# I-80’s Granite Creek resources triple, costs jump Canonical Atlas analysis: https://atlas-extractions.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--59de6987-96f8-4a26-9bc0-6a76c91b5270 Original source: https://www.northernminer.com/news/i-80s-granite-creek-resources-triple-costs-jump/1003895031/ Publisher: northernminer Original announcement: 2026-09-22T14:37:44.000Z Analysis by Minestarters Atlas Atlas analysis published: Unknown date Atlas analysis updated: Unknown date - Company: i-80 Gold - Ticker: IAU - Exchange: Unavailable - Region: Nevada - Primary commodity: Gold - Secondary commodities: None reported - Document categories: Resource update, Economic study - Extracted: 2026-09-22 14:49:29 UTC Narrative sentiment: 0.10 · Bullish ## Minestarters Atlas summary i-80 Gold has released a new feasibility study for the Granite Creek underground mine in Nevada, reporting a 229% increase in measured and indicated resources to 859,500 oz and the establishment of 556,500 oz of initial reserves. However, the study highlights a significant increase in life-of-mine AISC to $2,273/oz, up from $1,597/oz in the previous PEA. Reasoning: The announcement delivers a major resource expansion and reserve establishment via a new feasibility study, but the economic profile is tempered by a significant jump in life-of-mine AISC. - Positive factor: Significant resource growth \(229% increase in M&I\) - Positive factor: Establishment of initial reserves - Positive factor: Improved metallurgical recovery \(87% vs 78%\) - Positive factor: Expansion of mineralized footprint - Negative factor: Sharply higher AISC \($2,273 vs $1,597 in PEA\) - Negative factor: NPV sensitivity shows value erosion at higher gold prices compared to prior study - Negative factor: Elevated costs weighting the economics Facts used in scoring: 3 ## Classification and evidence **PFS Complete** Polarity: positive Definition: AACE Class 3 study complete. Why it applies: The document describes a new feasibility study which, in the context of the project stage, serves as the primary economic update. Evidence · text > a new feasibility study also shows sharply higher costs than last year’s preliminary assessment **Category Upgrade** Polarity: positive Definition: Resource confidence improved — Inferred upgraded to Indicated, or Indicated to Measured. De-risking signal. Why it applies: The study establishes initial reserves and lifts measured and indicated resources significantly. Evidence · text > It also establishes initial reserves of 556,500 oz. and lifts measured and indicated resources 229% to 859,500 ounces. **Tonnage Growth** Polarity: positive Definition: Tonnage increase reaching the strong tier vs prior estimate, with grade maintained or improved. Why it applies: Measured and indicated resources increased by 229% compared to the previous PEA. Evidence · text > lifts measured and indicated resources 229% to 859,500 ounces **Grade Decline** Polarity: negative Definition: Average grade fell below the red-flag bound vs prior estimate — deposit economics worsening. May indicate high-grading in early drilling. Why it applies: While not explicitly stated as a decline, the massive tonnage growth relative to metal growth suggests dilution or lower grade expansion, though the headline grade remains high. Evidence · text > lifts measured and indicated resources 229% to 859,500 ounces ## Extracted facts Stored fact records: 3. Some facts used in scoring do not have a stored record. ## Resource Estimates (3) ### probable [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--59de6987-96f8-4a26-9bc0-6a76c91b5270#fact-resource-facts-0) Granite Creek · gold #### Identity - Project: Granite Creek - Commodity: gold - Region: usa\_nv - Reported Region: Nevada - Ticker: IAU #### Resource scope - Estimate type: reserve - Resource group id: resource:469f995a576a3676ad2e - Mining method: combined #### Resource Data - Category: probable - Tonnes: 2200000 - Grade: 7.87 - Grade Unit: g/t - Contained Metal: 556500 - Contained Unit: oz #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-22T00:00:00.000Z Reasoning: First formal reserve declaration for the project. - Positive factor: Establishes initial reserves Evidence · text > The study establishes an initial 2.2 million proven and probable tonnes grading 7.87 grams gold per tonne for 556,500 oz. contained gold. #### Tags used in scoring **Probable Reserve** Polarity: positive Definition: Indicated Resource with demonstrated economic viability after applying modifying factors. Why it applies: category is "probable" **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 **No QP/CP Disclosure** Polarity: negative Definition: No Qualified Person or Competent Person named — lower credibility for the estimate. A QP/CP should be a member of a recognized professional association with relevant experience. Why it applies: no Qualified or Competent Person is named anywhere in the release **PEA-Supporting** Polarity: neutral Definition: Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study. Why it applies: the release names the study this estimate supports **DFS-Supporting** Polarity: neutral Definition: 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 ### indicated [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--59de6987-96f8-4a26-9bc0-6a76c91b5270#fact-resource-facts-1) Granite Creek · gold #### Identity - Project: Granite Creek - Commodity: gold - Region: usa\_nv - Reported Region: Nevada - Ticker: IAU #### Resource scope - Estimate type: resource - Resource group id: resource:cbd567dd6c98d0618cdf - Mining method: combined #### Resource Data - Category: indicated - Tonnes: 3730000 - Grade: 7.17 - Grade Unit: g/t - Contained Metal: 859500 - Contained Unit: oz #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-22T00:00:00.000Z Reasoning: Significant increase in M&I resource scale. - Positive factor: Substantial resource growth Evidence · text > Granite Creek now hosts 3.73 million measured and indicated tonnes grading 7.17 grams gold per tonne for 859,500 oz., up 229% from the PEA #### 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 **No QP/CP Disclosure** Polarity: negative Definition: No Qualified Person or Competent Person named — lower credibility for the estimate. A QP/CP should be a member of a recognized professional association with relevant experience. Why it applies: no Qualified or Competent Person is named anywhere in the release **PEA-Supporting** Polarity: neutral Definition: Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study. Why it applies: the release names the study this estimate supports **DFS-Supporting** Polarity: neutral Definition: 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 ### inferred [Link to this fact](https://atlas-extractions.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--59de6987-96f8-4a26-9bc0-6a76c91b5270#fact-resource-facts-2) Granite Creek · gold #### Identity - Project: Granite Creek - Commodity: gold - Region: usa\_nv - Reported Region: Nevada - Ticker: IAU #### Resource scope - Estimate type: resource - Resource group id: resource:fd35a0011067b49a6251 - Mining method: combined #### Resource Data - Category: inferred - Tonnes: 893000 - Grade: 7.06 - Grade Unit: g/t - Contained Metal: 202800 - Contained Unit: oz #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-22T00:00:00.000Z Reasoning: Inferred resource is present but smaller than before due to conversion to higher confidence categories. - Positive factor: Maintains high grade in inferred category - Negative factor: Inferred ounces declined due to conversion Evidence · text > while 893,000 inferred tonnes grade 7.06 grams for 202,800 ounces. #### 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 **No QP/CP Disclosure** Polarity: negative Definition: No Qualified Person or Competent Person named — lower credibility for the estimate. A QP/CP should be a member of a recognized professional association with relevant experience. Why it applies: no Qualified or Competent Person is named anywhere in the release **PEA-Supporting** Polarity: neutral Definition: Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study. Why it applies: the release names the study this estimate supports **DFS-Supporting** Polarity: neutral Definition: 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 ## 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.