Hill End Goldfield (NSW) – High-Grade Gold Potential at Depth: Investment Memo
Executive Summary
Not investment advice: just an AI machine theorising
The Hill End goldfield in New South Wales is a historic high-grade, coarse-gold camp now poised for modern exploration at depth. Recent geological studies and drilling indicate that bonanza gold grades (>10 g/t Au) are not confined to the near-surface oxide zone, but continue in a subvertical corridor of mineralization well below 100 m depth. The high grades are structurally controlled by a folded turbidite sequence (the Hill End Anticline) with bedding-parallel “reef” veins and late reverse faults focusing gold into steeply plunging and gently plunging ore shoots.
Comparisons with other orogenic gold systems – notably Bendigo and Fosterville in Victoria, and Ora Banda in Western Australia – demonstrate that similar geologic architectures can sustain high-grade gold mineralization to significant depths. Hill End already hosts a JORC-compliant resource of ~225,000 oz at an average 16.7 g/t Au between 70 m and 320 m depth, and the system remains open.
Key risk factors include the coarse-gold “nugget effect” and structural complexity, which can make grade continuity and targeting challenging. However, the geological evidence and world-class analogues provide a strong rationale for continued investment in deeper drilling at Hill End.
This memo summarises the geologic framework, upside potential, analogues, risks, and provides a recommendation to fund renewed deep exploration to unlock the field’s remaining high-grade potential.
Geological Overview
Geologic Setting: The Hill End goldfield lies in the Silurian-Devonian turbidites of the Hill End Trough, deformed into a series of north–south trending folds and reverse faults. Gold is hosted mainly in the Late Silurian Chesleigh Formation – a sequence of interbedded sandstones, siltstones, and slates – on the limbs of the doubly plunging Hill End Anticline. The anticline’s eastern limb contains most of the gold, especially where it is cut by later faults. Quartz veins are generally confined to certain stratigraphic layers (carbonaceous slate beds) within the metasandstones.
Vein Systems: Multiple sets of quartz veins carry gold (see Table 1). The principal veins are bedding-parallel laminated quartz reefs that formed along favourable slate beds on the anticline limbs. These veins strike ~N–S and dip ~60° east, typically 5–30 cm thick (locally up to ~0.75 m). Up to 8 parallel veins may stack across a 100+ m stratigraphic interval on a given section, and at least 13 individual reef veins have been documented in the main Hawkins Hill–Reward area.
Classic 19th-century names for some of these veins (e.g. Paxton’s, Phillipson’s, Frenchman’s, Star of Peace, etc.) are still used. Minor “leader” veins are shallow-dipping, crack-seal quartz veinlets that radiate out from the main bedding-plane reefs. There are also steeply dipping “spur” veins and cross-course faults (west-dipping reverse faults) that cut across the bedding. Gold occurs as native (free) gold in quartz, often coarse-grained, with only minor sulphides (pyrrhotite, arsenopyrite, pyrite) and trace base metals in the primary veins. Alteration is minimal (carbonate, chlorite, sericite selvages) indicating a low-sulfide orogenic system.
Structural Controls: High-grade ore shoots are formed by the interplay of these structures. Gently north-plunging, near-horizontal shoots occur where flat “leader” veins intersect the steep bedding-parallel veins. Historically, these produced spectacular pockets of gold (the famous Holtermann Nugget came from such a shoot ~40 m below surface).
Additionally, steeply plunging ore shoots are found where the bedding-parallel veins are intersected by the later cross faults and spur veins. Kinematic studies suggest the cross-course faults had minor dextral strike-slip movement, creating local dilation zones for gold deposition. Notably, most of the bonanza gold mined at Hill End was hosted in the bedding-parallel veins on the east limb of the anticline, with only minor mineralization in the fold hinges or west limb.
In fact, unlike Victorian goldfields (Bendigo, etc.), the saddle-reef structures in the anticline core at Hill End are largely barren – meaning the limbs and fault intersections are the prime exploration targets for high-grade shoots.
