i-80 Gold’s Granite Creek Study: One Project, Two Very Different NPVs

The same feasibility study produces an after-tax net present value of US$118 million at one gold price assumption and US$598 million at another. Neither figure is wrong. Working out which one actually matters for an investment decision is the analytical puzzle the Granite Creek study hands you.

i-80 Gold Corp (ticker: IAUX) released its inaugural feasibility study for the Granite Creek underground gold project in Nevada on 21 September 2026. The study establishes 556,500 ounces of proven and probable reserves, projects an 8.5-year mine life with steady-state output near 75,000 ounces per year from 2028, and carries a base-case NPV of US$118 million at its reserve-price gold assumption.

At gold near current spot levels, that same project math produces a value approaching US$600 million. With the metal trading in a band of roughly US$4,280 to US$4,405 per ounce through mid-to-late September 2026, the gap between those two figures is not academic.

This piece works through what the results mean in practice: where the economics have genuinely improved since the prior preliminary economic assessment, how to read the NPV spread without overstating spot-price upside, what the dual regulatory classification reveals about the study’s rigour, and why groundwater management is the operational variable most likely to determine whether the project delivers on its modelled numbers.

From resource estimate to reserve: what the upgrade actually represents

The headline is easy to misread as a simple resource increase. It is not. The Granite Creek study did something more consequential than add ounces: it converted them into a higher category of confidence and demonstrated they can be mined economically.

That distinction sits at the heart of mining valuation. A measured and indicated resource describes gold that geologists are confident exists in the ground, based on drilling density and modelling. A proven and probable reserve goes further: it is the portion of that resource that engineering work shows can be extracted profitably at a defined gold price, after accounting for mining costs, recovery rates, and cut-off grades.

The distinction between inferred, indicated, and measured sits at the core of how resource classification categories translate into bankable reserve figures; infill drilling does not create new gold, it upgrades the confidence level of gold already modelled, which is precisely what allows a reserve conversion to proceed.

The CIM Definition Standards for Mineral Reserves establish the precise criteria under which measured and indicated resources qualify for reclassification as proven and probable reserves, requiring demonstrated economic extraction at a defined price assumption with engineering-level cost inputs.

The prior PEA, published in March 2025, defined measured and indicated resources of 261,000 ounces at 10.5 g/t and inferred resources of 326,000 ounces at 13.0 g/t. Inferred material is the lowest-confidence category, based on limited drilling. The feasibility study reclassified the picture entirely.

Measured and indicated underground resources rose 229% to 859,500 ounces, while inferred resources fell 38% to 202,800 ounces. That combination is the signature of successful infill drilling: closer-spaced holes promoted lower-confidence material into higher-confidence categories, which is precisely what made the reserve conversion possible.

Why the grade decline does not erase the reserve gain

One number moved in the wrong direction. Grade fell from 10.5 g/t in the PEA’s measured and indicated resource to 7.87 g/t in the feasibility reserve. On its own, a lower grade sounds like a downgrade.

It is not, because tonnage more than compensated. A larger volume of rock at a slightly lower grade can hold more total gold than a smaller volume at a higher grade, and that is what happened here: the reserve now contains 556,500 ounces against the PEA’s 261,000 measured and indicated ounces.

Reserve grade is not the highest assay in the drill core; it is the economically relevant average after applying a cut-off. A consistent grade above 7 g/t for an underground operation remains high by global standards. For an investor weighing whether Granite Creek can attract project finance, the reserve figure, not the resource figure, is the number a lender counts. Converting over half a million ounces into the proven and probable category is what changed the project’s financing options.

How the NPV math works, and what the five-fold spread tells you

The economics rest on a straightforward cash flow engine. Understand the engine, and the NPV spread stops looking like a contradiction and starts looking like a measurement.

Production ramps from 30,000-40,000 ounces recovered in the 2026 start-up year to a steady state of roughly 75,000 ounces per year across 2028 to 2032. Over the 8.5-year mine life, the project is modelled to recover approximately 485,000 ounces at 87% metallurgical recovery, the share of gold in the ore that the processing plant actually captures. That steady-state figure is a meaningful step up from the roughly 60,000 ounces per year the prior PEA projected.

Feed that production into two different gold prices, and you get two very different valuations.

