Phosco Ltd
PhosCo Strikes High-Grade Copper, Silver and Zinc at King's Eye — A Second Project Takes Shape in Tunisia
PhosCo Ltd (ASX: PHO) has announced high-grade results from rock chip sampling at the King's Eye (Ain El Bey) Prospect within its 100%-owned Simitu Project in northern Tunisia. The PhosCo high-grade copper silver zinc results at King's Eye Tunisia include copper assays reaching 21.2% Cu, silver hitting >100 g/t Ag, and zinc samples exceeding the 30% upper detection limit, establishing King's Eye as a genuinely compelling multi-metal target warranting immediate follow-up exploration.
Key highlights at a glance:
- 21 rock chip samples returned >1% Cu, with 5 samples exceeding 10% Cu and a peak of 21.3% Cu
- 8 silver samples exceeded 31 g/t Ag, including 6 samples above 62 g/t Ag and one above the 100 g/t upper detection limit
- Antimony values up to 1.49% Sb, with 5 samples over 0.5%
- 19 zinc samples exceeded 1% Zn, with 6 samples above the 30% analytical upper limit
- Lead up to 12.65% Pb across the zinc oxide zone
- Ground geophysics (ERT and IP) successfully mapped historical underground workings and identified a strong chargeability anomaly at depths exceeding 100 metres, pointing to a potential sulphide extension below the historic mine levels
"These are highly promising results in a fertile tectonic setting with a geophysical target at depth. Given the potential upside, we are planning immediate follow up. And while PhosCo remains firmly focused on its key Gasaat Phosphate Project, King's Eye and the broader Simitu Project represent a compelling opportunity to advance a second project prospective for highly sought-after metals in this underexplored region, leveraging PhosCo's first mover advantage in Tunisia."
— Taz Aldaoud, Managing Director, PhosCo Ltd
It is important to note that these rock chip samples were selectively collected to characterise mineralisation types and should not be taken as representative of overall grade across the broader prospect. They do, however, powerfully demonstrate the presence of genuinely high-grade material at surface and in historical workings.
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Two Distinct Mineralisation Systems — Double the Opportunity
One of the most significant takeaways from this programme is the identification of two separate and unrelated mineralising events within King's Eye, each with its own character and economic significance.
Sulphide Cu-Sb-As-Ag Mineralisation
This system is characterised by copper-rich sulphide veins and replacements within limestone beds. The mineralogy includes chalcopyrite, bornite, and sulphosalts (tennantite-tetrahedrite), consistent with a high-temperature hydrothermal system.
Peak formation temperatures have been independently estimated at up to 350°C in academic studies of the region, pointing to a deep-seated magmatic component. Mineralisation occurs as fracture-filling veins 0.5 to 1 metre wide, with at least one vein confirmed at 200 metres in length cross-cutting multiple rock units.
Oxide Zn-Pb (Mississippi Valley Type) Mineralisation
The zinc mineralisation occurs in karsted Upper Cretaceous limestones and at the contact zone between Triassic evaporites and Upper Cretaceous marls. This style is interpreted as a Mississippi Valley Type (MVT) deposit — a well-understood global deposit class known for producing large, high-grade zinc-lead orebodies.
Select Assay Results — The Numbers Speak for Themselves
Top Cu-Sb-As-Ag Samples (>10% Cu)
| Sample No | Cu (%) | Sb (ppm) | As (ppm) | Ag (ppm) | Fe (%) |
|---|---|---|---|---|---|
| 200-8 | 21.30 | 1,630 | 7,620 | 21.2 | 34.2 |
| 492 | 15.45 | 6,530 | 11,200 | 64.4 | 41.6 |
| 200-11 | 13.80 | 14,900 | 25,000 | 78.4 | 37.4 |
| 200-9 | 13.35 | 4,570 | 4,560 | 28.8 | 39.4 |
| 200-13 | 11.10 | 12,500 | 31,000 | >100 | 40.1 |
Top Zn-Pb Samples (>20% Zn)
| Sample No | Zn (%) | Pb (%) | As (ppm) | Fe (%) |
|---|---|---|---|---|
| 505 | >30.0 | 0.38 | 168 | 0.24 |
| 518 | >30.0 | 0.94 | 1,345 | 11.75 |
| 519 | >30.0 | 12.65 | 9,200 | 0.56 |
| 520 | >30.0 | 3.20 | 1,390 | 1.20 |
| 521 | >30.0 | 0.48 | 586 | 1.02 |
| 515 | 23.60 | 10.50 | 6,740 | 0.36 |
| 516 | 21.20 | 0.68 | 2,890 | 9.36 |
What the Geophysics Is Telling Us
Beyond the surface chemistry, perhaps the most strategically important finding from this programme is what the ground geophysics revealed underground. Four geophysical profiles were run using two complementary techniques — Electrical Resistivity Tomography (ERT) and Induced Polarisation (IP).