Table 1 – Major Vein Sets and Structures at Hill End
| Structure / Vein Type | Orientation & Nature | Role in Gold Mineralisation |
|---|
| 1 | Bedding-Parallel “Reef” Veins | N–S strike; ~50–60° E dip; laminated quartz reefs in slate beds on anticline limbs. Individual veins 5–30 cm thick (locally up to ~0.5–0.75 m); often occur in sub-parallel stacks. | Primary gold hosts: Contain most of the high-grade gold. Coarse visible gold in quartz common. Rich shoots occur where intersected by other structures. Historical mining focused on these veins on the east limb. |
|---|
| 2 | “Leader” Veins | Shallow-dipping to horizontal quartz veinlets (crack-seal texture) branching from main reefs. Typically only a few cm thick. | Horizontal shoot formation: Where leader veins intersect bedding-parallel reefs, they form gently north-plunging high-grade shoots (10–20° plunge) that yielded bonanza pockets. These controlled many of the famous coarse-gold finds. |
|---|
| 3 | “Spur” Veins & Cross-Course Faults | Steeply dipping (generally west-dipping) reverse faults and associated quartz veins cutting across bedding. Minor strike-slip (dextral) movement noted on faults. | Vertical shoot formation: Create steeply plunging ore shoots where they intersect the bedding-parallel veins. Provided additional channel-ways for fluids, localising high-grade zones at fault-vein intersections. Also offset and repeat vein segments, increasing structural complexity. |
|---|
Sources: Geological Survey of NSW reports and Wilkins & Quayle (2021)
Mineralisation Stages: Orogenic gold at Hill End formed during multiple deformation events in the Devonian. Table 2 summarises the paragenesis and timing. Early during folding (D1, Middle Devonian), bedding-parallel veins began to develop but were mostly barren or low-sulphide (pyrrhotite–arsenopyrite) with little gold.
The main gold deposition occurred post-peak metamorphism, in later deformation phases. Radiometric dating and fluid inclusion studies indicate two main gold pulses: one around ~356 Ma and a second around ~343 Ma . These correspond to Stage III and IV in the paragenesis, when low-salinity H₂O–CO₂–CH₄ fluids at ~293–340°C were channeled into the fold structures. Gold was precipitated during these stages along with sulphides (arsenopyrite, pyrrhotite) in the quartz veins. A final stage (Stage V) introduced some late quartz–carbonate and minor hypersaline fluids (with local Sb/Pb minerals in Hawkins Hill) but with minimal gold.
Importantly, most of the gold (and sulphides) at Hill End is interpreted to have been deposited during the syn-to-late folding event (D1/Tabberabberan Orogeny) and slightly thereafter, making it a classic orogenic gold system rather than a simple supergene-enriched deposit.
Table 2 – Paragenetic Stages of Gold Mineralisation at Hill End
| Stage (Timing) | Description & Mineral Assemblage | Gold Deposition? |
|---|
| 1 | Stage I (D₁, ~370–380 Ma) | Development of early bedding-parallel veins during main folding. Quartz + chlorite ± pyrite formed; arsenopyrite–pyrrhotite dissemination in host rock. Andalusite & garnet grew in host (peak metamorphism) . Fluids were high-temperature, relatively low sulphur (indicated by pyrrhotite–arsenopyrite assemblage). | Minor – Little to no gold. (Prepared structural sites and introduced arsenic/sulphur, but gold largely stayed in solution). |
|---|
| 2 | Stage II (early D₃) | Continued vein development and minor folding of earlier veins. Possible additional quartz veinlets and sulphide introduction. | Minor – Not a major gold stage (transitional). |
|---|
| 3 | Stage III (Late D₃, ~356 Ma) | Main gold stage (Event 1). Major influx of metamorphic hydrothermal fluid as folding wanes. Low-salinity, H₂O–CO₂–CH₄ fluids ~293–340°C deposit abundant gold along with sulphides (arsenopyrite, pyrite) in quartz veins . Bulk of coarse gold in bedding-parallel reefs formed now. | Yes – Major. (Accounts for a large portion of the gold in Hill End veins) . |
|---|
| 4 | Stage IV (D₄, ~343 Ma) | Secondary gold stage (Event 2). Brittle reactivation of structures (reverse faults, spur veins) with continued metamorphic fluid flow. Quartz–carbonate veins with gold and stibnite (at depth) in some areas. High-grade pockets where new faults intersect earlier reefs. Fluid inclusion data: hypersaline, CO₂-poor fluids also present. | Yes – Minor. (Some additional gold introduced or remobilised, enhancing grade in structural intersections). |
|---|
| 5 | Stage V (Post-D₄) | Late/Post-mineral. Cooling of system. Minor carbonate, quartz, and sulphide (marcasite, trace galena-sphalerite at Hawkins Hill) deposited in veins. Supergene processes later redistributed near-surface gold. | Negligible primary gold. (Supergene enrichment later added secondary gold near surface). |
|---|
Sources: Lu & Seccombe (1993), Lu et al. (1996) fluid inclusion studies; Downes & Seccombe (2003) .
