# i-80 Gold Announces Positive Feasibility Study and Initial Mineral Reserves for Granite Creek Underground; After-Tax NPV\(5%\) of $118 Million at $2,750/oz Au Increasing to $598 Million at $4,500/oz Au Canonical Atlas analysis: https://atlas-extractions.minestarters.com/news/i-80-gold-announces-positive-feasibility-study-and-initial-mineral-reserves-for--4a6d054b-7de5-452d-a03f-f17cbfe461fa Original source: https://orestocks.com/company/IAU.TO/press-releases/5816897245739500 Publisher: orestocks Original announcement: 2026-09-21T22:48:00.000Z Analysis by Minestarters Atlas Atlas analysis published: Unknown date Atlas analysis updated: Unknown date - Company: i-80 Gold Corp. - Ticker: IAU.TO - Exchange: Unavailable - Region: Nevada, USA - Primary commodity: Gold - Secondary commodities: None reported - Document categories: Resource update, Economic study, Metallurgy - Extracted: 2026-09-22 00:04:45 UTC Narrative sentiment: 0.80 · Bullish ## Minestarters Atlas summary i-80 Gold announced a positive Feasibility Study for its Granite Creek Underground gold project in Nevada, outlining an after-tax NPV\(5%\) of $118 million at a base case gold price of $2,750/oz. The study establishes initial Proven and Probable Mineral Reserves of 556,500 oz Au at 7.87 g/t Au and significantly increases Measured and Indicated resources by 229% to 859,500 oz Au. The project, which is already ramping up production, benefits from an optimized processing strategy utilizing the company's Lone Tree autoclave and CIL plant, leading to lower operating costs and an estimated LOM AISC of $2,273/oz Au \(excluding refurbishment capital\). Reasoning: i-80 Gold announced a positive Feasibility Study for its Granite Creek Underground project, outlining robust economics with an after-tax NPV\(5%\) of $118 million at a base case gold price of $2,750/oz. The study establishes initial Proven and Probable Mineral Reserves of 556,500 oz Au and significantly increases Measured and Indicated resources by 229%. The optimized processing strategy, utilizing the company's Lone Tree Plant, is expected to reduce costs and increase production. The project is fully permitted and already in production ramp-up. - Positive factor: Positive Feasibility Study results with robust economics - Positive factor: Significant increase in Measured and Indicated resources - Positive factor: Initial Proven and Probable Mineral Reserves established - Positive factor: Optimized processing strategy with lower costs at Lone Tree Plant - Positive factor: Fully permitted and operating mine ramping up production - Negative factor: S-K 1300 classification as PFS despite NI 43-101 FS - Negative factor: Reliance on third-party processing until Lone Tree Plant commissioning - Negative factor: Historical drill results for CX Zone lack QA/QC data Facts used in scoring: 8 ## Classification and evidence **DFS Bankable** Polarity: positive Definition: AACE Class 2-1 study complete and within the staleness window. Why it applies: The document states that the NI 43-101 technical report constitutes a feasibility study, indicating a high level of engineering and cost estimation maturity. Evidence · text > a technical report prepared under National Instrument 43-101 – Standards of Disclosure for Mineral Projects \("NI 43-101"\) which, in the opinion of the qualified persons, constitutes a feasibility study under NI 43-101 \(the "NI 43-101 FS" or the "FS"\) **PEA Only** Polarity: neutral Definition: Only Class 4 / Initial Assessment economics available. Not bankable. Why it applies: The S-K 1300 technical report is classified as a Pre-Feasibility Study, which is equivalent to a PEA under this regime. Evidence · text > a technical report summary prepared under Subpart 1300 of Regulation S-K \("S-K 1300"\) which, in the opinion of the qualified persons, constitutes a pre-feasibility study under S-K 1300 \(the "S-K 1300 PFS"\) **High IRR** Polarity: positive Definition: Post-tax real unlevered IRR in the strong tier or better. Why it applies: The after-tax NPV\(5%\) of $118 million at $2,750/oz Au and $598 million at $4,500/oz Au indicates a robust project with strong returns, although IRR is not explicitly stated. Evidence · text > After-Tax NPV\(5%\) of $118 Million at $2,750/oz Au Increasing to $598 Million at $4,500/oz Au **Long Reserve Life** Polarity: positive Definition: Reserve life index in the top tier of the single ladder. Why it applies: The mine life is approximately 8.5 years, which is within the adequate range for reserve life. Evidence · table > 8.5 Context: Mine Life **Bottom Quartile Cost** Polarity: positive Definition: P0-25 of the relevant commodity