West Forbes

Geological setting and mineral system

West Forbes lies in the northern Junee–Narromine Volcanic Belt of the Ordovician Macquarie Arc — the principal host of porphyry and high-sulphidation epithermal Cu–Au mineralisation in NSW, whose type deposits (Northparkes, Lake Cowal) are concealed and were defined from drilling rather than outcrop (R00042286). Prospective arc basement is concealed here beneath an interpreted 100–140 m of Cainozoic and Mesozoic cover. The target model is a concealed, distal-to-buried intrusive centre expressed as a large (≈5 mgal) gravity low. That an altered intrusive body sits beneath the low is a geophysical inference, not an observation: no historical hole has reached fresh Ordovician basement at the feature's interpreted centre, so the intrusive interpretation is held against the operator's own base case that the low is a sediment-filled graben.

The grades — what the system has already demonstrated

Result (GSNSW open-file, verbatim-sourced)	Confirmation status / disclosed discrepancy and Phase 1 resolution
SP2, base of hole — 641 ppm As, 42 ppm Mo, 0.014 g/t Au (EL 4909, 1998; R00042286)	Hydrothermal pyrite–marcasite quartz gravel confirmed petrographically (Dr J. Barron). Molybdenite not identified and the Mo source was not determined; the hole did not reach fresh basement. Reported as an anomaly, not a porphyry-pathfinder signature.
SP1 — 0.11 g/t Au over 17–23 m (EL 4909, 1998; R00042286)	Hosted in transported cover gravel and explicitly not an in situ basement result; SP1 was percussion-only with no core recovered. Best-treated as detrital/hydromorphic gold.
Bore 36079 cuttings, ~142 m — 0.042 g/t Au, 630 ppm As (EL 4909; R00020131)	Single cuttings sample; the operator described it as inconclusive and the on-tenure location of bore 36079 is not established. Phase 1 confirms the bore position before it is relied on.
FEL-005 / FEL-006 — 565–765 ppm As (EL 3681; R00004918)	ALS batch M407 is labelled “DRILL”, dated ~11 months before licence grant, and carries no collar locations, so it cannot presently be tied to in-tenure sampling. Phase 1 recovers the primary ALS ledger and collars.
LC01 — up to 830 ppm Cu (Lake Cowal, adjacent; R00001885)	Best district surface Cu, on adjacent ground ~10–25 km away. Carried as a regional analogue and vector only — not a West Forbes footprint result.

No ore-grade intercept exists anywhere in the historical record; every gold value is pathfinder-level. The case is a system-vector case, not a grade case — and this is the only section in which intercepts appear.

Exploration history — five licences, every departure documented

Period	Operator (licence)	Model targeted	Documented departure reason (R-number)
1990–91	Newmont / Newcrest (EL 3681 “Forbes”)	Buried magnetic pluton; calcareous-unit skarn beneath alluvium	Proposed gravity and water-bore testing but relinquished without drilling the interpreted pluton (R00004918)
1991	Geopeko (EL 3669 “Bogan Gate West”)	Cu–Au in mapped surface lithologies	RAB/RC repeatedly abandoned in gravel without reaching bedrock; judged unprospective for the alkaline suite sampled (R00003373)
1991–92	Geopeko (EL 3760)	Epithermal Au–Ag under cover	1:25,000 mapping only; concluded any mineralisation sub-economic beneath cover; relinquished (R00001562)
1992	Newcrest (EL 3623/3627 “Lake Cowal”, adjacent)	Gravity-high “buried hill” bulk-tonnage Au	Aircore defeated by depth to basement; follow-up XRD failed to upgrade the advanced-argillic indications; relinquished (R00001885)
1996–99	Caledonian Pacific / Goldrap (EL 4909 “Southparkes”)	Concealed porphyry / high-sulphidation Cu–Au	Drilled three holes on the northern margin, confirmed hydrothermal mineralogy, then attributed the gravity low to a graben and relinquished — the centre was never drilled (R00042286)

Every departure is documented as economic-, cover-depth- or model-driven; no campaign drilled and rejected the concealed target centre. The recurring failure mode is the mismatch between deep cover and shallow or marginal testing — not barren rock.