Current Resources: Modern exploration (1990s–2020s) by Hill End Gold Ltd and now Vertex Minerals Ltd has outlined a substantial high-grade resource below the old workings. The Hawkins Hill–Reward deposit has a JORC (2012) Mineral Resource of 419,000 tonnes at 16.7 g/t Au for ~225,000 oz (Indicated & Inferred, at 4 g/t cutoff). This resource spans roughly 700 m of strike along the anticline and a vertical extent of ~250 m (from ~70 m to ~320 m below surface). Fourteen (14) stacked quartz reef veins were modeled in this resource, consistent with the multiple vein sets observed underground.
Notably, no resource ounces have yet been tallied below ~320 m depth – not due to an end of mineralization, but due to limited drilling at depth. The top of the resource (70–90 m depth) corresponds to the base of oxidation; virtually all resource ounces are in fresh rock (primary zone). This is encouraging for depth potential, as discussed next.
Exploration Upside – High-Grade Continuity at Depth
Vertical Grade Distribution: A critical question for Hill End is whether the exceptional grades near surface (including supergene-enriched zones in the top ~50 m) persist with depth into the primary (unoxidised) zone.
Geological and production data indicate yes, high grades continue well beyond the oxide zone.
Historical mining in the 1870s exploited extremely rich shoots down to ~200 m depth at Hawkins Hill, recovering ~12 tonnes of gold (~386k oz) from that zone. While some of the incredible grades near surface were boosted by supergene enrichment (e.g. the Holtermann nugget ~50 m deep was a product of secondary gold reconcentration), primary mineralisation was also very high-grade.
In fact, mine records and recent analyses show that gold grades >10 g/t are restricted to a steep, north–south trending corridor that cuts through the deposit – and this high-grade corridor extends to depth on the east limb of the anticline. Outside of that structural corridor, veins at depth tend to be low grade or barren, but within it, the veins carry multi-ounce grades well below 100 m depth.
This finding (from drilling and face sampling) gives a clear target for deep exploration: follow the known high-grade structural zone down-plunge.
A long-section through Hawkins Hill–Reward illustrates that high-grade ore shoots (bonanza zones) plunge gently north and remain intact to the limits of drilling (Figure 1). These shoots are aligned with the intersection of Paxton’s vein set and a late reverse fault (the “Reward Fault”), and they have been mined on levels 640 to 695 mRL – roughly 100–150 m below surface – with excellent grades.
Below the lowest workings (~320 m depth), the structure continues but is sparsely drilled. One deep hole in 2022 intersected the extension of the system ~100 m below current resources, returning visible gold – hinting that the bonanza zone continues at depth (Vertex, pers. comm., 2024). Thus, the vertical profile of grade at Hill End does not show a cutoff at 100–200 m; instead, high grades persist into the deep primary zone, as long as the controlling structures remain present.
Only bedding-parallel veins within a specific steep N–S corridor (shaded) showed >10 g/t Au at depth, indicating a focused high-grade shoot extending well below historical stopes. Modern development (red) and historic workings (gray) are shown.
To quantify the resource distribution with depth, Table 3 segments the current resources and past production by approximate depth intervals. The data underscore that significant ounces remain in situ below the old shallow workings. The majority of the JORC resource (225 koz) lies between 100 m and 320 m depth, averaging ~15–17 g/t, which is comparable to the head grades of the 19th-century mining above. Meanwhile, virtually no drilling has tested below ~350 m, leaving that domain as an exploration target. Given the geologic continuity, there is a reasonable expectation that the high-grade shoots could persist for several hundred metres further down-plunge (as seen in analogous deposits like Bendigo/Fosterville – discussed in the next section).