cost curve. Why it applies: The LOM AISC of $2,273/oz Au \(excluding Lone Tree Refurbishment Capital\) is competitive for gold production. Evidence · table > $2,273 Context: All-in Sustaining Costs - LOM\(4,5\) \(Excl. Lone Tree Refurbishment Capital\) **Conservative Pricing** Polarity: positive Definition: Conservative on the worst of the spot, 3-year and consensus comparisons. Why it applies: The base case gold price of $2,750/oz is below the illustrative spot price sensitivity of $4,500/oz, suggesting a conservative approach. Evidence · table > $2,750 Context: Gold Price **Fully Permitted** Polarity: positive Definition: Key permits granted with no unresolved challenge. Why it applies: The Granite Creek Underground mine is stated to be fully permitted. Evidence · text > The Granite Creek Underground mine is fully permitted. **Proven Reserve** Polarity: positive Definition: Measured Resource with demonstrated economic viability after applying modifying factors. Why it applies: The study reports Proven Mineral Reserves of 80,600 oz Au. Evidence · table > 80.6 Context: Total **Probable Reserve** Polarity: positive Definition: Indicated Resource with demonstrated economic viability after applying modifying factors. Why it applies: The study reports Probable Mineral Reserves of 475,900 oz Au. Evidence · table > 475.9 Context: Total **Measured Resource** Polarity: positive Definition: Highest confidence category — tonnage, grade, shape well-established from closely-spaced drilling. Basis for Proven Reserves. Why it applies: The study reports Measured Mineral Resources of 145,900 oz Au. Evidence · table > 145.9 Context: Total **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: The study reports Indicated Mineral Resources of 713,600 oz Au. Evidence · table > 713.6 Context: Total **Inferred Resource** Polarity: negative Definition: Speculative category — limited drilling, geological continuity assumed but not confirmed. Cannot support economic studies alone. Why it applies: The study reports Inferred Mineral Resources of 202,800 oz Au. Evidence · table > 202.8 Context: Total **Category Upgrade** Polarity: positive Definition: Resource confidence improved — Inferred upgraded to Indicated, or Indicated to Measured. De-risking signal. Why it applies: Measured and Indicated underground Mineral Resources increased by 229%, and Inferred Mineral Resources decreased by 38% as material was converted into higher classification categories. Evidence · text > Measured and Indicated underground Mineral Resources increased by 229% to 3.73 Mt grading 7.17 g/t Au containing 859,500 oz Au, compared to the PEA\(1\); Inferred Mineral Resources decreased by 38% to 0.89 Mt grading 7.06 g/t Au containing 202,800 oz Au as the infill program converted a portion of Inferred Mineral Resources into the higher classification categories. **Contained Metal Growth** Polarity: positive Definition: True scale improvement — contained metal ounces/tonnes increased vs prior, accounting for both tonnage and grade changes. Why it applies: Approximately 65,000 ounces have been added to mineral inventory compared to the PEA, after accounting for mining depletion. Evidence · text > approximately 65,000 ounces have been added to mineral inventory \(see Figures 1 and 2\). **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: Mineral Reserves were estimated by Anton Chan, P.Eng, MMSAQP, and Mineral Resources by Benjamin Parsons, MAusIMM \(CP\), both Qualified Persons under NI 43-101 and S-K 1300. Evidence · text > The Mineral Reserves were estimated by Anton Chan, B.Eng, M.Sc., P.Eng, MMSAQP\(\#01546QP\) of SRKConsulting, U.S. \(Inc.\), a Qualified Person under NI 43-101 and S-K 1300. **NI 43-101 Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with NI 43-101 \(Canada\) — high reporting standard. Why it applies: The technical report is prepared under National Instrument 43-101. Evidence · text > a technical report prepared under National Instrument 43-101 – Standards of Disclosure for Mineral Projects \("NI 43-101"\) **Refractory Ore** Polarity: negative Story-specific tag Definition: Ore requires oxidation/pressure treatment before recovery — a processing and recovery risk. Why it applies: Metallurgical testing demonstrated that the ore contains predominantly single refractory material requiring oxidation. Evidence · text > Metallurgical testing has demonstrated that the Ogee, Otto and South Pacific zones at Granite Creek Underground contain predominantly single refractory material and require an oxidation process to increase gold extraction using cyanidation. **Mill Route** Polarity: neutral Story-specific tag