Why the grade is still available — in the operators' own record

Wrong commodity, wrong model. Each operator left for reasons its own reporting records as economic or model-driven, not because the concealed target was tested and failed. Caledonian Pacific attributed the ≈5 mgal gravity low to a sediment-filled graben and relinquished after three margin holes. Geopeko judged the ground unprospective for the alkaline A-type lithologies it sampled at surface — a conclusion the synthesis accepts for those rocks, but which does not bear on the concealed calc-alkaline targets to the east that Geopeko never tested. Newcrest, at adjacent Lake Cowal, walked away from a live advanced-argillic vector because the depth to basement defeated its aircore method.

The analytical gap. CAADIA's audit of the open-file record identifies element suites and datasets that were never generated. The EL 3669 peralkaline A-type suite was never assayed for the rare-earth elements, niobium, zirconium, yttrium, uranium or fluorine that characterise peralkaline systems, so that potential is unmeasured; the 1997 airborne magnetic and radiometric grids were never reprocessed to modern standards; and the CSIRO groundwater gold–molybdenum results table that the operator used to justify the 1998 drilling was never released in the reports held. Against those gaps sits one independent pathfinder confirmation: the petrographically confirmed pyrite–marcasite assemblage at the base of SP2, carrying 42 ppm Mo and 641 ppm As.

The untested target. The formal historical finding was recorded and never actioned. The operator's own drilling contractor concluded, in its appendix to the final report, that “the centre of the gravity low and associated interpreted magnetic anomalies have not been drill tested” (R00042286, Appendix III — Rangott Mineral Exploration / J. Parton, Conclusion 3). The three 1998 holes bracketed the northern margin; the interpreted centre, beneath ~120 m of cover, remains untested below ~150 m vertical to this day.

The miss, precisely. No operator drilled the target. Five licences over a decade surveyed, sampled and shallow-drilled the West Forbes ground, and Caledonian Pacific put three diamond holes into the northern margin of the ≈5 mgal gravity low in 1998 — but not one hole was ever collared over the low's interpreted centre, and no hole has reached fresh Ordovician basement beneath it. The centre sits below ~120 m of cover and ~150 m vertical, untested to this day. So the ground was never condemned on evidence: each operator left for economic, cover-depth or model reasons — running out of budget, using a method the deep cover defeated, or reading the low as a barren graben — while the one volume where a concealed system's grade would concentrate was left undrilled. That untested centre is the miss, and closing it is a single well-sited hole.

System scale and the commercial lens

Footprint. The primary feature is a large (≈5 mgal), kidney-shaped gravity low, slightly larger than the Northparkes anomaly, at an implied one-to-two-kilometre scale; a second intrusion-related target sits ~15 km west within the same northing band (~6,290,000–6,310,000 mN). The 1998 holes bottomed at 128 m, 121.6 m and 172 m on the margin — none reached the interpreted centre or fresh basement below ~150 m vertical, whereas systems of this class extend well below the depth so far tested. These are anomaly and system dimensions only; no tonnage is implied.

Model-class analogue. The type deposits of this model class are Northparkes (porphyry Cu–Au) and Lake Cowal (Au). In the synthesis's exact words, published endowment figures for these deposits “are cited for analogue and context purposes only and are not reported in compliance with the JORC Code (2012)”, and “the analogue is used to characterise deposit style and the importance of testing beneath cover, not to imply equivalent endowment on the West Forbes ground.” The conservative case is carried honestly: the operator's own base case is that the gravity low may be a barren, sediment-filled graben. Ranges belong to the model class, not to this project.

Commercial argument. The synthesis makes no gold-price or valuation recharacterisation, and none is offered here. Its stated commercial argument — presented as the synthesis author's view, context only, with no recovery, mining or processing cost applied and not attributed to any historical operator — is simply that the primary target is discrete and the test is small and binary: a defined geophysical feature, a single well-sited deep hole, and a clear pass/fail criterion, a profile that suits low-cost entry followed by a farm-out or joint venture once the target is confirmed.

