Scorpio Gold’s Manhattan Project: Grade Strength vs Resource Risk

Scorpio Gold’s pitch rests on a single number that cuts both ways. The Manhattan Project in Nevada carries a 1.26 g/t Au inferred grade, roughly double the 0.5 g/t Au norm for a Nevada open-pit oxide mine. That figure is either the most compelling data point in the company’s investment case or the one most likely to be misread.

The context makes the question timely. Scorpio Gold listed its American Depositary Shares (ADS) on the NASDAQ Capital Market under the ticker SGLD on 1 September 2026, with a market capitalisation of roughly US$74 million as of 17 September 2026. The listing brought new visibility, but the debut event is not the investment question.

The real question is whether the Manhattan asset justifies a valuation thesis at that market cap. What follows is a grounded technical read of the four factors that either validate or complicate the case management is making, and the single structural constraint that limits how far the thesis can travel in its current form.

Why 1.26 g/t Au matters more than the headline ounce count

Start with the baseline, because the grade number means nothing in isolation. Operating Nevada open-pit gold mines run on grades that would look thin to anyone unfamiliar with heap-leach economics.

Provenance Gold’s 2026 economic model pegs the typical Nevada open-pit operating grade at around 0.5 g/t Au, with cut-off grades as low as 0.1 to 0.2 g/t. SSR Mining’s Marigold mine, one of the state’s larger producers, carries probable reserves of 2.9 Moz Au at 0.50 g/t. That is the water level these operations swim in.

Against that baseline, Manhattan’s maiden mineral resource estimate reports 18.343 Mt at 1.26 g/t Au for approximately 740,000 ounces in the inferred category, using a 0.3 g/t cut-off. The grade is roughly double the Nevada norm, which is management’s benchmark and one the mine-level disclosures broadly support.

The premium is not a marketing invention. It is a geological outcome. Manhattan is a low-sulphidation epithermal system sitting adjacent to the Manhattan caldera, a structural setting that concentrates gold into faulted and brecciated host rock rather than spreading it thinly across bulk disseminated tonnage. That is why the grade sits above the disseminated norm.

Where 1.26 g/t Au sits on the economic scale Junior Mining Intelligence classifies open-pit grades of 1.5-3 g/t Au as “good” economic grade for modern open-pits, with anything below 0.5 g/t Au generally sub-economic outside very large bulk-tonnage operations. Manhattan’s 1.26 g/t Au inferred grade sits in the economically attractive intermediate range.

There is a separate historical, non-compliant resource of roughly 304,000 oz at 5.89 g/t Au across other parts of the package, which hints at higher-grade potential beyond the current estimate. Management has also flagged that the overall grade may dilute somewhat as the resource expands. That is normal in a growth phase, not a red flag, but it is a variable worth tracking.

The read for you is straightforward. The grade premium over Nevada norms is real and analytically meaningful, but its value depends entirely on whether it survives the move from inferred to indicated category, and that conversion has not happened yet.

What 4,780 hectares actually means for the investment case

Here is the constraint most district-scale pitches gloss over. Drilling at Manhattan has been confined to a corridor of roughly 2 km. The full land package spans approximately 4,780 hectares, stretching about 8.5 km along trend in places.

The Manhattan Central core resource covers around 1.8 km of strike length within that active focus area. Set the numbers side by side and the scale of what remains untested becomes concrete: the vast majority of the package has not been drilled under the current program.

The company has identified five historic resources along the broader package, characterised by significant grade and bulk tonnage, none of which sit in the current compliant estimate. Alongside them are peripheral targets that give a sense of what the untested ground might hold:

Nevada caldera-hosted gold projects have produced a consistent pattern in recent exploration cycles: initial resource estimates in a caldera margin setting tend to expand materially as infill and step-out drilling tests the broader structural envelope, which makes the resource growth trajectory at comparable Nevada projects a useful reference for calibrating what the Manhattan 2 Moz conceptual target might realistically require in terms of drilling density and time.

• Black Mammoth, the first peripheral historic resource outside the core zone, which returned encouraging drill results but has been constrained by permitting requirements
• A previously unrecognised mineralised volcanics opportunity identified during exploration, including an interval of 2.56 g/t Au over 13.38 m in caldera volcanic units
• Four further historic resource areas within the caldera-related epithermal setting

Black Mammoth is the clearest near-term test of whether the district-scale thesis converts from conceptual to drill-confirmed. Management expects permitting progress to allow that drilling to advance.

