Overview
| Stage | Permitting |
| Mine Type | Underground |
| Commodities |
|
| Mining Method |
- Longhole stoping
- Longitudinal stoping
- Cemented backfill
- Paste backfill
|
| Mine Life | 10 years (as of Jan 1, 2022) |
The Windfall Project is currently one of the highest-grade undeveloped gold projects in the world.
Osisko Corporation's strategy in partnership with Gold Fields is to advance and develop the Windfall Project towards a production decision. In line with its strategy, the Corporation completed and filed the Windfall Feasibility Study on January 10, 2023 and completed an Environmental Impact Assessment for the Windfall Project on March 29, 2023. The Corporation also signed a definitive agreement with Miyuukaa Corp., a wholly-owned corporation of the Cree First Nation of Waswanipi, for the construction of a proposed transmission line facilities and the transportation of hydroelectric power to the Windfall Project. The Partnership is advancing the Windfall Project towards the permitting process while advancing detailed engineering, Impact Benefit Agreement discussions, and procurement. |
| Latest News | Osisko Windfall 2023 Drilling Update Regional Exploration to Resume October 26, 2023 |
Source:
On May 02, 2023, Osisko Mining Inc. concluded a 50/50 joint venture agreement with a subsidiary of Gold Fields Limited ("Gold Fields") for the joint ownership and development of Osisko's Windfall gold project (the "Transaction").
Transaction Details
The Transaction closed on May 2, 2023, with Gold Fields acquiring a 50% partnership interest in the "Windfall Mining Group", a partnership formed under the laws of the Province of Ontario (the "Partnership"), which will develop the Windfall project and the surrounding Urban Barry and Quévillon exploration properties (collectively, the "Property"). The Transaction was implemented in accordance with, among other things, a framework agreement dated May 2, 2023 (the "Framework Agreement") among Osisko, Gold Fields, Gold Fields Holdings Company Limited, Windfall Mining Group and 1000516419 Ontario Inc., the manager of the Partnership (the "Manager").
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Deposit Type
- Vein / narrow vein
- Replacement
Summary:
The Windfall deposit is classified as a pre-Temiskaming intrusion-associated gold deposit due to: 1) a temporal and spatial association of gold with felsic calc-alkaline QFP intrusions; and 2) the main gold event (i.e., vein- and replacement-type mineralization) being interpreted to pre-date known regional scale deformation.
Mineralization consists of a network of quartz-carbonate-pyrite-tourmaline veins and an associated silica-sericite-pyrite alteration assemblage. The mineralization and alteration have strike lengths of >2 km that show, as of yet, no recognized vertical zoning. Gold mineralization is only locally spatially associated with calc-alkaline QFP dikes but shows no genetic association with them. The QFP intrusions were emplaced mainly as a product of tectonism and deformation and act only as competent host rocks that concentrate deformation and gold-bearing hydrothermal fluids.
Mineralization
Gold mineralization in the Windfall deposit is observed in two main settings and include: 1) vein-type mineralization; and 2) replacement type mineralization.
Vein-type mineralization consists of grey to translucent coloured quartz veins that contain subordinate amounts of ankerite, tourmaline, pyrite and commonly visible gold. The veins have sharp contact margins that are straight or folded. Texturally these veins are massive, but locally can form laminated textures characteristic of fault-fill veins (Robert and Poulsen, 2001). The vei ........
Mining Methods
- Longhole stoping
- Longitudinal stoping
- Cemented backfill
- Paste backfill
Summary:
The Windfall Project mineralization varies in dip and thickness both along strike and at depth. All geometries are suitably extracted using the Longitudinal Longhole Stoping method with backfill.
The Windfall Project has three primary zones: Lynx (Lynx zone), Main and Underdog (Main zone). All zones trend roughly east-northeast and dip vertically between 45° to 90°. The Main zone is the western portion of the planned mining area and the Lynx zone is the eastern portion. The zones are accessed by three ramp systems, with two surface portals for transportation and material haulage.
Longitudinal longhole mining is suitable for the Windfall Project, where the dip of the mineralization is 45° or greater, and the materialized zones are of sufficient width and grade that the estimated dilution does not eliminate the profitable recovery of the material. Mining will consist of an undercut level and an overcut level, each accessed from the main ramp or an access drift. Each sill will be accessed perpendicularly from the ramp or access drift, and then developed along strike of the vein to the economic extents of the mineralization.
Once sill development is completed on each level, production holes are drilled between the sills and then blasted until the stoping panel is completed. Following cavity monitoring of the stope, the void is then prepared for backfill. Once a sufficient distance along strike (one to two stope lengths) has been extracted and back ........
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Flow Sheet:
Summary:
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Reserves at November 25, 2022:
The Mineral Resource is reported at 3.5 g/t Au cut-off.
The Mineral Reserve is reported a 1.7-g/t marginal cut-off grade.
| Category | Tonnage | Commodity | Grade | Contained Metal |
|
Probable
|
12,183 kt
|
Gold
|
8.06 g/t
|
3,159 koz
|
|
Probable
|
12,183 kt
|
Silver
|
4.18 g/t
|
1,639 koz
|
|
Measured
|
811 kt
|
Gold
|
11.4 g/t
|
297 koz
|
|
Measured
|
811 kt
|
Silver
|
6.7 g/t
|
174 koz
|
|
Indicated
|
10,250 kt
|
Gold
|
11.4 g/t
|
3,754 koz
|
|
Indicated
|
10,250 kt
|
Silver
|
5.9 g/t
|
1,939 koz
|
|
Measured & Indicated
|
11,061 kt
|
Gold
|
11.4 g/t
|
4,050 koz
|
|
Measured & Indicated
|
11,061 kt
|
Silver
|
5.9 g/t
|
2,110 koz
|
|
Inferred
|
12,287 kt
|
Gold
|
8.4 g/t
|
3,337 koz
|
|
Inferred
|
12,287 kt
|
Silver
|
4.8 g/t
|
1,892 koz
|
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