Definition: Processing via mill or concentrator \(CIL, CIP, tank leach, flotation\). Why it applies: The processing strategy involves the Lone Tree autoclave and carbon-in-leach \(CIL\) plant. Evidence · text > Lone Tree autoclave and carbon-in-leach plant **POX/BIOX Route** Polarity: neutral Story-specific tag Definition: Pressure or bio-oxidation for refractory ore — high CAPEX and OPEX. Why it applies: The ore requires an oxidation process, specifically acid pressure oxidation \(POX\) conditions. Evidence · text > acidic autoclave environment achieved higher sulfide oxidation and superior gold recovery rates. These results confirm that the Project's ore can be processed via the Lone Tree Plant's acid pressure oxidation \("POX"\) conditions **Cut-off Disclosed** Polarity: positive Definition: Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison. Why it applies: A current resource fact retains the disclosed cut-off grade **Resource Update** Polarity: neutral Definition: Revised estimate for an existing resource — compare to prior to assess progress. Why it applies: The source explicitly discloses a revised resource estimate Evidence · text > Updated Mineral Resource Estimate **Gravity Route** Polarity: neutral Definition: Gravity separation forms a material part of the flowsheet. Why it applies: the document describes a gravity route \("gravity"\) **Multi-Domain Tested** Polarity: positive Definition: Variability across ore domains \(oxide, transition, fresh\) has been addressed. Why it applies: 2 distinct composites were tested ## Extracted facts Stored fact records: 6. Some facts used in scoring do not have a stored record. ## Resource Estimates (4) ### proven [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-gold-announces-positive-feasibility-study-and-initial-mineral-reserves-for--4a6d054b-7de5-452d-a03f-f17cbfe461fa#fact-resource-facts-2) Granite Creek Underground · gold #### Identity - Project: Granite Creek Underground - Commodity: gold - Region: usa\_nv - Reported Region: Nevada, USA - Ticker: IAU.TO #### Resource scope - Estimate type: reserve - Effective date: 2026-03-31T00:00:00.000Z - Reporting standards: ni\_43\_101, sec\_sk1300 - QP Signed: Yes - Qualified person names: Anton Chan - Resource group id: resource:e321a02050188aea355d - Deposit or zone: South Pacific - Mining method: underground - Ownership percent: 100 % - Resource basis: attributable #### Resource Data - Category: proven - Tonnes: 40000 - Grade: 11.21 - Grade Unit: g/t - Contained Metal: 14.5 - Contained Unit: koz - Cutoff Grade: 4.42 - Cutoff Unit: g/t #### Prior Estimate - Resource Date: 2026-03-31 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-21T00:00:00.000Z Reasoning: The Proven Reserve of 14.5 koz Au at 11.21 g/t in the South Pacific zone represents a very high-grade component of the initial reserve estimate, indicating strong confidence in this area. The estimate is NI 43-101 and S-K 1300 compliant with QP sign-off. - Positive factor: Very high-grade Proven Reserve in the South Pacific zone - Positive factor: QP signed off on the estimate #### Tags used in scoring **Proven Reserve** Polarity: positive Definition: Measured Resource with demonstrated economic viability after applying modifying factors. Why it applies: category is "proven" **Cut-off Disclosed** Polarity: positive Definition: Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison. Why it applies: cutoff\_grade is stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **NI 43-101 Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with NI 43-101 \(Canada\) — high reporting standard. Why it applies: reporting\_standards includes ni\_43\_101 ### measured [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-gold-announces-positive-feasibility-study-and-initial-mineral-reserves-for--4a6d054b-7de5-452d-a03f-f17cbfe461fa#fact-resource-facts-3) Granite Creek Underground · gold #### Identity - Project: Granite Creek Underground - Commodity: gold - Region: usa\_nv - Reported Region: Nevada, USA - Ticker: IAU.TO #### Resource scope - Estimate type: resource - Effective date: 2026-03-31T00:00:00.000Z - Reporting standards: ni\_43\_101, sec\_sk1300 - QP Signed: Yes - Qualified person names: Benjamin Parsons - Resource group id: resource:a3f07c298becc85028ab - Deposit or zone: South Pacific - Ownership percent: 100 % - Resource basis: attributable #### Resource Data - Category: measured - Tonnes: 65000 - Grade: 9.85 - Grade Unit: g/t - Contained Metal: 20.7 - Contained Unit: koz - Cutoff Grade: 3.75 - Cutoff Unit: g/t #### Prior Estimate - Resource Date: 2026-03-31 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-21T00:00:00.000Z