The Round Mountain geological link: shared caldera, not just shared zip code

The Round Mountain connection is where the district story earns geological credibility rather than resting on a map. Kinross’s Round Mountain mine sits roughly 10 miles south of Manhattan, and management characterises the two deposits as occupying opposite ends of a shared caldera structure.

That is a specific geological claim, not proximity marketing. USGS mapping of the Southern Toquima Range places the principal gold mineralising event at around 16 million years ago, along the margin of the older Manhattan caldera. The host rock strengthens the parallel: Manhattan’s mineralisation sits in ash and lapilli tuffs, while Round Mountain hosts its gold in porphyritic rhyolite and similar volcanic units.

The endowment reference is what gives the comparison weight. Round Mountain has produced more than 15 million ounces historically, and Kinross’s Phase X underground target delivered an initial mineral reserve of approximately 1.2 Moz Au eq, per the company’s Form 6-K filed 18 February 2026. Across its portfolio, Kinross added 700,000 oz to reserves in 2025, with Round Mountain contributing significantly.

The takeaway for you is a matter of framing. The Round Mountain relationship gives the district-scale thesis a real geological foundation, but you should treat the 4,780-hectare package as an option, not an asset, until drilling outside the 2-km corridor returns resource-quality intercepts.

The reprocessing opportunity: capital optionality or complexity risk?

The economic logic of reprocessing historic mine waste is genuinely compelling, and it starts with a simple fact: the hard part is already done. Prior operators mined Manhattan by open-pit from 1980 to 1989 and ran heap-leach operations from 1989 to 1993, leaving leach pads, waste dumps, and low-grade stockpiles behind.

Management describes the result as a “substantial accumulation of already-mined material sitting at surface.” That characterisation matters because material already dug and crushed changes the cost structure entirely.

The cost advantage management cites for Manhattan’s historic leach pads follows the same logic that makes tailings reprocessing economics compelling across the broader mining sector: stripping, crushing, and materials handling costs are already sunk, which compresses the capital requirement for early cash flow relative to a greenfield operation of equivalent grade.

Management’s framing of the opportunity The historic material represents “a substantial accumulation of already-mined material sitting at surface” that could offer a lower-capital route to early production.

The sequential logic runs as follows:

1. Material has already been mined and crushed by prior operators
2. Stripping and primary crushing costs are largely eliminated
3. Existing site infrastructure, including permitting, water rights, and tailings facilities, has been retained
4. Toll milling offers a potential near-term revenue route, contingent on nearby milling capacity
5. Grade data from the sonic drilling program feeds directly into preliminary economic assessment (PEA) planning

There is a working template for this in Nevada. Lahontan Gold Corp’s Santa Fe Mine placed 3.76 Mt at 0.55 g/t Au and 2.9 g/t Ag onto heap-leach pads historically, and sonic drilling reportedly shows residual grades averaging 0.50 g/t Au and 3.3 g/t Ag, with cyanide-extractable gold at roughly 40 to 43% of fire assay values. That comparable is Perplexity-sourced and has not been independently verified, so treat it as illustrative rather than confirmed.

What NI 43-101 prevents management from saying, and why that matters

Here is the frustration for anyone trying to size this opportunity: the company cannot tell you the one thing you most want to know. NI 43-101 disclosure standards prohibit publishing a volumetric estimate for the historic material without corresponding grade data.

That is a regulatory constraint, not an evasion. Until the sonic drilling delivers grade figures, the company is legally barred from putting a number on how much recoverable gold sits in those piles.

The sonic drilling program exists precisely to supply that grade data and unlock compliant disclosure. Reprocessing in Nevada is also treated as a new mining project, requiring a reclamation permit and a water pollution control permit, which adds process before any material moves.

The read for you is one of calibration. The reprocessing program is best understood as a capital-cost reduction mechanism in the PEA planning phase, not a near-term production commitment. If the grade results land, they become a material disclosure event. Until then, this is optionality, not a confirmed value driver.

