Indicated Resource: 1.21M oz Au averaging 9.1 g/t Au
Inferred Resource: 3.94M oz Au averaging 8.4 g/t Au
Highlights
- Windfall mineral resource estimate expanded to world-class scale
- Mineral resource estimate entirely above 1200 metres vertical depth
- 2019 drilling increased indicated mineral resource estimate by 60% (added 452,000 ounces) and increased inferred mineral resource estimate by 66% (added 1,572,000 ounces)
- Osisko’s Lynx discovery hosts average grade of >10 g/t Au and the majority of indicated and inferred mineral resource estimate; significant high-grade zones (Lynx 4, Triple Lynx) remain open down plunge, 19 drills continue with infill and expansion drilling in 2020
Table 1: Windfall Gold Deposit Mineral Resource Estimate Sensitivity Table | ||||||
Cut-off | Indicated | Inferred | ||||
Tonnes (1) (000 t) | Grade (g/t) | Ounces Au (1) (000 oz) | Tonnes (1) (000 t) | Grade (g/t) | Ounces Au (1) (000 oz) | |
5.00 g/t | 2,792 | 11.4 | 1,026 | 9,495 | 10.7 | 3,258 |
4.50 g/t | 3,150 | 10.7 | 1,081 | 10,844 | 9.9 | 3,464 |
4.00 g/t | 3,586 | 9.9 | 1,141 | 12,566 | 9.2 | 3,701 |
3.50 g/t | 4,127 | 9.1 | 1,206 | 14,532 | 8.4 | 3,938 |
3.00 g/t | 4,773 | 8.3 | 1,274 | 17,213 | 7.6 | 4,218 |
Notes: | 1 Values are rounded to nearest thousand which may cause apparent discrepancies. |
Table 2: Windfall Gold Deposit Mineral Resource Estimate by Area (3.5 g/t Au cut-off) | ||||||
Area | Indicated | Inferred | ||||
Tonnes (000 t) (1) | Grade (g/t) | Ounces Au (1) (000 oz) | Tonnes (1) (000 t) | Grade (g/t) | Ounces Au (1) (000 oz) | |
Lynx2 | 1,817 | 11.3 | 661 | 6,349 | 10.9 | 2,233 |
Underdog | 561 | 8.0 | 145 | 4,776 | 6.9 | 1,067 |
Main3 | 1,749 | 7.1 | 401 | 3,407 | 5.8 | 638 |
Total | 4,127 | 9.1 | 1,206 | 14,532 | 8.4 | 3,938 |
Notes: | 1 Values are rounded to nearest thousand which may cause apparent discrepancies. |
2 Lynx area includes: | |
3 Main area includes: Zone 27, Caribou, Mallard, Windfall Nord and F-Zones. | |
4 See Windfall Gold Deposit Mineral Resource Estimate Notes further below. |
Located in
This mineral resource estimate is the result of 2,941 drill holes (1,101,008 metres) in the resource area, including 2,280 drill holes (918,273 metres) completed by Osisko from
Drilling continues at Windfall with 19 rigs focusing on measured and indicated mineral resource conversion for the planned feasibility study. Additional drills are dedicated to exploring down plunge extensions of Lynx, exploring the nearby Fox deposit, and regional target evaluation. The exploration ramp is advancing to provide additional access for underground infill drilling, and pending permit approvals, the collection of a third bulk sample deeper in the Lynx area.
This mineral resource estimate reflects the current status of the geological interpretation supported by infill drilling, underground mapping and bulk sample results. Most mineralized envelopes in the Main zone are associated with pyritic stringers occurring near contacts between volcanic rocks and younger intrusive rocks. The Lynx mineralization zones form an extensive anastomosed network of quartz-rich and pyrite-rich veins hosted within strongly silicified volcanic rocks. This system is located on the southern limb of an open fold plunging at 40 degrees towards ENE along the Bank fault-shear zone. The resource estimation includes a total of 292 mineralization zones defined by individual wireframes with a minimum true thickness of 2.0 metres. The resource reports grade blocks inside volumes potentially mineable by underground methods at a cut-off grade of 3.5 g/t Au.
Table 3: Parameters used to estimate the underground cut-off grade for the Windfall Gold Deposit Mineral Resource Estimation | ||
Parameters | Unit | Value |
Gold Price | USD$/oz | 1,325 |
Exchange Rate | USD$/CAD$ | 1.30 |
Mill Recovery | % | 93 |
Sell Cost | C$/oz | 5 |
Royalties (NSR) | % | 2 |
C$/t milled | 100 | |
G&A Cost | C$/t milled | 30 |
Processing Cost | C$/t milled | 40 |
Transportation | C$/t milled | 2 |
Environment | C$/t milled | 4 |
Calculated Cut-off Grade | g/t Au | 3.5 |
Windfall Gold Deposit Mineral Resource Estimate Notes
- The Windfall mineral resource estimate is compliant with the
November 29, 2019 CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines (as defined below). - Resources are presented undiluted and in situ and are considered to have reasonable prospects for economic extraction. Isolated and discontinuous blocks above the stated cut-off grade are excluded from the mineral resource estimate. Must-take material, i.e. isolated blocks below cut-off grade located within a potentially mineable volume, were included in the mineral resource estimate.
