OSISKO WINDFALL DRILLING INTERSECTS MORE HIGH-GRADE

118 g/t Au Over 2.3 Metres in Triple Lynx

96.2 g/t Au Over 2.6 Metres in Lynx 4

(Toronto, December 15, 2021) Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new analytical results from the ongoing drill program at its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec.

Significant new analytical results presented below include 35 intercepts in 14 drill holes (6 from surface, 8 from underground) and 9 wedges. The infill intercepts are located inside defined February 2021 mineral resource estimate (“MRE”) blocks (see Osisko news release dated February 17, 2021). The expansion intercepts are located outside the February 2021 MRE blocks and either expand resource wireframes or are in a defined zone or corridor but do not yet correlate to a specific wireframe.

Osisko Chief Executive Officer John Burzynski commented: “Windfall once again delivers high-grade intercepts with today’s results coming from across the deposit including from the Triple Lynx, Lynx 4, Caribou, Underdog, and F Zone areas. Targeted infill and expansion drilling will continue into 2022 to further define and expand our world-class gold deposit.”

Selected high-grade intercepts include 118 g/t Au over 2.3 metres in WST-21-0784; 96.2 g/t Au over 2.6 metres in OSK-W-21-2629; 108 g/t Au over 2.0 metres in OSK-W-21-2633; 83.5 g/t Au over 2.0 metres in WST-21-0855B; 37.8 g/t Au over 2.6 metres in OSK-W-21-2621. Maps showing hole locations and full analytical results are available at www.osiskomining.com. Maps:

Infill Drilling

Hole No. From (m) To (m) Interval (m) Au (g/t) uncut Au (g/t)         cut to 100 g/t Zone Corridor
OSK-W-21-1871-W1 963.0 965.8 2.8 12.7   UDD_4511 Underdog
OSK-W-21-1963-W9 1208.0 1210.0 2.0 9.63   LX4_3453 Lynx 4
1297.8 1299.9 2.1 10.8   LX4_3449 Lynx 4
including 1298.6 1299.1 0.5 38.5
OSK-W-21-2531-W1 1098.0 1100.0 2.0 4.88   UDD_4513 Underdog
OSK-W-21-2544-W4 794.0 796.0 2.0 5.76   TLX_3184 Triple Lynx
OSK-W-21-2551-W4 926.0 928.0 2.0 10.9   LX4_3417 Lynx 4
including 926.5 927.1 0.6 25.6
OSK-W-21-2587-W2 1150.0 1152.0 2.0 8.39   TLX_3172 Triple Lynx
including 1150.3 1150.7 0.4 39.4
OSK-W-21-2605 1284.4 1291.0 6.6 9.73   LX4_3449 Lynx 4
including 1284.4 1286.4 2.0 22.1
and 1289.9 1290.2 0.3 15.6
OSK-W-21-2621 651.1 653.5 2.4 16.6   UDD_4100 Underdog
including 652.0 653.0 1.0 39.3
  948.0 950.0 2.0 9.59   UDD_4514 Underdog
  953.0 955.0 2.0 14.2   UDD_4514 Underdog
OSK-W-21-2625-W1 803.0 806.5 3.5 5.74   LX4_3437 Lynx 4
OSK-W-21-2629 930.6 933.2 2.6 96.2 50.0 LX4_3437 Lynx 4
including 932.2 933.2 1.0 220 100
  944.0 946.1 2.1 32.2   LX4_3437 Lynx 4
including 944.3 945.1 0.8 84.0
OSK-W-21-2633 146.6 148.6 2.0 108 57.4 F11_6000 F-11
including 147.0 148.0 1.0 202 100
OSK-W-21-2636 357.0 359.3 2.3 33.6 22.3 CA1_2551 Caribou
including 358.0 358.5 0.5 152 100
WST-21-0649 704.2 706.8 2.6 3.89   LX4_3427 Lynx 4
including 704.2 704.5 0.3 10.8
756.9 759.0 2.1 22.2   LX4_3412 Lynx 4
WST-21-0784 259.8 262.1 2.3 118 57.4 TLX_3161 Triple Lynx
including 260.2 261.4 1.2 216 100
WST-21-0855B 177.2 181.3 4.1 13.6   LXM_3440 Lynx
including 178.1 178.4 0.3 31.3
  541.8 543.8 2.0 83.5 33.4 LX4_3404 Lynx 4
including 543.2 543.8 0.6 267 100
WST-21-0861 105.1 107.2 2.1 8.56   LXM_3311 Lynx
WST-21-0873 255.0 257.3 2.3 4.01   LSW_3500 Lynx SW
including 256.0 256.3 0.3 17.5
WST-21-0888 71.0 73.0 2.0 5.79   LXM_3336 Lynx
WST-21-0893 43.6 45.8 2.2 4.91   LXM_3303 Lynx
including 44.0 44.7 0.7 15.4

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. CA1 = Caribou, LX4 = Lynx 4, LXM = Lynx Main, LSW = Lynx South West, TLX = Triple Lynx, UDD = Underdog, F11 = F Zones.