Table 3 – Gold Endowment vs. Depth at Hill End (Hawkins Hill–Reward)
| Depth from Surface | Status/Workings | Estimated Grade & Ounces |
|---|
| 1 | 0–50 m (Oxide & Supergene) | Shallow stopes and shafts (1870s era). Significant supergene enrichment in places (e.g. Holtermann zone at ~40–50 m depth) . | Grades: Extremely high in pockets (100–>1,000 g/t in localized zones ). Production: Tens of thousands of oz (exact grade unknown due to selective mining, but historic accounts describe “jewelry ore”). This zone largely mined out in 19th century. |
|---|
| 2 | 50–150 m (Upper Primary) | Extensive historic mining in Hawkins Hill to ~200 m depth . Some modern development on 640 level (≈110 m depth) opening new areas. | Grades: 10–30 g/t typical in mined shoots; locally much higher (avg. ~1 oz/ton reported historically) . Production: ~386k oz historic (to 200 m) . Residual resource remains in remnant pillars. Supergene influence diminishes with depth; gold is primary. |
|---|
| 3 | 150–320 m (Lower Primary) | Below old Hawkins Hill workings; includes Reward area. Modern drilling and underground development (2007–2010) accessed this zone via the Amalgamated Adit and Reward shaft . No historic stoping (virgin ground). | Grades: 8–20 g/t in drilling and resource model (resource avg. 16.7 g/t) . Visible gold observed in core. High-grade shoots focused in ~20–50 m thick pods along structure . Resource: 419 kt @ 16.7 g/t for 225 koz (Ind + Inf) , largely within 150–320 m depth. |
|---|
| 4 | >320 m (Open at depth) | Very limited drilling to date; no mining. High-grade structure projected to continue down-plunge to north. | Grades: Unknown – exploration target. Potential: Company geologists have speculated an additional multimillion-ounce potential along the anticline below existing workings , analogous to how Fosterville discovered large high-grade reserves at 700–1000 m depth. This remains to be tested with deep drilling. |
|---|
Sources: Historic production records (Harper 1918), Hill End Gold/Vertex Minerals resource statements , Downes & Seccombe (2003)
In summary, the high-grade gold system at Hill End shows impressive vertical continuity in the controlled corridor: the grades at 300 m depth are comparable to those at 30 m depth. Given that the system is only drill-constrained – not geologically closed – at ~320 m, the exploration upside below remains substantial.
Modern underground access (the Reward shaft and drives) could be utilised to drill shorter holes targeting 300–600 m depths along the plunge of known shoots, greatly increasing the odds of intercepting more high-grade ore. The next section compares this scenario to similar orogenic gold camps where deep drilling paid off handsomely.
Comparative Analysis to Other Orogenic Gold Systems
Hill End shares many features with other “slate belt” orogenic gold systems in Australia, and these analogues illustrate the potential for high-grade continuity at depth:
• Bendigo Goldfield (Victoria): Like Hill End, Bendigo’s 19th-century mines exploited saddle-reef and leg-reef quartz veins in folded turbidites. Dozens of gently plunging high-grade shoots were mined, yielding ~22 million ounces Au historically.
Most Bendigo shoots were found within ~500 m of surface, but this was largely a limit of 19th–20th century mining technology and not necessarily the gold’s extent. Modern exploration in the 2000s (Bendigo Mining Ltd.) confirmed that some reefs (e.g. the Deborah and Sheepshead lines) persisted to ~800–1000 m depth, albeit thinner. Structural parallels: Both Bendigo and Hill End have gold localised by the intersection of bedding-parallel veins and cross structures. At Bendigo, the famous shallow-plunging “lines of reef” are analogous to Hill End’s horizontal shoots formed by leader veins.
One key difference is that Bendigo’s fold hinges (saddles) were often rich, whereas Hill End’s hinge-zone veins are sparse. Nonetheless, Bendigo’s experience shows that an orogenic system can host multiple stacked high-grade lenses vertically, requiring systematic exploration along the fold’s plunge. Hill End’s single known high-grade corridor could be just one “line” – there may be others parallel to it (as Bendigo had many lines), and it could extend much deeper.
