i-80 Gold Corp. (NYSE: IAUX; TSX: IAU) reported on September 21, 2026, in a release distributed via PRNewswire, the results of a feasibility study for its Granite Creek Underground gold project in northern Nevada. The study shows a mine that is bigger, longer-lived and more profitable than the company’s earlier estimate, even after more than a year of active mining depleted part of the resource base.
Highlights
- i-80 Gold Corp. (NYSE: IAUX; TSX: IAU) released a feasibility study for its Granite Creek Underground project in Nevada, reporting an initial proven and probable mineral reserve of 556,500 ounces of gold grading 7.87 grams per tonne.
- At a base-case gold price of $2,750 per ounce, the project shows an after-tax net present value of $118 million; at an illustrative $4,500 per ounce, that rises to $598 million.
- Mine life is estimated at roughly 8.5 years, with annual production of about 75,000 ounces once the company’s Lone Tree processing plant is recommissioned, expected in late 2027.
The study, supported by two technical reports, one prepared under Canada’s National Instrument 43-101 (“NI 43-101”) and one under the U.S. Securities and Exchange Commission’s Regulation S-K 1300, outlines an initial proven and probable mineral reserve of 556,500 ounces of gold across 2.2 million tonnes of ore at 7.87 g/t. Measured and indicated resources climbed 229% from the preliminary economic assessment (“PEA”) the company published in March 2025, to 3.73 million tonnes grading 7.17 g/t for 859,500 ounces. Inferred resources fell 38%, to 202,800 ounces, a sign that infill drilling upgraded much of that lower-confidence material into higher categories rather than adding entirely new ounces.
A mineral reserve differs from a mineral resource in one key way: a reserve has been shown to be economically mineable under a specific mine plan, while a resource has not yet cleared that bar and carries no such assurance.
What the Numbers Show
At the study’s base-case gold price of $2,750 an ounce, Granite Creek Underground generates $153 million in undiscounted after-tax cash flow and an after-tax net present value of $118 million, discounted at 5%. Raise the price to an illustrative $4,500 an ounce, a sensitivity case rather than a forecast, and the after-tax NPV climbs to $598 million. At $6,000, it reaches $985 million. None of those higher figures should be read as predictions of where gold is headed; they simply illustrate how leveraged the project’s economics are to the metal’s price.
Mine life now runs about 8.5 years. Once the company’s Lone Tree autoclave plant is back online, targeted for the fourth quarter of 2027, annual production should average roughly 75,000 ounces from 2028 through 2032, about 15,000 ounces a year more than the PEA projected. Cash costs for that five-year window are estimated at $1,827 an ounce, with all-in sustaining costs of $1,915 an ounce, both figures excluding the plant refurbishment spend. Sustaining capital came in lower than the PEA as well, at $83 million, despite the company adding equipment and deeper development to the plan.
Processing Plan
Until Lone Tree restarts, i-80 will keep sending ore to a third-party processor, a routine but costlier workaround for junior producers without their own mill running. The company plans to begin stockpiling ore roughly six months ahead of the plant’s commissioning so it can ramp toward full utilization as soon as it is operational.
Two Rulebooks, One Study
Because i-80 trades on both the NYSE and the TSX, it reports its technical work under two overlapping but distinct disclosure regimes. NI 43-101 and Regulation S-K 1300 use similar confidence categories, Measured, Indicated and Inferred, but apply different criteria for what qualifies as a reserve. In this case, the same underlying drilling and engineering work meets the bar for a full feasibility study under NI 43-101 but only a pre-feasibility study under S-K 1300, a distinction that reflects the two frameworks’ different rules rather than anything specific to Granite Creek itself.
Exploration Upside and a Historical Caveat
The company also flagged the CX Zone as a future exploration target. It cited two legacy high-grade intercepts, 18.0 g/t gold over 9.1 meters in hole HPR 078 and 15.3 g/t over 9.1 meters in RHC-1763, alongside a more recent i-80 hole, iGM21-06, which returned 36.4 g/t over 9.1 meters. The two legacy holes come from drilling by Homestake Mining Company in 1997 and Pinson Mining Company in 1995, predate current sampling and quality-control standards, and were not generated by i-80 itself; no QA/QC data is available for them. The company says a review by Global Resource Engineering found the historical holes acceptable for use in this year’s open-pit resource update, but they remain historical figures, not a current mineral resource, and should be read with that caveat attached. The i-80 hole, by contrast, comes from the company’s own recent drilling program.
Ongoing 2026 drilling is focused on the South Pacific, Rangefront, Otto and Ogee zones, both to fill in the current mine plan and to test for additional ounces at depth. The high-grade portion of CX Zone is slated for evaluation as part of a larger, multi-year drill program the company expects to start in 2027.
Independent Sign-Off, and Some Context
Both qualified persons behind the estimate, Benjamin Parsons and Anton Chan, work for SRK Consulting (U.S.), Inc., an outside engineering firm with no other disclosed role at i-80 Gold. For scale, Granite Creek sits adjacent to Nevada Gold Mines’ Turquoise Ridge Complex, where operator Barrick Mining Corporation has disclosed roughly 19.3 million ounces of measured and indicated gold resources of its own. i-80’s technical team has not independently verified that figure, but it underscores how mineral-rich this stretch of northern Nevada is.
What’s Next
A separate feasibility-level study for the company’s Cove underground project, previously expected earlier in the year, is now due in the fourth quarter of 2026. Granite Creek Underground itself is already producing, ramping toward an expected 30,000 to 40,000 ounces of gold output for 2026.
Sources
Editorial Disclosure
This article is based on a press release issued by i-80 Gold Corp. on September 21, 2026, and distributed via PRNewswire. Securities discussed: i-80 Gold Corp. (NYSE: IAUX | TSX: IAU). Mining Markets Report has not received compensation from i-80 Gold Corp., its management, investor relations representatives, or any third party for the creation of this specific coverage. No staff member, principal, or affiliate of Mining Markets Report holds a position, option, or interest in this security as of the publication date. Statements regarding future production, mine life, gold-price scenarios, project economics, permitting outcomes, and the timing of the Lone Tree Plant refurbishment and commissioning are forward-looking and involve risks and uncertainties; actual results may differ materially. Mineral resource and mineral reserve estimates are also subject to inherent geological and economic uncertainty; mineral resources that are not mineral reserves do not have demonstrated economic viability. Mineral exploration and development-stage mining stocks carry a high degree of financial risk. This article is published strictly for informational, news-reporting, and educational market context purposes only. It does not constitute an investment recommendation, endorsement, or professional financial, legal, or tax advice.
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