The US$2,750/oz case is the base case, and this is the point most retail commentary gets backwards. It is not a pessimistic scenario. Reserve prices are deliberately set at conservative, long-term levels because the same price drives the cut-off grade used to define the reserves in the first place. Change the reserve price, and you change which rock qualifies as ore. The base case and the reserve are internally consistent by design.

The US$4,500/oz case is a sensitivity, showing how project value behaves if gold stays near where it currently trades. The roughly five-fold jump between the two is not a flaw in the study; it is a precise reading of how leveraged Granite Creek’s apparent value is to the gold price.

There is a regulatory wrinkle worth noting. The same technical work is classified as a feasibility study under Canada’s NI 43-101 rules and as a pre-feasibility study under the US SEC’s S-K 1300 regime. That reflects a definitional difference between jurisdictions, not incomplete engineering. The underlying data is identical.

Management’s floor, not the study’s floor Ryan Snow of i-80 Gold, speaking at the Beaver Creek Precious Metals Summit, treated roughly US$4,000/oz as a near-term floor rather than a ceiling, and cited a US$6,000/oz target within an 18-to-24-month horizon, supported by central bank buying. Notably, the company’s internal models do not build in that higher price.

Here is the interpretation you should take from the spread. The proximity of the US$4,500/oz sensitivity to current spot is exactly what makes the project look compelling today. But the distance between spot and the US$2,750/oz reserve price is also what makes the valuation hostage to macro conditions no investor controls. That leverage cuts both ways, and it is the single most important thing to internalise before sizing a position.

What a feasibility study means for project financing, and how lenders read the two scenarios

Shift the lens from the project to the people who must fund it, and the same numbers land differently. A credit committee and an equity investor read this study through opposite ends of the telescope.

A feasibility study is what turns a project into a “bankable” proposition, one a lender will consider financing with debt. Reaching that threshold requires four things:

Project finance lending criteria in mining typically require a feasibility-grade study, a minimum reserve life, and economic analysis run at conservative long-term prices; the structural reason lenders anchor to the base case rather than the spot-price sensitivity is that repayment schedules must survive the cycle, not just the current price environment.

• Defined proven and probable reserves under a recognised code such as NI 43-101, JORC, or SAMREC, backed by detailed drilling and geological modelling.
• Engineering-level cost estimates, typically accurate to plus or minus 10-15%, covering mine planning, scheduling, infrastructure, and metallurgical testwork.
• Economic analysis (NPV, IRR, payback) run at conservative long-term prices, with sensitivity cases to show upside leverage.
• Demonstrated permitting and environmental feasibility, which reduces the non-technical risks lenders dislike most.

Standards bodies including the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the Society for Mining, Metallurgy & Exploration (SME), and the International Finance Corporation (IFC) define what a compliant, independently reviewed study looks like. Granite Creek’s reserve-backed status, defined mine plan, and dual-code reporting put it inside that framework.

When a lender opens the study, the eye goes straight to the US$118 million base case. That conservative figure is the anchor for any lending decision. The US$598 million sensitivity is read as an indication of upside, a gauge of how much cushion exists if gold stays strong, not as the premise on which a loan is written.

What equity investors see that credit committees do not weight

Equity investors run the numbers differently. With the US$4,500/oz sensitivity sitting close to today’s spot of roughly US$4,280-US$4,405, the project looks highly and positively levered to gold. Every step higher in the metal flows disproportionately into equity value, and that is a legitimate part of the bull case.

The macro backdrop feeds that enthusiasm. According to the World Gold Council, US$18 billion flowed into global physically backed gold ETFs in August 2026, the second-largest monthly inflow on record. Some institutional forecasts have pointed toward roughly US$4,500/oz, though these bank targets should be treated as unverified analyst views rather than confirmed guidance.

The caution seasoned mining analysts offer is worth heeding: test the valuation against prices nearer institutional consensus, not management’s most bullish outlook. The US$6,000/oz target sits well above both the bankable base case and mainstream forecasts. For deciding whether Granite Creek can raise the capital to reach construction, the US$118 million base case is the number to stress-test first, because that is where any lending conversation begins.

Groundwater and the operational gap between a study and a producing mine

A feasibility study describes what a mine could be. Turning that document into a producing operation depends on execution, and at Granite Creek the most concrete execution variable right now is water.