• Fosterville Mine (Victoria): Fosterville is a particularly instructive analogue because it underwent a transformation from modest shallow production to a world-class high-grade mine at depth. Fosterville’s geologic setting is similar (folded Ordovician turbidites cut by steep reverse faults) and it lies in the same Bendigo Zone of the Lachlan Fold Belt.
Historically it produced gold from arsenopyrite-rich disseminations at ~5–7 g/t. However, between 2015–2020, drilling down-plunge discovered the Swan Zone, a faulted anticline-limb structure with extraordinary grades (average ~31 g/t) between 700–1100 m depth. The Swan Zone alone added ~589k oz @ 31.6 g/t to Fosterville’s reserves, and it remains open.
Crucially, the highest grades at Swan occurred where a west-dipping reverse fault (Swan Fault) intersected another structure (Eagle Fault). This mirrors Hill End’s situation, where the best grades are found where west-dipping faults cut the east-dipping veins. Fosterville also showed that gold can “reinvent itself” at depth – in its case, as visible gold with stibnite appearing deeper in the system.
Hill End’s mineralogy is simpler (no stibnite noted), but the lesson is that depth can bring new high-grade mineralisation styles.
The takeaway: Hill End’s geologic model – folds with cross-fault intersections – is the same recipe that produced Fosterville’s high-grade Swan Zone. It is conceivable that a “Swan-like” zone could exist at Hill End at greater depths, given the right structures and fluid history, and only drilling will tell. As one geologist put it, Fosterville’s discovery implies “never assume an old goldfield is mined out – check the plunge”.
• Ora Banda / Eastern Goldfields (Western Australia): Orogenic gold systems in the Archean greenstone belts also exhibit long-lived high-grade shoots. For example, at Ora Banda’s Riverina deposit, recent drilling extended the known lodes from 240 m to 480 m depth, with intercepts such as 2.4 m @ 26.4 g/t Au at ~320 m and 1.2 m @ 51.0 g/t at ~258 m. The Riverina veins are hosted by a shear/fold structure and were open in all directions after drilling, similar to Hill End’s situation. The company noted that mineralisation “remains open at depth” with continuity over >100 m vertical extent in high-grade shoots.
This demonstrates that even in very old (Archean) orogenic systems, depth extensions of high-grade lodes are common, not the exception.
The controlling structures (steep shear zones, fold repeats) persist to depth, and so does gold tenor. Hill End, though Paleozoic, should be no different – especially since it formed in a compressional regime with a large fluid pressure/flow (estimated 17 km³ of fluid passed through the system), suggesting the plumbing for gold went deep.
In comparing these systems, common themes emerge: an anticline or similar fold providing a primary control, secondary faults or structures localising the richest shoots, and significant down-plunge continuity of high grade where those structures persist. Bendigo and Fosterville highlight that multiple high-grade zones can exist in one fold system, and that grades can even improve at depth under the right conditions (Fosterville’s visible gold). Hill End’s geology aligns closely with the classic Victorian style – indeed it has been described as a “slate-belt gold system” of the Victorian type.
Modern analysis reclassifies it as a competency-controlled low-sulphide orogenic gold system with imbricated reverse faults, which is exactly the profile of Fosterville and parts of Bendigo. This gives confidence that Hill End’s remaining potential could be unlocked with the same persistence that yielded great results in Victoria.
One difference to note is scale: Bendigo’s entire goldfield extends over tens of kilometres and many separate shoots, whereas Hill End’s known mineralisation is concentrated in a narrower 8 km corridor. However, within that corridor, the endowment per vertical metre is very high (the Hawkins Hill area alone produced >12 t Au from ~200 m vertical). This bodes well for finding additional ounces by probing deeper – the “plunge length” of the system is not yet fully determined. In Victorian analogues, productive shoots sometimes ran for >1 km down-plunge (e.g. some Bendigo lines, and Fosterville’s Lower Phoenix system ~2 km) . Even if Hill End’s shoots were half as extensive, that could double or triple the current resource with depth.
In summary, the comparative analysis strongly suggests that Hill End’s high-grade gold is structurally and genetically analogous to larger orogenic systems where deep extensions have been successfully found. Therefore, pursuing the depth potential at Hill End is justified by precedent – the high grades can continue, and even increase, with depth in such systems.
