Since an active Western Australian-based explorer was taken out by a joint venture involving billionaire Gina Rinehart due to the former’s Pilbara lithium holdings, questions remain of what is in store for one of the country’s most exciting emerging greenfields base metal plays.
The project is Andover, located some 35 kilometres south east of Karratha and immediately south of the small town of Roebourne, which was developed by then ASX-listed junior
Azure Minerals before it was taken over by Rinehart’s Hancock Prospecting (along with Chilean lithium company Sociedad Quimica y Minera de Chile) in a deal worth a reported $1.1 billion.
Just before Azure turned its attention to the Andover lithium play, which sits well to the south west near the coastal town of Onslow, it had established a maiden mineral resource for the Ridgeline deposit of 1.3 million tonnes at 1.11 per cent nickel, 0.46 per cent copper and 0.05 per cent cobalt.
In February 2023, the junior announced the project’s total mineral resource was 60Mt at 1.11 per cent nickel, 0.47 per cent copper and 0.05 per cent cobalt for 97,300t of contained nickel. These latter numbers included both the Ridgeline and Andover ore bodies.
Whether or not Hancock Prospecting will pursue this advanced exploration play or perhaps spin it out is still unknown, particularly as the nickel price has tanked thanks primarily to an arrangement between Indonesia and China.
Nevertheless, the base metal is classified as critical, while the project itself remains quite a compelling prospect given the speed at which the mineral resource was established and the fact it sits in a prime spot within the west Pilbara – one that is definitely amenable to further development.
On the exploration front it’s really no surprise the numbers were established so expeditiously given the two men behind its evolution represent some of WA’s best geological thinkers.
The first was Azure boss Tony Rovira who, along with the late Terry Grammer, discovered the high grade Cosmos nickel mine near Leinster in the 1990s. His company owned 60 per cent of Andover.
Meanwhile, the second was legendary WA prospector Mark Creasy, whose namesake Creasy Group held the remaining 40 per cent.
In short, it only took Azure two years to establish the initial resource, which was no mean feat given it had come across a potentially significant base metals prospect in what is predominantly iron ore country.
The second major aspect to take into account when it comes to Andover and Ridgeline is their location.
Situated in a mature mining district where numerous previous (and existing) extraction activities for various commodities, including nickel-copper-cobalt), have taken place, the nearby established infrastructure is comprehensive and more than capable of servicing the resources sector.
The base metals grades throughout Ridgeline are sufficiently high enough to potentially provide material to feed to a processing facility, while – according to Azure at least – the cut-off grade adopted is reasonable for an underground operation and similar to comparative peer nickel mines in the region.
Moreover, there are no known legal, social, or environmental constraints at the project that would prevent accessing the resource.
In his announcement to the ASX at the beginning of last year, Rovira indicated that there continued to be “excellent potential to significantly expand the resource base” of Andover through ongoing exploration success.
“With the final and deepest drill hole at Ridgeline returning the best mineralised intersection to date (14.5 metres at 2.26 per cent nickel), I am confident that we can grow this resource even further,” he said.
“Ridgeline is blind to surface, which increased the challenge of identifying and defining the mineralisation.
“Given the technical understanding and knowledge that our team has built up through systematic exploration of the project area, I am confident that the team can deliver more discoveries.”
Another non-iron ore exploration play in the Pilbara which is gaining momentum is Novo Resources Corporation’s Egina gold camp JV around 120km south east of the mining town of Karratha.
Covering an 80km long contiguous tenement pack, the project area hosts Novo’s current high priority regional targets at Nunyerry North and Becher.
The tenure contains a series of structurally complex, gold-fertile corridors and is hosted by rocks of the Mallina Basin in the north and mafic/ultramafic sequences further to the south.
This belt will be the primary focus of Novo’s 2024 Pilbara field programs. Its venture partner is De Grey Mining Ltd, a cornerstone investor which is spending up to $25 million on exploration on Becher and its adjacent tenements within four years to earn a 50 per cent direct interest in the undertaking.
Combined, the exploration partners hold some 2500 square kilometres of prospective ground in the Mallina Basin.
Importantly, Egina’s JV tenements are considered highly prospective for significant intrusion-related gold deposits, with similar attributes to De Grey’s evolving 10.5Moz Hemi deposit.
All up, Nova holds 7000 square kilometres of Pilbara land, with the other prospects being the Karratha District and Balla Balla. It also has another project in Victoria (Belltopper).
During a recent roadshow, the explorer indicated it was particularly interested in Nunyerry North, calling it a “high priority exploration target with potential to become a significant gold project”.
Located 150km from Port Hedland, this tenement is also subject to a JV, with Novo holding 70 per cent and the remainder being held by Rockford Metals Pty Ltd, another Creasy vehicle.
Following an RC program of 30 holes for 2,424m across 200m of strike conducted last November, Novo resubmitted all the significant drill intercepts for multi-pot assaying.
The final result was calculated as the weighted average of the pots’ grade and weight, which produced larger overall sample weights and more accurate assay numbers.
