# ATAC Announces Updated Resource Estimate for the Osiris Deposit, Yukon Canonical Atlas analysis: https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30 Original source: https://money.tmx.com/en/quote/ATC/news/5779435500023434/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon Publisher: tmx Original announcement: 2022-07-28T12:00:00.000Z Analysis by Minestarters Atlas Atlas analysis published: Unknown date Atlas analysis updated: Unknown date - Company: ATAC Resources Ltd. - Ticker: ATC - Exchange: TSX - Region: Yukon - Primary commodity: Gold - Secondary commodities: None reported - Document categories: Resource update, Metallurgy - Extracted: 2026-08-24 23:11:52 UTC Narrative sentiment: 0.80 · Bullish ## Minestarters Atlas summary ATAC Resources has announced an updated Mineral Resource Estimate for its Osiris Deposit in Yukon, reporting 732,000 ounces of gold in the Indicated category and 1,044,000 ounces in the Inferred category. This update includes the conversion of 43% of the 2018 Inferred Resource to Indicated, demonstrating increased confidence in the deposit. Metallurgical testwork confirms high gold recoveries, although the Carlin-style ore requires pre-treatment. Reasoning: The updated resource estimate for the Osiris Deposit shows significant conversion of Inferred to Indicated resources, increasing confidence and demonstrating overall contained gold growth. Comprehensive metallurgical testwork confirms high gold recoveries, although the ore requires pre-treatment due to its refractory nature. - Positive factor: Category Upgrade - Positive factor: Contained Metal Growth - Positive factor: QP/CP Signed - Positive factor: NI 43-101 Compliant - Positive factor: Cut-off Disclosed - Positive factor: High Recovery - Positive factor: Multi-Domain Tested - Negative factor: Refractory Ore - Negative factor: High Acid Consumption Facts used in scoring: 11 ## 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: 43% of the 2018 Inferred Resource was converted to Indicated category, significantly improving resource confidence. Evidence · text > Conversion of 43% of the 2018 maiden Inferred Resource \(1,685,000 ounces at 4.23 g/t\) to the Indicated category **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: Steven Ristorcelli, C.P.G., associate of MDA, is the Qualified Person for the Mineral Resource estimate. Evidence · text > The Qualified Person is Steven Ristorcelli, C.P.G., associate of MDA. **NI 43-101 Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with NI 43-101 \(Canada\) — high reporting standard. Why it applies: The Mineral Resource estimate was prepared using CIM definition standards, which are compliant with NI 43-101. Evidence · text > CIM definition standards were used for the Mineral Resource. **Cut-off Disclosed** Polarity: positive Definition: Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison. Why it applies: Cut-off grades for both open-pit and underground resources are clearly stated in the resource tables. Evidence · table > 1.0 Context: 4,658,000 **Resource Update** Polarity: neutral Definition: Revised estimate for an existing resource — compare to prior to assess progress. Why it applies: This announcement provides an updated Mineral Resource Estimate for the Osiris Deposit, building upon a previously released 2018 estimate. Evidence · text > ATAC Announces Updated Resource Estimate for the Osiris Deposit, Yukon **High Recovery** Polarity: positive Definition: Recovery at or above the exceptional band for the commodity and processing route. Why it applies: Metallurgical testwork confirms gold recoveries greater than 80%, with specific tests achieving up to 92% recovery. Evidence · text > Metallurgical testwork confirms >80% gold recoveries **Refractory Ore** Polarity: negative Definition: Ore requires oxidation/pressure treatment before recovery — a processing and recovery risk. Why it applies: The ore requires pre-treatment by either pressure oxidation or roasting before cyanide leaching, indicating complex mineralogy. Evidence · text > pre-treatment by either pressure oxidation or roasting, and cyanide leaching. **Multi-Domain Tested** Polarity: positive Definition: Variability across ore domains \(oxide, transition, fresh\) has been addressed. Why it applies: Geometallurgical variability testing included 147 samples analyzed from across the resource to assess characteristics. Evidence · text > geometallurgical variability testing, with 147 samples analyzed from across the resource **High Acid Consumption** Polarity: negative Story-specific tag Definition: No canonical definition is currently available. Why it applies: Acid pressure oxidation testwork incurred high acid consumption due to elevated carbonate content in the feed material. Evidence · text > the elevated carbonate content of the feed material incurs a high acid consumption. ## Extracted facts Stored fact records: 11. Some facts used in scoring do not have a stored record. ## Resource Estimates (11) ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-0) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Resource Data - Category: indicated - Tonnes: 4658000 - Grade: 4.03 - Grade Unit: g/t - Contained Metal: 604000 - Contained Unit: ounces - Cutoff Grade: 1 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: This Indicated Open-Pit resource represents a significant portion of the upgraded resource, contributing to increased confidence and overall contained gold. - Positive factor: Indicated Resource - Positive factor: Category Upgrade - Positive