The results were instructive on two fronts:
- ERT successfully mapped the historic underground workings as resistivity highs, confirming the workings extend only to approximately 40 vertical metres — consistent with historical records of small-scale mining
- A strong IP chargeability anomaly was identified at depths exceeding 100 metres on Sections 1 and 4, interpreted as potentially reflecting sulphide mineralisation that has never been tested by drilling
The combination of surface high-grade copper mineralisation and a deep IP anomaly creates a compelling drill target. Furthermore, the historic mine never went deep enough to test what lies below.
Understanding the Tools — What Is Induced Polarisation (IP) and Why Does It Matter?
Induced Polarisation (IP) is a geophysical technique that measures the ability of rocks in the subsurface to temporarily store an electrical charge — a property called chargeability. When a current is injected into the ground and then switched off, sulphide minerals release their stored charge slowly, and this response is measured at surface.
Why Does IP Matter for Investors?
IP is widely regarded as one of the most reliable geophysical tools for detecting disseminated or vein-hosted sulphide mineralisation at depth — even at relatively low concentrations. A strong, coherent IP anomaly beneath a known historic copper mine is a meaningful signal, suggesting the mineralising system continues at depth, untouched by historical mining that only ever reached 40 metres vertically.
Key geophysics terms used in this announcement:
| Term | Plain English Meaning |
|---|---|
| ERT (Electrical Resistivity Tomography) | Maps how well rocks conduct electricity underground; useful for identifying voids, faults, and rock types |
| IP (Induced Polarisation) | Detects sulphide minerals at depth by measuring their ability to store and release electrical charge |
| Chargeability | The strength of the IP response — higher chargeability suggests more sulphide mineral content |
| Resistivity | Measure of how strongly a material resists electrical flow; useful for distinguishing rock types and voids |
| MVT (Mississippi Valley Type) | A globally recognised deposit style producing large zinc-lead orebodies, typically in carbonate rocks |
| Gossans | Iron-rich weathered rock at surface formed from the oxidation of sulphide minerals — a classic surface indicator of sulphide mineralisation below |
The Geological Setting — Why Tunisia?
The Simitu Exploration Permit covers 396 km² and is centred on the Medjerda Thrust Zone in northern Tunisia — one of several thrust systems forming part of the Atlas Mountains, a well-endowed metallogenic belt spanning northern Africa.
The Atlas Mountain belt is a known host to polymetallic deposits. The convergence of the African and Eurasian plates created the structural framework — thrust faults, folds, and nappe stacking — that channelled hydrothermal fluids through the crust. These fluids deposited copper, silver, antimony, zinc, lead, and in some localities, gold.
King's Eye sits within a 30km-long mineralised corridor across the Simitu Project. Historical production data records that the Chouichia and King's Eye deposits together produced approximately 2,000 tonnes of copper and several thousand ounces of silver during intermittent mining between the early 1900s and 1970 — all from shallow workings with primitive methods and no systematic modern exploration.
Summary of Simitu Project Scale
| Feature | Detail |
|---|---|
| Permit area | 396 km² |
| Mineralised corridor | ~30 km strike length |
| Permit holder | Himilco Resources Ltd (100% subsidiary of PhosCo) |
| Permit granted | 7 November 2023 |
| Permit term | 3 years, renewable for a second 3-year term |
| Previous systematic exploration | None prior to current PhosCo programme |
Analogies That Frame the Opportunity
PhosCo's geologists have drawn a conceptual comparison between King's Eye and the Jinman sediment-hosted vein-type copper deposit in China's Lanping Basin. While the two deposits differ in detail, the analogy is instructive: at Jinman, narrow near-surface copper veins associated with convergent tectonic settings extend and broaden at depth into economically significant targets.