Reasoning: The Measured Resource of 20.7 koz Au at 9.85 g/t in the South Pacific zone represents a very high-grade component of the updated resource estimate, indicating strong confidence. The estimate is compliant with major reporting standards and has QP sign-off. - Positive factor: Very high-grade Measured Resource in the South Pacific zone - Positive factor: QP signed off on the estimate - Positive factor: Compliant with NI 43-101 and S-K 1300 reporting standards #### Tags used in scoring **Measured Resource** Polarity: positive Definition: Highest confidence category — tonnage, grade, shape well-established from closely-spaced drilling. Basis for Proven Reserves. Why it applies: category is "measured" **Cut-off Disclosed** Polarity: positive Definition: Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison. Why it applies: cutoff\_grade is stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **NI 43-101 Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with NI 43-101 \(Canada\) — high reporting standard. Why it applies: reporting\_standards includes ni\_43\_101 ### indicated [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-gold-announces-positive-feasibility-study-and-initial-mineral-reserves-for--4a6d054b-7de5-452d-a03f-f17cbfe461fa#fact-resource-facts-4) Granite Creek open pit · gold #### Identity - Project: Granite Creek open pit - Commodity: gold - Region: usa\_nv - Reported Region: Nevada, USA - Ticker: IAU.TO #### Resource scope - Estimate type: resource - Reporting standards: ni\_43\_101, sec\_sk1300 - QP Signed: Yes - Qualified person names: Benjamin Parsons - Resource group id: resource:4a9cd81151d1b965de34 - Mining method: open\_pit - Ownership percent: 100 % - Resource basis: attributable #### Resource Data - Category: indicated - Grade: 0.97 - Grade Unit: g/t - Contained Metal: 1591000 - Contained Unit: oz #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-21T00:00:00.000Z Reasoning: The updated open pit resource estimate shows a substantial Measured and Indicated resource of 1,591,000 oz Au at 0.97 g/t Au, representing an 11% increase from the prior PEA. This provides significant future potential, although it is not yet converted to reserves and requires further studies and permitting. The estimate is compliant with major reporting standards and has QP sign-off. - Positive factor: Large Measured and Indicated open pit resource of 1,591,000 oz Au - Positive factor: QP signed off on the estimate - Positive factor: Compliant with NI 43-101 and S-K 1300 reporting standards - Positive factor: Measured and Indicated resources increased by 11% compared to PEA - Negative factor: No reserves for the open pit portion - Negative factor: Still subject to ongoing technical studies and permitting activities #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **NI 43-101 Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with NI 43-101 \(Canada\) — high reporting standard. Why it applies: reporting\_standards includes ni\_43\_101 ### inferred [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-gold-announces-positive-feasibility-study-and-initial-mineral-reserves-for--4a6d054b-7de5-452d-a03f-f17cbfe461fa#fact-resource-facts-5) Granite Creek open pit · gold #### Identity - Project: Granite Creek open pit - Commodity: gold - Region: usa\_nv - Reported Region: Nevada, USA - Ticker: IAU.TO #### Resource scope - Estimate type: resource - Reporting standards: ni\_43\_101, sec\_sk1300 - QP Signed: Yes - Qualified person names: Benjamin Parsons - Resource group id: resource:b0bfd61556ad52cf8879 - Mining method: open\_pit - Ownership percent: 100 % - Resource basis: attributable #### Resource Data - Category: inferred - Grade: 0.81 - Grade Unit: g/t - Contained Metal: 99800 - Contained Unit: oz #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-21T00:00:00.000Z Reasoning: The updated open pit resource estimate includes 99,800 oz Au at 0.81 g/t Au in the Inferred category, representing a 33% increase from the prior PEA. While this indicates potential, it carries lower geological confidence and requires further work for conversion to higher categories and reserves. The estimate is compliant with major reporting standards and has QP sign-off. - Positive factor: QP signed off on the estimate - Positive factor: Compliant with NI 43-101 and S-K 1300 reporting standards - Positive factor: Inferred resources increased by 33% compared to PEA - Negative factor: Inferred category has lower geological confidence - Negative factor: No reserves for the open pit portion - Negative factor: Still subject to ongoing technical studies and permitting activities #### Tags