- As of
January 3, 2020 , the database comprises a total of 2,941 drill holes for 1,101,008 metres of drilling in the area extent of the mineral resource estimate, of which 2,280 drill holes (918,273 metres) were completed and assayed by Osisko. The drill hole grid spacing is approximately 25 metre x 25 metre for infill drilling and larger for extension drilling. - All core assays reported by Osisko were obtained by analytical methods described below under "Quality Control and Reporting Protocols".
- Geological interpretation of the deposit is based on lithologies, mineralization style, alteration and structural features. Most mineralization envelopes are subvertical, striking NE-SW and plunging approximately 40 degrees towards the North-East. The 3D wireframing was generated in Leapfrog Geo, a modelling software, from hand selections of mineralization intervals. The mineral resource estimate includes a total of 292 tabular, sub-vertical gold-bearing domains defined by individual wireframes with a minimum true thickness of 2.0 metres.
- Assays were composited within the mineralization domains into 2.0 metres length composites. A value of 0.00125 g/t Au (¼ of the detection limit) was applied to unassayed core intervals.
- High-grade composites were capped. Cappings were determined in each area from statistical studies on groups of zones sharing similar mineralization characteristics. Cappings vary from 15 g/t Au to 130 g/t Au and are applied using a three-step capping strategy where the capping value decreases as interpolation search distances increase.
- Five (5) block models were produced using Datamine™
Studio RM Software . The models are defined by parent cell sizes of 5 metres NE, 2 meters NW and 5 metres height, and sublocked to minimum subcell sizes of 1.25 meters NE, 0.5 metres NW and 1.25 metres height. - Ordinary Kriging (OK) based interpolations were produced for each area of the Windfall gold deposit. Estimation parameters are based on composite variography analyses.
- Density values of 2.8 were applied to the mineralized zones.
- The Windfall mineral resource estimate is categorized as indicated and inferred mineral resource as follows:
- The indicated mineral resource category is manually defined and encloses areas where drill spacing is generally less than 25 metres, blocks are informed by a minimum of two drill holes, and reasonable geological and grade continuity is shown.
- The inferred mineral resource category is manually defined and encloses areas where drill spacing is less than 100 metres, blocks are informed by a minimum of two drill holes, and reasonable, but not verified, geological and grade continuity is observed.
- The indicated mineral resource category is manually defined and encloses areas where drill spacing is generally less than 25 metres, blocks are informed by a minimum of two drill holes, and reasonable geological and grade continuity is shown.
- The mineral resource is reported at 3.5 g/t Au cut-off. The cut-off grade is calculated using the following economic parameters: gold price at 1,325 US$/oz, exchange rate at
1.30 USD /CAD, 93% mill recovery; selling cost at5 C$ /oz, 2% NSR royalties, mining cost at100 C$ /t milled, G&A cost at30 C$ /t milled, processing cost at40 C$ /t, transportation cost at2 C$ /t considering mill at site, and environment cost at4 C$ /t. - Estimates use metric units (metres, tonnes and g/t). Metal contents are presented in troy ounces (metric tonne x grade / 31.10348).
Micon International Limited is not aware of any known environmental, permitting, legal, title-related, taxation, socio-political or marketing issues, or any other relevant issue, that could materially affect the mineral resource estimate.- These mineral resources are not mineral reserves as they do not have demonstrated economic viability. The quantity and grade of reported inferred mineral resources in this news release are uncertain in nature and there has been insufficient exploration to define these inferred mineral resources as indicated or measured mineral resources, and it is uncertain if further exploration will result in upgrading them to these categories.
Qualified Person
The Windfall mineral resource estimate, with an effective date of
Quality Control and Reporting Protocols
All NQ core assays reported were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at (i)
About the Windfall Gold Deposit
The Windfall gold deposit is located between
About
Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in
Cautionary Statements Regarding Estimates of Mineral Resources
This news release uses the terms measured, indicated and inferred mineral resources as a relative measure of the level of confidence in the resource estimate. Readers are cautioned that mineral resources are not mineral reserves and that the economic viability of resources that are not mineral reserves has not been demonstrated. The mineral resource estimate disclosed in this news release may be materially affected by geology, environmental, permitting, legal, title, socio-political, marketing or other relevant issues. It is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration. The mineral resource estimate is classified in accordance with the
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Source: Minière Osisko inc.
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