Newly Discovered 9km Copper System Delivers Exceptional 22.5% Grades
Antares Metals (ASX: AM5) has unveiled what could be a transformative high-grade copper discovery at Antares Metals Ltd, with rock chip samples returning extraordinary copper grades up to 22.5% Cu along a previously unrecognised mineralised system stretching over 9 kilometres.
The discovery at the Cromwell prospect represents a district-scale opportunity that has somehow eluded previous explorers in this prolific copper region. With 36% of samples returning above 1% copper and structures up to 30 meters wide remaining open along strike, Cromwell has immediately established itself as the company's flagship prospect.
"AM5's commitment to targeted field activities and 'out of the box' thinking has led to the discovery of a 9km long mineralised structural corridor at the Cromwell prospect," said CEO Johan Lambrechts. "The discovery was made by field geologists making critical observations that led to the identification of a district-scale mineralised area not previously identified."
Key Highlights of the Cromwell Discovery
The high-grade copper discovery at Antares Metals Ltd features several remarkable characteristics that make it particularly noteworthy:
- A series of mineralised shear zones extending up to 9km long and 30m wide, all remaining open along strike
- 81 rock chip samples collected with exceptional results:
- 22.5% Cu maximum grade
- 17% of samples returned above 2% Cu
- 36% of samples returned above 1% Cu
- Multiple parallel shear zones identified (labeled A, B, C and D)
- Geological corridor hosting the target extends 20km within the company's project area
| Sample ID | Cu (%) | Au (ppb) | Ag (ppm) | Bi (ppm) | Mo (ppm) |
|---|---|---|---|---|---|
| ASR0114 | 22.5 | 190 | 0.7 | 0.4 | 1.6 |
| ASR0214 | 11.1 | 50 | 0.8 | 2 | 4 |
| ASR0209 | 5.8 | 50 | 2.1 | 66 | 3 |
| ASR0141 | 4.8 | 40 | 2 | 0.3 | 5.5 |
| ASR0205 | 4.3 | 100 | 44 | 104 | 7 |
Hidden Treasure: The Invisible Advantage
Perhaps most intriguing is that these copper-rich zones have remained invisible to previous explorers. The company noted that "copper oxide mineralisation is rarely visible on the exterior of the rocks and thus remains invisible to casual observation." This characteristic explains why such substantial mineralisation could have been overlooked in a region with extensive exploration history.
Antares geologists made the breakthrough by noticing that visible copper oxides only occurred where breccia veins intersected shear structures parallel to the primary layering in the basalt. This key observation led to the discovery of multiple mineralised shear zones of varying scale.
Understanding Shear-Hosted Copper Deposits
The high-grade copper discovery at Antares Metals Ltd appears to represent a shear and vein-hosted copper system within metabasalts. These systems can be particularly valuable because mineralisation often occurs not just in the veins themselves but also within the sheared host rock.
Shear-hosted copper deposits form when copper-bearing fluids migrate along structural weaknesses in the rock during deformation events. The Eastern Creek Volcanics (metabasalts) in the Mt Isa region have high background copper levels (around 200 ppm) and have been proposed as a possible source for copper within the Mt Isa orebody.
What Makes This Discovery Special?
What makes this discovery particularly promising is that the basalt shear fabric itself is well-mineralised with disseminated copper oxide aggregates and/or stockwork quartz veins. This significantly enhances the prospect's potential by increasing the overall mineralised volume beyond just the veins.
Furthermore, the extensive nature of the mineralisation across multiple parallel structures suggests a robust mineralising system with considerable potential for resource development.
Next Steps: Defining the Prize
Antares is planning a systematic approach to advance the Cromwell prospect:
- Additional mapping and sampling along the shear zones
- Soil geophysical surveys to detect mineralisation beneath cover
- Airborne gravity/magnetics and electrical survey techniques to identify high-grade zones
- Continued field activities to improve ranking and project phase development
The company is particularly excited by the scale of mineralisation, which it believes represents "a potential district-scale structure with immense mineralisation opportunity."
Why Investors Should Take Notice
This high-grade copper discovery at Antares Metals Ltd represents a potential game-changer for the company, which has a modest market capitalisation of just $4.6 million and cash position of $1.3 million as of June 30, 2025.
The Mt Isa region is one of Australia's premier copper districts, with world-class deposits and established infrastructure. For a junior explorer to identify a completely new, large-scale copper system in this mature exploration region is remarkable and speaks to both the quality of the technical team and the untapped potential that still exists.
Key Investment Considerations
- Scale: A 9km mineralised system with widths up to 30m represents significant tonnage potential
- Grade: Maximum copper values of 22.5% are exceptional by any standard
- Open potential: The system remains open along strike with the broader corridor extending 20km
- Overlooked opportunity: The "invisible" nature of mineralisation explains how this system was missed
- Multiple zones: Several parallel shear zones increase the overall potential of the prospect
Management Experience Driving Success
With an experienced management team led by Non-Executive Chairman Mark Connelly and CEO Johan Lambrechts, Antares appears well-positioned to advance this significant discovery. The company's systematic exploration approach and focus on field-based geological observations has already delivered results that vastly exceed what might be expected from its current market valuation.
Moreover, this discovery follows a trend of significant copper finds in Australia, including KGL Resources' major copper discovery at Jervois, Lachlan Star's copper-gold targets near CSA Mine, and significant copper grades at Celeste. Additionally, the Mutooroo sulphide extension copper discovery and the game-changing copper target at Ansa highlight renewed interest in copper exploration across the country.
As Antares advances the Cromwell prospect with additional field work and geophysics, investors will be watching closely to see if this discovery develops into the substantial copper resource that initial sampling suggests.
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