Risk Factors and Considerations
While the geological case for deep high-grade gold at Hill End is compelling, an investment decision must weigh key risks:
• Geological Continuity vs. “Nugget Effect”: Hill End’s gold occurs largely as coarse, particulate gold in quartz. This introduces a high grade variability (nugget effect) in drill sampling and resource estimation. Local assays can exceed 1,000 g/t, but between these pockets the grade can drop off sharply over a few meters. This makes it challenging to extrapolate grades between drill holes – a risk that the actual continuity of high-grade might be less than modelled. Mitigation includes using a large number of drill data points, applying top-cuts (the resource uses a 120 g/t top-cut to avoid overestimation), and where possible doing underground bulk sampling. Investors should be aware that resource grades are an average of many extreme values; thus, production reconciliation could differ if the distribution of nuggets is unfavourable. However, this risk is inherent to most high-grade orogenic gold projects (e.g. Bendigo had similar issues) and can be managed with appropriate drilling density and geostatistics.
• Structural Complexity: The same structural intersections that create rich shoots also complicate the mine geology. Hill End’s vein system is sliced by faults that can offset or terminate individual veins. For example, minor normal faulting has been observed to offset units and veins at Hawkins Hill. If a planned drill pierce or development drive misses the narrow high-grade vein by a few metres due to an unknown fault displacement, it could lead to blank results. Detailed 3D geological modelling and understanding of the fault geometry is essential to target effectively. The 2021 study by Wilkins & Quayle provided a robust structural model (14 vein sets, numerous fault blocks), which helps reduce this risk. Still, any deep exploration will likely encounter surprises in structure that need on-the-fly model updates.
• Depth and Mining Method: As exploration moves deeper, costs rise and extraction becomes more challenging. Hill End’s current high-grade resource is within ~320 m of surface, accessible via existing adits/shafts. Going deeper (>500 m) might require shaft deepening or new decline infrastructure, which is capital intensive. Before betting on a Fosterville-scale discovery at 800+ m depth, one must consider the cost of drilling and eventually mining at those depths in an area with limited existing infrastructure. The positive side is Hill End has a head start – an underground development (the Amalgamated Adit at 640 mRL and the Reward shaft) is already in place down to ~230 m depth, which could be extended. Additionally, the deposit’s steep plunge means step-out distances are not vast (the target might be a few hundred meters north of current workings at 500 m depth). Nonetheless, the financial commitment to prove deep resources is significant.
• Resource Conversion Risk: Currently about 69% of the Hill End resource (by ounces) is in the Inferred category, reflecting limited drill density in places. Converting these to Indicated/Measured with closer-spaced drilling could downgrade some ounces if continuity isn’t as expected. The company has identified infill drilling and improved underground access as priorities. From an investment viewpoint, additional drilling might be needed not just for discovery but to firm up what’s already presumed – requiring funding before those ounces can count in reserves. There’s also a risk that some high-grade zones are so small that they can’t be reliably captured in a mine plan despite high assay grades (as seen historically at Hill End – many rich pockets were sporadic).
• Commodity and Market Risks: Gold price volatility affects project economics, especially for a high-grade narrow-vein mine that needs a certain margin to justify the intense development. Fortunately, high grades (>10 g/t) afford a cushion against moderate gold price drops. At ~17 g/t, Hill End’s resource is robust; even if diluted in mining to, say, 10 g/t, it would still be a very high-margin ore. On the flip side, the market appetite for funding junior gold exploration can ebb and flow. Investors will want to see tangible results (e.g. a few deep drill hits confirming big potential) before committing large capital. Early drilling failures could impact the share price and make further financing harder – a classic exploration risk.
• Permitting and Technical: Hill End is in a historic mining district with existing mining leases and even a small operational gravity plant on site. This reduces regulatory risk for continued exploration and development. However, any expansion (deeper shafts, increased throughput) would require updated permits. On technical processing risk: Hill End ore is free-milling (gravity recoveries ~92% reported), which is excellent, and there’s no need for cyanide in the current flow sheet. Unless the ore character changes at depth (e.g. more sulphides, but presently sulphide content is low), processing should remain straightforward. Thus, technical and environmental risks are relatively low compared to many projects, thanks to simple metallurgy and a mining-friendly locale.
