• Hillgrove identifies Kanmantoo Deeps as being a potential repeat of the entire Kanmantoo copper-gold deposit
  • New area is 400m north and along strike of the main Kavanagh copper-gold system
  • Drilling planned to test the new target


Hillgrove’s recently completed 3D AMT/MT resistivity survey has led to the identification of what could be its most significant discovery – a potential repeat of the entire Kanmantoo copper-gold deposit.

With the company charging along on the path to restarting copper production in the first quarter of 2024, the find has the potential to substantially increase mine life and production.

The fully-funded Stage 1 development of Hillgrove Resources’ (ASX:HGO) Kanmantoo underground mine will access about 4.5Mt of project’s current underground resource of almost 7Mt to produce 43,500t of copper and 11,500oz of gold over 45 months.

Capex is a low $25m – thanks to existing infrastructure such as the 3.6Mtpa processing facility – while all-in sustaining cost is just $8051/t of copper equivalent.

This delivers impressive net present value and internal rate of return – both measures of a project’s profitability – of $165m and 231% respectively.

Adding interest, the Stage 1 mine plan focuses on just two of the nine known mineral lodes on the mining lease that were either drilled or mined as part of the previously producing open pit.

These lodes remain open at depth and along strike and drilling is already underway to aimed at expanding mine life and annual copper production.

An Exploration Target of between 10Mt and 20Mt grading 0.9% to 1.3% copper and 0.1g/t to 0.3g/t gold has been estimated for these Mine Lease areas.


Long section of the location of the Kanmantoo Deeps target. Pic: Supplied (HGO).


Going Deeper: Massive potential for scale

While the potential for further resource growth at the known Kanmantoo lodes is hugely positive, it is dwarfed by the potential to find an outright repeat of the entire deposit.

So just how did such a discovery come about?

The final piece of the puzzle was the recently completed 3D AMT/MT resistivity survey which identified a strong low resistivity (high conductivity) zone about 400m north and along strike of the existing underground mine development.

This conductivity zone is interpreted to be the faulted extension of the main Kavanagh copper-gold system and is coincident with strong gravity and magnetic anomalies, both of which are geophysical attributes of the Kavanagh mineralisation.

Even with a 50% reduction of the conductivity zone, Hillgrove has estimated that there is an Exploration Target of between 50Mt and 80Mt at the new Kanmantoo Deeps zone.

Though no grade range has been estimated to date, the company indicated that Kanmantoo Deeps could have grades similar to those at the Kavanagh system.

Separately, the successful testing of previous Exploration Targets by the Emily Star and Spitfire holes, which returned assays of 35.1m at 1.29% copper and 45.4m at 1.19% copper respectively, has given the company the confidence to continue with exploration to expand its copper production profile and mine life within the Mine Lease area.

Hillgrove now plans to test Kanmantoo Deeps by drilling the target about 400m to 600m from the proposed underground decline.


This article was developed in collaboration with Hillgrove Resources, a Stockhead advertiser at the time of publishing.

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.