas of interest which is also being explored at the moment.
Chalice admitted that drilling up to now on the Hartog prospect had been “too far east and above this interpreted position.” Chalice said “wide-spaced step-out drilling to validate the seismic interpretation has commenced.
It says it feels the new area is not part of the Hartog area of interest and that early drill holes have found geological structures very similar to those found at Gonneville.
“This is considered an exciting outcome which could materially expand the footprint of the Gonneville Deposit, given that the Gonneville Intrusion has so far proven to be consistently well mineralised,” Chalice said in the statement to the exchange.
In particular, given the sulphide-rich nature of the Gonneville intrusion, Chalice believes this extension could significantly expand the deposit. The company will is starting step-out drilling to validate the seismic interpretation of this new area.
Chalice says it is working towards development studies and regulatory approvals for the Gonneville deposit, which is the likely starter mine for the project.
This includes a scoping study for the prospect, which is evaluating a smaller ‘starter mine’ concept alongside a larger bulk mine concept.
The scoping study was supposed to have been completed in the current third quarter of 2022 but has been delayed to the end of this year by the growing complexities of the area and other issues, such as the availability of labour for the project, once the model is decided upon.
Chalice said in the statement the large size, variability (regarding mineralogy and grade) and growth potential of the Gonneville resource with further drilling meant it was exploring several development scenarios for Gonneville.
This includes open-pit and underground mining methods, two potential processing flowsheets and a broad range of processing plant throughputs and concentrate production rates.
Chalice says the Gonneville discovery “includes a significant higher-grade sulphide component, affording the project significant optionality in development and the potential to materially enhance project economics in the initial years of operations.”
Chalice adds that is also commenced discussions with several technical and funding partners for the potential starter mine.
In a separate presentation, Chalice said “Preliminary testwork to date on 15 sulphide composite samples from several geological domains (including higher-grade and lower-grade samples), demonstrates potential to produce two commercially attractive concentrates for sale from higher-grade sulphide material, with low levels of potentially deleterious elements
“Variability testwork, mineralogical investigations and flotation optimisation work continues on the nickel-cobalt- PGE concentrate.”
“Copper and PGE recoveries are robust at lower grades, however more work is underway to optimise flotation recovery of nickel and cobalt (and corresponding PGEs which report to the nickel concentrate)
“Several processing alternatives to enrich bulk Ni-Cu-Co-PGE concentrate being investigated in order to maximise recovery and payability, and potentially sell nickel- cobalt intermediate product direct to battery manufacturers.”
Chalice said it had received a $2.9 million Commonwealth Government grant “to evaluate these ‘midstream’ processing options.”
In November 2021, Chalice defined a Tier-1 scale maiden mineral resource estimate for Gonneville, considered one of the largest recent nickel-copper-PGE sulphide discoveries worldwide, and the largest PGE discovery in Australian history.
Its initial reserves estimate of 330 million tonnes was upgraded to 350 million tonnes in July of this year.
Chalice also revealed that drilling at the Dampier target along the strike zone has confirmed “encouraging evidence” of widespread sulphide mineralisation. Chalice believes this indicates a fertile mineral system that’s around 10 kilometres north of Gonneville.
“Drilling 6-10km further north of Gonneville has intersected a Gonneville-type ultramafic horizon over about 5.5km of strike length,” the company said in the ASX presentation.
The drilling found 9.6 metres (m) @ 0.2g/t 3E (gold, palladium and platinum). It also found 0.2% copper, 0.03% Co (~0.7% NIEq – nickel equivalent) from 203 metres below the surface.
Further, the drill results contained 41.6m @ 0.5g/t 3E, 0.1% Ni, 0.1% Cu, 0.01% Co (~0.4% NiEq) from 63 metres.
In the presentation, Chalice said the Gonneville Resource so far defined is just over just 2 kilometres of the 30 kilometres long Julimar Complex and the upside to the north in the new areas being worked “has the potential to transform the project.”
After the current Gonneville – Dampier area along the strike now being worked, there’s a further 18 kilometres of strike in the Baudin-Jansz-Torres zone to be tested and drilled, as well as the separate Flinders target towards the north east above the Torres area.
