Thanks to more drilling in the past seven months, Gonneville – the world’s biggest nickel sulphide discovery this century – has grown in size, along with the amount of palladium, platinum, gold, nickel and cobalt Chalice Mining’s (ASX:CHN) prospect contains.
Chalice’s huge green metal prospect north east of Perth is also Australia’s largest ever discovery of so-called 3E metals, platinum and palladium in association with gold.
Now as a result of drilling since the original Gonneville reserves estimate last November, Chalice says the project is heading towards major development decisions later this year as the company steps up work to tighten reserve quality data and other parameters (such as metal yields from the ore) ahead of a scoping decision on an initial mining plan due in the next couple of months.
Gonneville is the first major discovery at Julimar for Chalice which has said is a ‘world-class’ prospect (along a now 30 kilometre long strike zone) and the latest drilling has seen a significant boost to grades, resource and contained metal that adds billions of dollars in future value.
Chalice says drilling since the first estimate of reserves at Gonneville in November, has seen the Measured Resource Estimate (MRE) rise to 350 million tonnes at 0.96 grams to the tonne (g/t) platinum, palladium and gold (3E), 0.16% nickel, 0.1% copper and 0.015% cobalt.
That is up from the November’s first estimate of 330 million tonnes of ore at 0.94 grams to the tonne 3E, 0.16% nickel, 0.10% copper and 0.16% cobalt.
Contained metals now stand at 11 million ounces of 3E metals, up from 10 million in November, 560,000 tonnes of copper, up from 530,000 tonnes, 360,000 tonnes of copper, up from 330,000 and 1,000 more tonnes of cobalt for a total of 54,000 tonnes of that metal.
Chalice points out that “Gonneville remains open at the Julimar State Forest boundary to the north, where four rigs are continuing an initial drill program at the Hartog-Dampier targets. The Deposit also remains open beyond a depth of ~700m metres “with the potential for further material growth.”
Instead of the initial four areas of interest, starting with Gonneville at the southwest end of the then 26-kilometre strike zone, there are now at least seven areas of interest along the 30-kilometre strike one. Gonneville is just 7% of the strike zone.
Since the November statement the company has undertaken shallow infill drilling to upgrade the Gonneville resource from the inferred category to indicated. Positively, the proportion of the indicated resources has now increased from 45% to 70% of the MRE total, Chalice says.
Part of that work has outlined in more detail the sulphide component of the discovery which now could be a mine in its own right.
Chalice said the higher-grade sulphide component of the resource “also increased to 82 million tonnes at 1.7 grams to the tonne 3E, 0.21% nickel, 0.20% copper and 0.030% cobalt, containing 4.5 million ounces of 3E, 180,000 tonnes of nickel, 170,000 tonnes of copper and 16,000 tonnes of cobalt.
“This higher-grade component affords the project significant optionality in development and could potentially materially enhance project economics in the initial years of operations,” Chalice told the ASX in an update.
In other words, the sulphide part of the deposit could be mined first to provide higher revenues and cash flow sin the earlier years to help pay down debt and set operating costs.
Chalice CEO, Alex Dorsch, said in the statement the resource includes a mix of oxide, transitional and sulphide mineralisation, reported at two different cut-off grades to highlight the scale and development optionality the deposit affords.
“The significant higher-grade component of the resource provides excellent optionality for any future development and could potentially materially improve project economics in the initial years of operation. This is a key focus of the project Scoping Study, which is due to be completed in Q3 2022,” he said.
“The work we have completed since publishing our maiden resource in November last year continues to demonstrate the world-class endowment, scale and quality of the Gonneville deposit,” Dorsch said.
“Importantly, 90 per cent of the resource above a depth of 250m is now classified as indicated, which represents a major de-risking step for the project.
“It is also evident from recent exploration results that there is enormous growth potential both at depth at Gonneville and along the effectively untested Julimar Complex to the north.
“While we already have a Tier 1 scale deposit which has the potential to underpin a world-class, long-life green metals project, the resource base is expected to continue to grow,” he said.