# I-80’s Granite Creek resources triple, costs jump Canonical Atlas analysis: https://atlas-staging.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--f706788a-761f-4218-ba5c-3092fad0ee63 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: 2026-09-22T14:51:45.912Z Atlas analysis updated: 2026-09-22T14:51:45.912Z - Company: i-80 Gold - Ticker: IAU - Exchange: Unavailable - Region: Nevada - Primary commodity: Gold - Secondary commodities: None reported - Document categories: Resource update, Production - Extracted: 2026-09-22 14:51:46 UTC Narrative sentiment: 0.20 · Bullish ## Minestarters Atlas summary i-80 Gold has released a feasibility study for the Granite Creek underground mine in Nevada, reporting a 229% increase in measured and indicated resources to 859,500 ounces. While the study establishes initial reserves and improves recovery rates, it also forecasts a 42% increase in life-of-mine all-in sustaining costs compared to the previous preliminary economic assessment. Reasoning: The announcement reports a major resource expansion and reserve establishment, but these gains are offset by a significant increase in projected operating costs. - Positive factor: Significant resource growth \(229% increase in M&I\) - Positive factor: Establishment of initial reserves - Positive factor: Improved average recovery \(87% vs 78%\) - Positive factor: Expansion of mineralized zones and continuity demonstrated - Negative factor: Sharply higher life-of-mine all-in sustaining costs \(up 42%\) - Negative factor: NPV sensitivity shows lower value at higher gold prices compared to PEA - Negative factor: Elevated capital and closure costs Facts used in scoring: 3 ## Classification and evidence **Category Upgrade** Polarity: positive Definition: Resource confidence improved — Inferred upgraded to Indicated, or Indicated to Measured. De-risking signal. Why it applies: Inferred ounces declined as they were converted into higher-confidence measured and indicated categories. Evidence · text > Much of the decline in inferred ounces reflects conversion into higher-confidence categories. **Resource Update** Polarity: neutral Definition: Revised estimate for an existing resource — compare to prior to assess progress. Why it applies: The document provides a new feasibility study updating the previous preliminary economic assessment. Evidence · text > a new feasibility study also shows sharply higher costs than last year’s preliminary assessment. ## Extracted facts Stored fact records: 3. Some facts used in scoring do not have a stored record. ## Resource Estimates (3) ### proven [Link to this fact](https://atlas-staging.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--f706788a-761f-4218-ba5c-3092fad0ee63#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:11bd5df3669462e0ba47 - Deposit or zone: Granite Creek - Mining method: combined #### Resource Data - Category: proven - 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: New reserve establishment is a major project milestone. - Positive factor: Establishes initial reserves Evidence · text > establishes initial reserves of 556,500 oz. ... 2.2 million proven and probable tonnes grading 7.87 grams gold per tonne for 556,500 oz. contained gold #### 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 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-staging.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--f706788a-761f-4218-ba5c-3092fad0ee63#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:f79efc615cec97547086 - Deposit or zone: Granite Creek - 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: Substantial resource growth significantly de-risks the project. - Positive factor: 229% increase in M&I resources Evidence · text > lifts measured and indicated resources 229% to 859,500 ounces. ... 3.73 million measured and indicated tonnes grading 7.17 grams gold per tonne for 859,500 oz. #### 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-staging.minestarters.com/news/i-80-s-granite-creek-resources-triple-costs-jump--f706788a-761f-4218-ba5c-3092fad0ee63#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:0f97f965cdef348b787f - Deposit or zone: Granite Creek - 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 significant but lower confidence; decline in ounces is due to conversion to higher categories. - Positive factor: Maintains high grade in inferred category - Negative factor: Decline in inferred ounces due to conversion Evidence · text > 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.