Elevated groundwater has been a genuine operational challenge at the site, requiring meaningful infrastructure investment over the past year. The company has two additional dewatering wells and an expanded water treatment facility currently in commissioning, built out over the prior 12 months in response to inflows encountered during development.

Groundwater is a front-loaded risk in underground mining, and that timing is what makes it matter. If water management infrastructure is undersized, or if inflow assumptions underestimate how permeable the rock is, development slows before a single tonne of ore reaches the plant. Capital intensity rises, and the payback period stretches out.

The institutional view on water risk Best-practice guidance from the International Council on Mining and Metals (ICMM) stresses integrated mine-water models, conservative inflow assumptions, and contingency planning for treatment and discharge. Case studies from SRK Consulting and Golder Associates find that the robustness of pre-production dewatering infrastructure is a reliable predictor of how consistently a mine hits its production targets.

The water question sits inside a broader ramp-up sequence that determines when steady-state economics actually arrive:

1. Commission the additional dewatering wells and expanded water treatment facility (currently underway).
2. Process ore through third-party facilities in the near term, targeting commercial production by late 2026.
3. Bring the Lone Tree autoclave and carbon-in-leach plant online, expected late 2027.
4. Reach steady-state output of roughly 75,000 ounces per year from 2028.

Here is the material gap for anyone running a serious cost analysis: no quantified dewatering cost estimates appear in the feasibility study press release. That absence is itself a data point. You can see the infrastructure being built, but you cannot yet put a number on how much it adds to the project’s capital intensity. Until the company discloses those costs, groundwater remains the primary due-diligence question standing between the study and the modelled economics.

For investors wanting to assess the scale of the challenge at Granite Creek before dewatering cost disclosures arrive, our full explainer on underground mine dewatering covers how inflow rates are modelled, what well capacity and treatment infrastructure typically cost, and how dewatering delays have historically affected mine development timelines.

What the Granite Creek study changes, and what it leaves open

Treat the synthesis as a weighing exercise rather than a verdict. The study resolved some questions decisively and left others firmly in the “watch this” column.

What it genuinely changed is significant. Granite Creek now holds reserve-backed status under NI 43-101, an engineering-level mine plan, and a defined production profile. That combination moves it from a speculative development asset into a bankable project capable of attracting project finance. The 556,500-ounce reserve and the 8.5-year mine plan are locked in, and they will not move with the gold price.

Nevada mining capital efficiency arguments rest partly on the state’s established infrastructure, permitting precedents, and water rights frameworks, all of which affect how quickly a project like Granite Creek can move from bankable study to construction decision.

What remains open is equally clear:

• Undisclosed dewatering costs, which prevent any firm read on true capital intensity.
• The Cove underground feasibility study, now guided to Q4 2026 after slipping from Q3.
• The Lone Tree autoclave commissioning, expected late 2027, which is the processing bottleneck governing when steady-state economics actually materialise.

Then there is the gold price itself. The five-fold NPV spread is a direct function of where gold sits relative to the US$2,750/oz reserve price. With the metal trading around US$4,280-US$4,405 in late September 2026, after declining roughly 3.9% in September following its August surge, the upside case looks close at hand. But an investor who forms a view on gold’s trajectory is, in effect, also forming a view on Granite Creek’s valuation.

The pipeline context: Cove, Lone Tree, and Archimedes

Granite Creek is the first completed study in a wider Nevada portfolio. The Cove feasibility is due in Q4 2026, the Lone Tree autoclave in late 2027, and both the Archimedes feasibility study and the Mineral Point pre-feasibility study target roughly mid-2027.

Anyone evaluating i-80 Gold as a whole will need to weight this first milestone against a still-loaded study schedule. Granite Creek shows the company can deliver a bankable study; the remaining pipeline is where the rest of the thesis will be tested.

The distinction that matters most for your own assessment is between what is settled and what is not. The reserve base, the mine plan, and the bankability threshold are resolved. The five-fold upside and management’s long-term target are gold-price-dependent. Investors who hold those two categories apart can evaluate Granite Creek on its own merits rather than as a leveraged bet on the metal.

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 are subject to market conditions and various risk factors, and forward-looking statements regarding gold prices, production, and commissioning timelines are speculative and subject to change based on market developments and company performance.