The targets

Primary — Target 1 (EL 4909 gravity low). The known limitation is method ambiguity: the drill rationale rests principally on a single, regional-scale gravity low, because the operator interpreted the coincident magnetic and radiometric anomalies as largely cultural, and gravity alone cannot distinguish an altered intrusive body from a sediment-filled graben. The designed test resolves it in two gated steps — modern, higher-resolution gravity and density modelling to establish whether the low has the form and gradient of an intrusion or of a sediment basin, followed, only if it survives, by a single hole into a re-derived centre carried to fresh basement.

Secondary — Target 2 (EL 3681 buried magnetic pluton). An aeromagnetic interpretation of a buried pluton with a north–south dyke set beneath alluvium, never drilled; lower-maturity, requiring gravity definition and arsenic-provenance verification before it is drill-ready.

Regional vector — Lake Cowal lithocap (adjacent). An equivocal, partly-supergene advanced-argillic indication ~10–25 km off-footprint, carried as a supporting regional vector, not a target on this ground.

Testing the thesis — gates, kill criteria, cost to answer

Phase & central-case cost	Scope	Gate & kill criterion
Stage 0 — tenure (desk)	Submit Proposed Work Program; progress ELA7082 to grant. No committed field spend precedes grant.	Gate 0: grant of ELA7082. Kill: not granted, or granted on restricted terms — the play does not proceed.
Stage 1 — re-imaging  ≈A$35–70k	Recover and reprocess the 1997 airborne grids; infill ground gravity; 3D-model gravity and magnetics; recover the CSIRO Au–Mo table; datum reconciliation and provenance checks.	Gate 1: a discrete gravity feature with the form and gradient of an intrusive body, surviving modern processing. Kill: a sediment-basin form, cultural anomalies, or a feature that does not survive reprocessing — binary, and it stops the programme before any drilling cost.
Stage 2 — WF-01  drilling ≈A$160–210k (Stage 1 + WF-01 ≈A$333–520k)	Single ~400 m kill-or-confirm hole (HW-cased pre-collar through cover + HQ→NQ diamond tail) into the re-derived centre to fresh basement; JORC-2012 QAQC (CRMs, blanks, duplicates, umpire checks); SWIR/HyLogger and gyro survey.	Gate 2: altered, mineralised intrusive basement at the centre confirms the model. Per the drill design, the kill is “fresh, unaltered, unmineralised basement over the interpreted centre with no vectoring signal — an outcome the staged design accepts and prices in.” Either result is decisive.
Stage 3 — conditional	WF-02 (Target 1 step-out) and/or WF-03 (Target 2), only on encouraging WF-01. Not costed here.	No committed spend unless WF-01 intersects the system. First deep hole is a candidate for NSW cooperative-drilling co-funding (New Frontiers; CMEP round ~Sep 2026).

Every failure mode is paired with a cheap, pre-specified test: the graben-versus-intrusion question — the single largest risk — is answered for ≈A$35–70k at Stage 1, before any drilling is committed. A negative Stage 2 does not zero the ground so much as re-frame it to the conservative sediment-basin case.

Technical Manager: Dr Tim McConachy FAusIMM (1974), Senior Fellow SEG, former Rio Tinto Chief Geologist.

Data room (under NDA): technical synthesis v4.1, Phase 1 drill programme design, source register and figure set.

Contact: Doug Alcock, Managing Director, CAADIA Metals Pty Ltd — dalcock@caadiametals.com.au

No JORC (2012) Mineral Resource, Ore Reserve or Exploration Target is declared or implied. Historical results are compiled from GSNSW open-file (DIGS) records, have not been verified by a Competent Person for public reporting, and are provided for context only. The IRGS / distal-replacement interpretation is a working hypothesis under test; alternative interpretations of the geophysical data exist. Earn-in terms are indicative and non-binding, subject to contract, due diligence and grant of the Exploration Licence.