PhosCo Strikes High-Grade Phosphate Discovery at KH Gasaat Project
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:
"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.
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.
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.
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.
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 |
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:
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.
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.
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 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 |
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:
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.
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:
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.
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:
Several attributes make this opportunity worthy of investor attention:
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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