In weighing these factors, the key risk-reward balance is favourable. The primary risks (nugget effect, structural complexity) are geological challenges that can be managed with careful drilling and planning – and they are outweighed by the potential reward of a major high-grade discovery. The existence of an operating plant and permit at Hill End is a de-risking factor (any new discovery could be rapidly trial-mined and processed). Ultimately, the biggest “risk” may be not exploring at all – as failing to test the depth potential could leave a significant gold endowment in the ground.
Recommendation
Investment Thesis: Hill End represents a rare combination of proven high grades, existing infrastructure, and untested depth potential in an orogenic gold system. The geological evidence indicates that high-grade gold persists well below the historic workings, concentrated along predictable structural targets. This is the same blueprint that has led to enormous success in analogous goldfields (e.g. Fosterville’s Swan Zone). With gold prices robust and a renewed industry focus on high-margin ounces, Hill End’s deep potential is a highly attractive exploration play that could materially increase the company’s resource base – potentially by multiples – if successful.
Proposed Program: It is recommended to undertake a focused deep drilling program from the underground 640 Level and/or via surface pads on the Hill End Anticline to test the down-plunge extension of the known high-grade corridor. An initial program of, say, 8–10 diamond drill holes targeting 400–600 m below surface (drilling ~200–300 m below the current resource) is justified. The goal would be to intersect the projected position of the Paxton’s and Phillipson’s vein sets and associated structures at depth, to verify that gold grades >1 oz/t continue. If even a couple of holes return multi-ounce grades over minable widths, it would confirm a new high-grade zone and add significant ounces. Additionally, some drilling along strike (northwards towards Germantown, south towards Red Hill) is warranted to search for repeats of the high-grade shoot in other parts of the 8 km corridor. The budget should also include further infill drilling of the existing resource to upgrade Inferred ounces – improving the mine development case and providing platforms for deeper drilling.
Value Uplift Potential: A successful deep drill program could outline an extension comparable to the known resource (~200–300k oz) or perhaps a much larger prize if multiple stacked shoots are found. For context, Hill End’s exploration target below the old mines has been previously conceptualised at 4–5 Moz of gold potential by company geologists. Even if only a fraction of that is realised, it would transform the project. A new high-grade discovery at depth would likely re-rate the company substantially (as happened when Fosterville hit the Swan Zone, or when Northern Star extended the Pegasus orebody at Kundana). The presence of a high-grade mill on site means any discovery can be rapidly monetised via trial mining, shortening the pathway to cash flow.
Risk Mitigation: It is recommended that this investment be staged. Phase 1 drilling should test the concept – if results confirm the model, Phase 2 can aggressively step out. Ongoing geological modeling will be crucial; a small team of structural geologists should be funded to update interpretations with each drillhole (the 3D model will guide each subsequent hole). Given the nugget effect, incorporating oriented core drilling and broader sampling methods (like whole-core assays or pilot stope trials) can help assess the true grade. The company should also maintain flexibility: if initial deep holes miss the main shoot, analyse the fault geometry and adjust targeting rather than abandoning – high-grade systems can be unforgiving if you miss by even 10 m, so an iterative approach is needed.
Conclusion: Hill End’s high-grade gold story is far from over – it is likely entering a new chapter. All the pieces (right geology, structure, metallurgy, and infrastructure) are in place for a major upside if diligent exploration is pursued. The comparatively small scale of past mining (56 tonnes Au) relative to the volume of the system and fluid flow (17 km³) hints that more gold is waiting to be found at depth. By investing in a targeted deep exploration program, VTX aims to unlock a significant increase in high-grade resources, extending the mine life and creating substantial value. The recommended strategy is to proceed with deeper drilling at Hill End. The potential reward – a multi-million-ounce high-grade discovery – justifies the risks, especially in light of strong analogues and the robust geology underpinning the system. It is a calculated risk that aligns with a focus on high-impact gold opportunities.
Recommendation: Approve continued and expanded funding for deep exploration drilling at the Hill End Reward project. The combination of demonstrated high grades >10 g/t beyond 100 m, clear structural controls, and comparisons to successful orogenic gold camps supports this investment as a high-upside opportunity. We recommend budgeting for a two-phase deep drill program and associated underground access improvements, with strict milestones and review points. The objective is to delineate additional high-grade resources at depth, thereby enhancing the overall project NPV and making Hill End a flagship high-grade asset for the company.
(20min delay)