The inferred-resource ceiling: where the thesis stalls without more drilling

Every pillar covered so far runs into the same wall. Manhattan’s entire 740,000-ounce resource sits in the inferred category, the lowest-confidence tier in the NI 43-101 framework.

An inferred resource is defined from limited sampling where geological continuity is estimated rather than confirmed. That distinction has hard consequences: inferred tonnes cannot be included in mineral reserve estimates, and they cannot underpin pre-feasibility or feasibility-level economic analysis. In practical terms, they cannot yet support a bankable mine plan.

The NI 43-101 framework applies the same tiered confidence logic as inferred resource classification under JORC, where limited sampling establishes geological continuity by estimation rather than confirmation, and that shared architecture explains why the ceiling on inferred tonnes applies whether a project sits in Nevada or Western Australia.

SRK Consulting warns that many PEAs lean too heavily on the assumption that inferred material will convert to indicated, and cautions that inferred resources are too speculative geologically to have economic considerations applied at all. Industry commentators have proposed rough thresholds for how much inferred material a study can safely carry:

• Junior Mining Pro suggests that if more than 20% of a PEA production schedule relies on inferred material, those tonnes cannot support feasibility-level reserves (Perplexity-sourced, unverified)
• The Mineralis blog flags that if more than 40% of life-of-mine production tonnage is inferred, later studies typically strip out a significant portion, shortening mine life and reducing net present value (Perplexity-sourced, unverified)

Both benchmarks point the same direction: a resource entirely in the inferred category has a defined ceiling until drilling upgrades it.

The company is targeting resource growth toward roughly 2 million ounces, but that is a conceptual exploration target, not a declared resource. The maiden estimate also notes that ounces from drilling since the prior period are not yet reflected, and two or more drill rigs were operating at the time of management’s commentary, with work planned into 2026. Resource growth is actively happening; the question is what confidence category it lands in.

Three structural risks apply to any inferred-heavy junior:

• Geological conversion uncertainty, since inferred tonnes may not survive infill drilling at the assumed grade or continuity
• Capital requirement growth as studies advance and the true development cost comes into focus
• The gap between a headline PEA NPV and a bankable feasibility NPV once inferred tonnes are stripped out or upgraded

The read for you is unsentimental. Every dollar of valuation above the current 740,000-ounce inferred base is being priced on exploration upside and conceptual targets. That means you are betting on conversion, and the bet has a timeline: the next resource update.

Three variables that determine whether the Manhattan thesis delivers

The four pillars collapse into a simple truth about pricing. At a US$74.08 million market capitalisation and an ADS price of US$4.28 as of 17 September 2026, the market is already valuing Scorpio Gold well beyond its 740,000 confirmed inferred ounces.

The framing that matters most for entry A US$74 million market cap against 740,000 inferred ounces means the market is pricing a story that has not fully materialised. That is what makes the next 12 months of drilling and disclosure the investment decision, not the listing event that preceded it.

Rather than a verdict, here is a monitoring framework built on three observable variables:

1. Grade retention. Does the 1.26 g/t Au grade hold as the resource expands toward the conceptual 2 Moz target, or does dilution pull it back toward the Nevada norm? Retention near current levels validates the core economic premise.
2. Sonic drilling grade results. Do the reprocessing grades reach economic thresholds, unlocking compliant disclosure and a lower-capital production pathway? Economic grades would convert this from optionality to a real value driver.
3. Inferred-to-indicated conversion. Does the next mineral resource estimate upgrade enough material to support a credible PEA? A meaningful conversion rate is what lifts the ceiling described above.

The district context remains supportive in the background. Round Mountain’s Phase X reserve of roughly 1.2 Moz Au eq confirms the broader area is still delivering mineralisation, which keeps the exploration call option alive.

The next resource update and the sonic drilling results are the two near-term binary events. Watch those, and you are positioned to size and time exposure on evidence rather than narrative.

For investors wanting to apply a systematic filter beyond the three variables outlined above, our dedicated guide to gold mining stock selection framework covers the margin, resource quality, and management track record criteria that separate durable positions from momentum-driven exploration stories at any point in the gold price cycle.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions.

Past performance does not guarantee future results. Financial projections and exploration targets are subject to market conditions and various risk factors, and forward-looking statements are speculative and subject to change based on drilling results and company performance.