The same structural framework at King's Eye — narrow surface veins cutting multiple rock units, a deep IP anomaly, and geochemistry consistent with a magmatic hydrothermal origin — supports a conceptual model where the system could develop significantly below the historic mine levels.
Three possible deposit types are being considered for King's Eye:
- Intermediate to high sulphidation epithermal system fed by deeper igneous activity
- Vein systems thickening at depth into breccia pipes
- Carbonate Replacement Deposits (CRDs) at the tops and peripheries of porphyry-driven systems
Each of these deposit types has the potential to host economically significant copper and silver mineralisation — and each warrants drill testing to determine which model best fits the King's Eye geology.
Next Steps — What Happens From Here?
PhosCo has stated that interpretation of exploration data is already underway and is directly guiding the design of the next phase of work. Planned activities include:
- Detailed geological logging of existing outcrop and historical workings to define structural controls on mineralisation
- Geochemical analysis and mineralogical studies to refine vectors toward high-grade zones
- Additional geophysical profiling to build a more complete 3D picture of the system's architecture
- Drill targeting based on the combination of surface geochemistry and the IP anomaly at depth — the most anticipated near-term catalyst
The IP anomaly below 100 metres on Sections 1 and 4 represents the primary drill target. In addition, a drill intersection confirming sulphide mineralisation at depth would be a material development for the project.
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Why Investors Should Keep Watching PhosCo
PhosCo occupies an interesting position: a phosphate-focused explorer with a potentially significant polymetallic project developing alongside its flagship. The Simitu Project is not a distraction from the Gasaat story — it is an additional layer of value being built within the same company, leveraging existing in-country knowledge and relationships.
The PhosCo high-grade copper silver zinc results at King's Eye Tunisia confirm that:
- High-grade copper, silver, and zinc mineralisation is present at surface and in shallow workings
- The system almost certainly extends below 100 metres based on IP geophysics
- The broader 30km corridor contains multiple other untested targets
- A drill programme is being planned as the immediate next step
What Makes King's Eye a Standout Opportunity?
Several attributes make this opportunity worthy of investor attention:
- First mover position in an underexplored region with established historical production and clear geological analogues
- High-grade surface results demonstrating the mineralising system is real — copper to 21.3%, silver to >100 g/t, zinc to >30%
- Geophysical target at depth never previously drill-tested, directly below known mineralisation
- Dual mineralisation styles providing multiple potential development paths
- 30km prospective corridor with multiple additional prospects beyond King's Eye
- Copper, antimony, and silver — metals with strong current demand profiles, particularly in the context of electrification and energy storage
Key Differentiators
| Factor | Detail |
|---|---|
| Ownership | 100% — no joint venture dilution |
| Prior modern exploration | Minimal — effectively greenfields |
| Depth tested historically | Only ~40 vertical metres |
| IP anomaly depth | >100 metres — never drilled |
| Prospect corridor | ~30 km across 396 km² tenement |
| Peak copper grade | 21.3% Cu (selective rock chip) |
| Peak silver grade | >100 g/t Ag (at upper detection limit) |
| Peak zinc grade | >30% Zn (at upper detection limit) |
However, the drill results, when they come, will be the pivotal moment for this project. If the IP anomaly at depth translates into significant sulphide mineralisation in drill core, King's Eye could quickly evolve from a promising historical prospect into a project with genuine scale.
The PhosCo high-grade copper silver zinc results at King's Eye Tunisia represent more than just impressive numbers — they validate the geological model and establish a clear pathway to drill testing at depth. For investors tracking the company's diversification beyond phosphates, these results demonstrate that the Simitu Project has genuine merit as a standalone opportunity, positioning PhosCo as an early-stage multi-commodity explorer in a region that has seen minimal modern systematic exploration.
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