 

Expansion Drilling

Hole No. From (m) To (m) Interval (m) Au (g/t) uncut Au (g/t)         cut to 100 g/t Zone Corridor
OSK-W-21-1432-W12 861.0 863.0 2.0 5.30   LX4 Lynx 4
  927.0 930.0 3.0 19.6   LX4 Lynx 4
  933.5 935.8 2.3 14.2   LX4 Lynx 4
OSK-W-21-2522-W2 767.0 769.0 2.0 6.62   LXM Lynx
OSK-W-21-2544-W4 813.9 816.2 2.3 18.8 13.5 TLX Triple Lynx
including 815.4 815.7 0.3 141 100
OSK-W-21-2587-W2 1077.0 1079.0 2.0 11.3   TLX Triple Lynx
including 1077.0 1077.8 0.8 27.1
OSK-W-21-2597 704.0 706.0 2.0 15.0   LX4 Lynx 4
including 704.5 705.0 0.5 34.7
OSK-W-21-2621 722.0 724.6 2.6 37.8 18.0 UDD Underdog
including 724.0 724.3 0.3 272 100
WST-21-0873 300.0 302.0 2.0 8.00   LSW Lynx SW
WST-21-0913 567.0 569.0 2.0 8.45   LX4 Lynx 4
including 568.1 568.5 0.4 41.5

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. LSW = Lynx South West, LXM = Lynx Main, LX4 = Lynx 4, TLX = Triple Lynx, UDD = Underdog.

 

Drill hole location

Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-21-1432-W12 132 -55 1113 453811 5435779 400 4300
OSK-W-21-1871-W1 331 -56 1119 452496 5434397 402 2475
OSK-W-21-1963-W9 123 -58 1388 453761 5435816 401 4275
OSK-W-21-2522-W2 128 -54 917 453450 5435592 411 3900
OSK-W-21-2531-W1 344 -62 1215 452566 5434415 403 2550
OSK-W-21-2544-W4 128 -50 858 452960 5435539 419 3425
OSK-W-21-2551-W4 120 -55 1026 453622 5435635 405 4050
OSK-W-21-2587-W2 127 -59 1167 453350 5435673 418 3850
OSK-W-21-2597 13 -75 861 454135 5435058 397 4225
OSK-W-21-2605 112 -55 1401 453552 5435669 408 4025
OSK-W-21-2621 344 -53 1001 452272 5434396 399 2275
OSK-W-21-2625-W1 33 -77 846 454135 5435058 396 4225
OSK-W-21-2629 114 -57 1011 453622 5435635 405 4050
OSK-W-21-2633 157 -47 189 452365 5435894 405 3100
OSK-W-21-2636 337 -52 801 452499 5434619 403 2575
WST-21-0649 136 -47 790 453258 5435211 98 3525
WST-21-0784 132 -66 361 453507 5435327 -7 3800
WST-21-0855B 118 -45 751 453507 5435333 -48 3800
WST-21-0861 139 -64 307 453106 5435066 231 3325
WST-21-0873 152 -61 507 453105 5435065 231 3325
WST-21-0888 140 -34 111 453314 5435164 124 3550
WST-21-0893 142 -24 120 453314 5435164 124 3550
WST-21-0913 138 -49 594 453322 5435236 54 3600

 

Caribou Zone

Mineralization most commonly occurs in gold-bearing pyrite stockworks as well as semi-massive pyrite replacement zones associated with phyllic alteration (sericite-pyrite ± silica) with sulphides, pyrite dominated with minor chalcopyrite and sphalerite ranging from trace to up to 20%, and local visible gold. Mineralization is hosted in rhyolites or mafic-intermediate volcanics frequently at or near faults or the contact with felsic porphyritic intrusions.

 

F-Zones

Mineralization is hosted in sheared andesites with carbonate replacement or quartz veining and occurs as quartz ± ankerite veinlets or as replacement type in shear zones and is characterised by trace to 10% pyrite with local visible gold. Alteration is dominated by sericite-fuchsite-tourmaline-pyrite.