used in scoring **Inferred Resource** Polarity: negative Definition: Speculative category — limited drilling, geological continuity assumed but not confirmed. Cannot support economic studies alone. Why it applies: category is "inferred" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **NI 43-101 Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with NI 43-101 \(Canada\) — high reporting standard. Why it applies: reporting\_standards includes ni\_43\_101 ## Metallurgical Results (2) ### metallurgical testing [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-gold-announces-positive-feasibility-study-and-initial-mineral-reserves-for--4a6d054b-7de5-452d-a03f-f17cbfe461fa#fact-metallurgical-facts-6) Granite Creek Underground · gold #### Identity - Project: Granite Creek Underground - Commodity: gold - Region: usa\_nv - Reported Region: Nevada, USA - Ticker: IAU.TO #### Test Work - Program Status: detailed - Test Type: metallurgical testing - Processing Route: acid pressure oxidation \(POX\) and carbon-in-leach \(CIL\) - Sample: Ogee, Otto and South Pacific zones #### Recovery - Recovery: 87 % - Recovery Basis: actual\_test #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-21T00:00:00.000Z Reasoning: Metallurgical testing confirmed an average gold recovery of 87% for the refractory ore from the Ogee, Otto, and South Pacific zones using an acidic autoclave environment. This is a strong recovery for refractory material and confirms the suitability of the Lone Tree Plant's POX circuit. The refractory nature of the ore is a processing challenge but is addressed by the chosen flowsheet. - Positive factor: High average gold recovery of 87% for refractory ore - Positive factor: Acidic autoclave environment achieved superior gold recovery rates - Positive factor: Processing via Lone Tree Plant's POX conditions confirmed - Negative factor: Ore is predominantly single refractory material, requiring oxidation #### Tags used in scoring **Mill Route** Polarity: neutral Definition: Processing via mill or concentrator \(CIL, CIP, tank leach, flotation\). Why it applies: processing\_route matches the mill\_cil signal **POX/BIOX Route** Polarity: neutral Definition: Pressure or bio-oxidation for refractory ore — high CAPEX and OPEX. Why it applies: processing\_route matches the pox\_biox signal ### metallurgical testing [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-gold-announces-positive-feasibility-study-and-initial-mineral-reserves-for--4a6d054b-7de5-452d-a03f-f17cbfe461fa#fact-metallurgical-facts-7) Granite Creek Underground · gold #### Identity - Project: Granite Creek Underground - Commodity: gold - Region: usa\_nv - Reported Region: Nevada, USA - Ticker: IAU.TO #### Test Work - Program Status: detailed - Test Type: metallurgical testing - Processing Route: carbon-in-leach \(CIL\) - Sample: Oxide mineralization in Ogee Zone #### Recovery - Recovery: 69 % - Recovery Basis: actual\_test - Head Grade: 10.02 - Head Grade Unit: g/t #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-21T00:00:00.000Z Reasoning: The oxide mineralization, primarily from the Ogee Zone, shows a gold payability/recovery of 69% and can be processed directly through the Lone Tree Plant's CIL circuit, bypassing the more complex POX circuit. While the recovery is lower than for refractory ore, this simplified processing route offers lower operating costs. The FS only incorporates a small component of oxide mineralization, suggesting potential for future optimization. - Positive factor: Oxide ore can be processed directly by CIL circuit, bypassing POX - Positive factor: Lower overall operating costs for oxide processing - Negative factor: Lower gold payability/recovery for oxide ore \(69%\) compared to refractory \(87%\) #### Tags used in scoring **Mill Route** Polarity: neutral Definition: Processing via mill or concentrator \(CIL, CIP, tank leach, flotation\). Why it applies: processing\_route matches the mill\_cil signal **Low Recovery** Polarity: negative Definition: Recovery below the weak band for the commodity and processing route. Why it applies: 69% is below the weak band \(80%\) ## How Atlas produces this analysis Minestarters Atlas uses automated extraction to summarize mining announcements, identify reported measurements, and classify supporting evidence. Sentiment reflects the extracted narrative and classification rules; it is an interpretation, not a reported measurement. Evidence quotes and context are provided where available. Missing data, low-confidence results, and review flags indicate limitations. Check the original publisher announcement before relying on an interpretation.