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
Original announcement by cnw on
- Company
- i-80 Gold
- Ticker
- IAUX
- Exchange
- Unavailable
- Region
- Nevada
- Primary commodity
- Gold
- Secondary commodities
- None reported
- Document categories
- Economic study, Resource update, Metallurgy
- Extracted
- 2026-09-21 23:48:37 UTC
Analysis by Minestarters Atlas
Minestarters Atlas analysis
Summary
i-80 Gold announced positive results from a Feasibility Study for its Granite Creek Underground gold project, outlining an after-tax NPV(5%) of $118 million at a $2,750/oz gold price. The study reports initial Proven and Probable Mineral Reserves of 2.20 Mt grading 7.87 g/t Au for 556,500 oz, and a 229% increase in Measured and Indicated Resources to 3.73 Mt grading 7.17 g/t Au for 859,500 oz. The project has an 8.5-year mine life with average annual gold production of 75,000 oz (2028-2032) and LOM AISC of $2,273/oz (excluding Lone Tree refurbishment capital), supported by an optimized processing strategy at the company's Lone Tree Plant.
Reasoning: The document announces positive results from a Feasibility Study for the Granite Creek Underground gold project, including robust economics, a significant increase in Measured and Indicated resources, and an initial Mineral Reserve estimate. The study outlines a clear path to production with an optimized processing strategy. While the base case gold price is high, the overall results are very positive for the company.
Positive factors
- Positive Feasibility Study results with robust economics at base case gold price.
- Significant increase in Measured and Indicated Mineral Resources.
- Initial Mineral Reserve estimate provides a solid foundation for mine life.
- Optimized processing strategy with planned commissioning of wholly-owned Lone Tree Plant expected to reduce costs.
Negative factors
- Inferred Mineral Resources decreased, indicating conversion but also a reduction in speculative upside.
- Study relies on a gold price of $2,750/oz, which is above current spot prices, though sensitivities are provided.
Low confidence — this extraction should be reviewed alongside the original source.
Facts used in scoring: 5
Classification and evidence
DFS Bankablepositive
AACE Class 2-1 study complete and within the staleness window.
Why it applies: The document announces the results of a feasibility study prepared under NI 43-101, which constitutes a feasibility study (FS).
Evidence · text
“The results announced in this press release are supported by two technical reports prepared for Granite Creek Underground: (1) 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")”
High IRRpositive
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 is a strong economic indicator for the project.
Evidence · text
“After-Tax NPV(5%) of $118 Million at $2,750/oz Au”
Long Reserve Lifepositive
Reserve life index in the top tier of the single ladder.
Why it applies: The mine life is approximately 8.5 years, which is considered adequate.
Evidence · table
“8.5”
Context: Mine Life
QP/CP Signedpositive
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: The Mineral Reserves were estimated by Anton Chan, a Qualified Person 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 (#01546 QP ) of SRK Consulting, U.S. (Inc.), a Qualified Person under NI 43-101 and S-K 1300.”
JORC Compliantpositive
Resource estimate prepared in compliance with JORC Code (Australia) — high reporting standard.
Why it applies: The resource estimate was prepared in compliance with NI 43-101 and S-K 1300.
Evidence · text
“a Qualified Person under NI 43-101 and S-K 1300.”
NI 43-101 Compliantpositive
Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.
Why it applies: The resource estimate was prepared in compliance with NI 43-101 and S-K 1300.
Evidence · text
“a Qualified Person under NI 43-101 and S-K 1300.”
Measured Resourcepositive
Highest confidence category — tonnage, grade, shape well-established from closely-spaced drilling. Basis for Proven Reserves.
Why it applies: The resource estimate includes a Measured category.
Evidence · table
“Measured”
Context: Measured
Indicated Resourcepositive
Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves.
Why it applies: The resource estimate includes an Indicated category.
Evidence · table
“Indicated”
Context: Indicated
Proven Reservepositive
Measured Resource with demonstrated economic viability after applying modifying factors.
Why it applies: The reserve estimate includes a Proven category.
Evidence · table
“Proven”
Context: Proven
Probable Reservepositive
Indicated Resource with demonstrated economic viability after applying modifying factors.
Why it applies: The reserve estimate includes a Probable category.
Evidence · table
“Probable”
Context: Probable
Inferred Resourcenegative
Speculative category — limited drilling, geological continuity assumed but not confirmed. Cannot support economic studies alone.
Why it applies: The resource estimate includes an Inferred category.
Evidence · table
“Inferred”
Context: Inferred
Category Upgradepositive
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.”
High Recoverypositive
Recovery at or above the exceptional band for the commodity and processing route.
Why it applies: The average gold recovery is 87%, which is strong for gold processing.
Evidence · table
“87 %”
Context: Average Gold Recovery
Refractory Orenegative
Ore requires oxidation/pressure treatment before recovery — a processing and recovery risk.
Why it applies: The metallurgical testing demonstrated that the ore contains predominantly single refractory material requiring an oxidation process.
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 Routeneutral
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 Routeneutral
Pressure or bio-oxidation for refractory ore — high CAPEX and OPEX.
Why it applies: The processing involves an acid pressure oxidation (POX) process.
Evidence · text
“acid pressure oxidation ("POX") conditions”
Cut-off Disclosedpositive
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 Updateneutral
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 Routeneutral
Gravity separation forms a material part of the flowsheet.
Why it applies: the document describes a gravity route ("gravity")
Extracted facts
Stored fact records: 3. Some facts used in scoring do not have a stored record.