 

Lynx Zone

Mineralization occurs as grey to translucent quartz-carbonate-pyrite-tourmaline veins and pyrite replacement zones and stockworks. Vein-type mineralization is associated with haloes of pervasive sericite-pyrite ± silica alteration and contain sulphides (predominantly pyrite with minor amounts of chalcopyrite, sphalerite, galena, arsenopyrite, and pyrrhotite) and local visible gold. Replacement mineralization is associated with strong pervasive silica-sericite-ankerite ± tourmaline alteration and contains disseminated pyrite from trace to 80% with local visible gold. Pyrite stockworks can form envelopes that reach several tens of metres thick. Fuchsite alteration is common and is spatially constrained to near the gabbros. Mineralization occurs at or near geological contacts between felsic porphyritic or fragmental intrusions and the host rhyolites or gabbros and locally can be hosted along the gabbro-rhyolite contact.

 

Underdog

Mineralization most commonly occurs in gold-bearing quartz-pyrite (± tourmaline) veins and as disseminated, stringer, semi-massive to massive pyrite with minor sphalerite, chalcopyrite and molybdenite associated with strong sericite and silica alteration. Mineralization is hosted along the intrusive contacts of a three-phase composite felsic porphyritic unit which cross-cuts felsic and mafic volcanic sequences.

 

Qualified Person

The scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Louis Grenier, M.Sc.A., P.Geo. (OGQ 800), Director of Exploration for Osisko’s Windfall gold project, who is a “qualified person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

 

Quality Control and Reporting Protocols

True width determination is estimated at 55-80% of the reported core length interval for the zone. Assays are uncut except where indicated. Intercepts occur within geological confines of major zones but have not been correlated to individual vein domains at this time. Reported intervals include minimum weighted averages of 3.5 g/t Au diluted over core lengths of at least 2.0 metres. NQ core assays were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at (i) ALS Laboratories in Val d’Or, Québec, Vancouver, British Colombia, Lima, Peru or Vientiane, Laos (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using a Four Acid Digestion-ICP-MS method at ALS Laboratories. Drill program design, Quality Assurance/Quality Control (“QA/QC”) and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

 

About the Windfall Gold Deposit

The Windfall gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The Mineral Resource Estimate (“MRE“) defined by Osisko, as disclosed in the news release dated February 17, 2021 is supported by the technical report entitled “Preliminary Economic Assessment Update for the Windfall Project” dated April 26, 2021 (that includes Windfall Mineral Resource Estimate with an effective date  of November 30, 2020), and assuming a cut-off grade of 3.50 g/t Au, comprises 521,000 tonnes at 11.3 g/t Au (189,000 ounces) in the measured mineral resource category, 5,502,000 tonnes at 9.4 g/t Au (1,668,000 ounces) in the indicated mineral resource category and 16,401,000 tonnes at 8.0 g/t Au (4,244,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in the February 17, 2021 news release are further described in the full technical report prepared by BBA Inc. in accordance with NI 43-101 and is available on SEDAR (www.sedar.com) under the Corporation’s issuer profile. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal zones: Lynx, Main Zone, and Underdog. Mineralization is generally comprised of sub-vertical zones following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres as it now includes the Triple 8 (T8) zone. The resources excluding T8 are defined from surface to a depth of 1,200 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down-plunge and at depth.

 

About Osisko Mining Inc.

Osisko is a mineral exploration company focused on the acquisition, exploration, and development of gold resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding Urban Barry area and nearby Quévillon area (over 2,600 square kilometres).

 

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. Any statement that involves predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always, using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “potential”, “feasibility”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may” or “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This news release contains the forward-looking information pertaining to, among other things: the Windfall gold deposit being one of the highest-grade resource-stage gold projects in Canada and having world-class scale; the key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in this news release; the prospects, if any, of the Windfall gold deposit; timing and ability of Osisko to file a technical report for the mineral resource estimate disclosed in this news release; the timing and ability of Osisko, if at all, to publish a feasibility study for the Windfall gold deposit; the amount and type of drilling to be completed and the timing to complete such drilling; the focus of the remaining infill drilling; the trend of grade increase; the Lynx zone remaining open to expansion down plunge; upgrading a inferred mineral resource to a measured mineral resource or indicated mineral resource category; future drilling at the Windfall gold deposit; the significance of historic exploration activities and results. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including (infill) drilling; property and royalty interests in the Windfall gold deposit; the ability of the Corporation to obtain required approvals; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

 

CONTACT INFORMATION:

John Burzynski
Chief Executive Officer
Telephone (416) 363-8653