factor: Contained Metal Growth Evidence · table > 4.03 Context: 4,658,000 ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-1) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Resource Data - Category: indicated - Tonnes: 870400 - Grade: 4.58 - Grade Unit: g/t - Contained Metal: 128000 - Contained Unit: ounces - Cutoff Grade: 2 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: This Indicated Underground resource contributes to the overall resource upgrade and demonstrates potential for higher-grade selective mining. - Positive factor: Indicated Resource - Positive factor: Category Upgrade Evidence · table > 4.58 Context: 870,400 ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-2) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Resource Data - Category: indicated - Tonnes: 5528400 - Grade: 4.12 - Grade Unit: g/t - Contained Metal: 732000 - Contained Unit: ounces #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: The total Indicated resource represents a significant increase in confidence and contained gold, resulting from the conversion of Inferred resources. - Positive factor: Indicated Resource - Positive factor: Category Upgrade - Positive factor: Contained Metal Growth Evidence · table > 4.12 Context: 5,528,400 ### inferred [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-3) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Resource Data - Category: inferred - Tonnes: 5370000 - Grade: 3.07 - Grade Unit: g/t - Contained Metal: 530000 - Contained Unit: ounces - Cutoff Grade: 1 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: This Inferred Open-Pit resource provides future exploration potential but has lower geological confidence compared to Indicated resources. - Negative factor: Inferred Resource Evidence · table > 3.07 Context: 5,370,000 ### inferred [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-4) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Resource Data - Category: inferred - Tonnes: 3990000 - Grade: 4.01 - Grade Unit: g/t - Contained Metal: 514000 - Contained Unit: ounces - Cutoff Grade: 2 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: This Inferred Underground resource indicates potential for future high-grade zones but requires further drilling to improve confidence. - Negative factor: Inferred Resource Evidence · table > 4.01 Context: 3,990,000 ### inferred [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-5) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Resource Data - Category: inferred - Tonnes: 9360000 - Grade: 3.47 - Grade Unit: g/t - Contained Metal: 1044000 - Contained Unit: ounces #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: The total Inferred resource provides significant exploration upside but requires further work to upgrade to higher confidence categories. - Positive factor: Contained Metal Growth - Negative factor: Inferred Resource Evidence · table > 3.47 Context: 9,360,000 ### Fact 7 [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-6) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: Metallurgical testwork confirms gold recoveries greater than 80% for the Carlin-style ore, indicating a viable processing path despite requiring pre-treatment. - Positive factor: High Recovery - Positive factor: Multi-Domain Tested - Negative factor: Refractory Ore Evidence · text > Metallurgical testwork confirms >80% gold recoveries ### Fact 8 [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-7) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: Roasting of arsenic flotation tailings achieved high gold recoveries of up to 86.5%, confirming an effective pre-treatment option for the refractory ore. - Positive factor: High Recovery - Negative factor: Refractory Ore Evidence · text > recoveries of up to 86.5% for roasting ### Fact 9 [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-8) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: Alkaline pressure oxidation of arsenic flotation tailings achieved high gold recoveries of 85%, providing another viable pre-treatment option for the refractory ore. - Positive factor: High Recovery - Negative factor: Refractory Ore Evidence · text > 85% for alkaline pressure oxidation after cyanide leaching ### Fact 10 [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-9) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: Projected overall metallurgical recoveries of 83% for the combined flowsheet indicate a robust processing solution for the gold mineralization. - Positive factor: High Recovery - Negative factor: Refractory Ore Evidence · text > Projected overall metallurgical recoveries for combined flotation, oxidation and leaching are 83% ### Fact 11 [Link to this fact](https://atlas-staging.minestarters.com/news/atac-announces-updated-resource-estimate-for-the-osiris-deposit-yukon--96eb9684-f45c-4b58-871c-8e83a1ff5a30#fact-resource-facts-10) Osiris Deposit · gold #### Identity - Project: Osiris Deposit - Commodity: gold - Region: canada\_yt - Reported Region: Yukon - Ticker: ATC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2022-07-28T00:00:00.000Z Reasoning: Acid pressure oxidation achieved very high gold recoveries of 92%, but the high acid consumption due to carbonate content presents an economic challenge. - Positive factor: High Recovery - Negative factor: Refractory Ore - Negative factor: High Acid Consumption Evidence · text > Acid pressure oxidation testwork was also successful in liberating gold, with up to 92% recovery after cyanidation. ## 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.