Resource Estimates (2)
provenGranite Creek Underground · goldTonnes: 40000Grade: 11.21Grade Unit: g/tContained Metal: 14.5Contained Unit: kozView all detailsHide details
Identity
- Project
- Granite Creek Underground
- Commodity
- gold
- Region
- usa_nv
- Reported Region
- Nevada
- Ticker
- IAUX
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:51bf406f6b1ef3faa4f2
- Deposit or zone
- South Pacific
- Mining method
- underground
- 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
Lab
- Laboratory
- SRK Consulting, U.S. (Inc.)
Review
- Needs Review
- No
- Historical
- No
Dates
- Event date
- 2026-09-21T00:00:00.000Z
Reasoning: The South Pacific zone contributes a high-grade Proven Reserve, showcasing the quality of mineralization in this area, despite a smaller tonnage.
Positive factors
- Very high-grade Proven Reserve in the South Pacific zone, indicating rich mineralization.
Tags used in scoring
Proven Reservepositive
Measured Resource with demonstrated economic viability after applying modifying factors.
Why it applies: category is "proven"
Cut-off Disclosedpositive
Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.
Why it applies: cutoff_grade is stated
QP/CP Signedpositive
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 Compliantpositive
Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.
Why it applies: reporting_standards includes ni_43_101
Resource Updateneutral
Revised estimate for an existing resource — compare to prior to assess progress.
Why it applies: the release compares against a previous estimate
PEA-Supportingneutral
Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study.
Why it applies: the release names the study this estimate supports
PFS-Supportingneutral
Resource estimate prepared to support a Pre-Feasibility Study — requires adequate M&I component.
Why it applies: the release names the study this estimate supports
DFS-Supportingneutral
Resource estimate prepared to support a Definitive Feasibility Study — requires high M&I confidence.
Why it applies: the release names the study this estimate supports
measuredGranite Creek Underground · goldTonnes: 65000Grade: 9.85Grade Unit: g/tContained Metal: 20.7Contained Unit: kozView all detailsHide details
Identity
- Project
- Granite Creek Underground
- Commodity
- gold
- Region
- usa_nv
- Reported Region
- Nevada
- Ticker
- IAUX
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:fa91e1284023c8939dca
- Deposit or zone
- South Pacific
- Mining method
- underground
- 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
Lab
- Laboratory
- SRK Consulting, U.S. (Inc.)
Review
- Needs Review
- No
- Historical
- No
Dates
- Event date
- 2026-09-21T00:00:00.000Z
Reasoning: The South Pacific zone contributes a high-grade Measured Resource, highlighting the quality of mineralization in this area with high confidence.
Positive factors
- Very high-grade Measured Resource in the South Pacific zone, indicating excellent mineralization quality.
Tags used in scoring
Measured Resourcepositive
Highest confidence category — tonnage, grade, shape well-established from closely-spaced drilling. Basis for Proven Reserves.
Why it applies: category is "measured"
Cut-off Disclosedpositive
Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.
Why it applies: cutoff_grade is stated
QP/CP Signedpositive
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 Compliantpositive
Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.
Why it applies: reporting_standards includes ni_43_101
Resource Updateneutral
Revised estimate for an existing resource — compare to prior to assess progress.
Why it applies: the release compares against a previous estimate
PEA-Supportingneutral
Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study.
Why it applies: the release names the study this estimate supports
PFS-Supportingneutral
Resource estimate prepared to support a Pre-Feasibility Study — requires adequate M&I component.
Why it applies: the release names the study this estimate supports
DFS-Supportingneutral
Resource estimate prepared to support a Definitive Feasibility Study — requires high M&I confidence.
Why it applies: the release names the study this estimate supports
Metallurgical Results (1)
autoclaveGranite Creek Underground · goldRecovery: 87 %Head Grade: 7.87Head Grade Unit: g/t AuView all detailsHide details
Identity
- Project
- Granite Creek Underground
- Commodity
- gold
- Region
- usa_nv
- Reported Region
- Nevada
- Ticker
- IAUX
Test Work
- Program Status
- detailed
- Test Type
- autoclave
- Processing Route
- acid pressure oxidation (POX) and carbon-in-leach (CIL)
Recovery
- Recovery
- 87 %
- Recovery Basis
- actual_test
- Head Grade
- 7.87
- Head Grade Unit
- g/t Au
Lab
- Laboratory
- SRK Consulting, U.S. (Inc.)
- Consultant
- SRK Consulting, U.S. (Inc.)
Review
- Needs Review
- No
- Historical
- No
Dates
- Event date
- 2026-09-21T00:00:00.000Z
Reasoning: The metallurgical results show a high average gold recovery, which is a strong positive for the project's economics. The optimized processing strategy, including the use of the Lone Tree Plant, is expected to improve cost efficiency, despite the refractory nature of the ore.
Positive factors
- High average gold recovery of 87% for the LOM, indicating efficient processing.
- Processing strategy optimized to use the company's wholly-owned Lone Tree Plant, reducing reliance on third-party processing.
Negative factors
- Ore is predominantly single refractory material, requiring an oxidation process.
Tags used in scoring
Mill Routeneutral
Processing via mill or concentrator (CIL, CIP, tank leach, flotation).
Why it applies: processing_route matches the mill_cil signal
POX/BIOX Routeneutral
Pressure or bio-oxidation for refractory ore — high CAPEX and OPEX.
Why it applies: processing_route matches the pox_biox signal
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.