OSISKO WINDFALL DRILLING RETURNS 3,979 g/t Au OVER 2.3 METRES

(Toronto, October 05, 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 40 intercepts in 15 drill holes (7 from surface, 8 from underground) and 13 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 continues to deliver high-grade values. Today’s spectacular headline result includes a sub-interval of over 15 kilograms per tonne gold and is the second highest sample ever recorded at Windfall (see Osisko news release date December 1, 2020). Our resource infill and expansion drill program has continuously demonstrated the high-grade nature of the Windfall deposit.”

Selected high-grade intercepts include: 3979 g/t Au over 2.3 metres in OSK-W-21-2565; 118 g/t Au over 3.4 metres in WST-21-0763A; 110 g/t Au over 2.3 metres and 79.7 g/t Au over 2.0 metres in WST-21-0858A; 82.7 g/t Au over 2.2 metres in OSK-W-21-1949-W8; 25.6 g/t Au over 4.2 metres in OSK-W-21-2551-W3; and 35.8 g/t Au over 2.9 metres in OSK-W-21-2564-W1. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

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-21-1432-W6 879.6 881.6 2.0 8.62 LX4_3424 Lynx 4
including 879.6 880.2 0.6 28.7
OSK-W-21-1432-W7 1045.0 1047.0 2.0 13.4 LX4_3430 Lynx 4
including 1045.7 1046.4 0.7 28.4
OSK-W-21-1827-W5 877.0 879.0 2.0 5.25 UDD_4100 Underdog
OSK-W-21-1949-W8 1069.8 1072.0 2.2 82.7 32.0 LX4_3430 Lynx 4
including 1071.0 1071.6 0.6 286 100
OSK-W-21-2287-W3 1158.5 1161.5 3.0 5.00 LX4_3446 Lynx 4
OSK-W-21-2503-W5 934.0 936.0 2.0 14.6 TLX_3163 Triple Lynx
including 934.9 935.2 0.3 82.5
OSK-W-21-2544 914.0 916.5 2.5 7.51 TLX_3194 Triple Lynx
including 914.6 915.6 1.0 18.4
OSK-W-21-2551-W3 867.4 871.6 4.2 25.6 LX4_3414 Lynx 4
including 867.9 868.4 0.5 84.2
OSK-W-21-2560 349.9 352.0 2.1 9.71 Z27_1123 Zone 27
  355.0 357.0 2.0 40.1 Z27_1102 Zone 27
including 355.7 356.3 0.6 91.4
  370.1 372.5 2.4 5.09 Z27_1115 Zone 27
including 370.1 371.0 0.9 10.7
OSK-W-21-2564-W1 784.5 787.4 2.9 35.8 TLX_3159 Lynx HW
  902.0 904.0 2.0 6.70 TLX_3194 Triple Lynx
OSK-W-21-2577 797.6 799.6 2.0 5.68 Z27_1108 Zone 27
OSK-W-21-2581 257.0 259.0 2.0 5.28 CA1_2500 Caribou
including 257.4 258.0 0.6 16.5
  469.0 471.0 2.0 14.6 Z27_1115 Zone 27
  476.5 480.0 3.5 3.96 Z27_1115 Zone 27
WST-21-0763A 472.6 476.0 3.4 118 41.9 LX4_3430 Lynx 4
including 472.6 473.5 0.9 386 100
WST-21-0771C 313.4 317.0 3.6 3.90 LSW_3556 Lynx SW
including 313.4 313.8 0.4 21.4
and 316.6 317.0 0.4 12.0
WST-21-0855 172.0 174.1 2.1 18.1 LXM_3304 Lynx
including 173.8 174.1 0.3 95.3
WST-21-0858A 180.2 182.5 2.3 110 44.3 LXM_3304 Lynx
including 181.0 181.3 0.3 607 100
  517.0 519.0 2.0 79.7 28.3 LX4_3430 Lynx 4
including 518.1 518.5 0.4 357 100
WST-21-0877 305.6 307.7 2.1 4.37 Lynx SW Lynx SW
including 305.6 305.9 0.3 28.7

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below., LXM = Lynx Main, LX4 = Lynx 4, LSW = Lynx Southwest, TLX = Triple Lynx, UDD = Underdog, CA1 = Caribou, and Z27 = Zone 27.

 

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-17-841 966.3 968.8 2.5 11.2 Underdog Underdog
OSK-W-21-1432-W7 1053.0 1055.1 2.1 13.5 Lynx 4 Lynx
including 1053.0 1054.0 1.0 27.5
OSK-W-21-1827-W6 1084.0 1086.0 2.0 4.75 Underdog Underdog
including 1084.8 1085.3 0.5 18.9
OSK-W-21-1871-W1 561.7 564.2 2.5 10.8 Caribou Caribou
including 563.4 564.2 0.8 30.8
OSK-W-21-2503-W5 1004.0 1006.0 2.0 36.4 22.6 Triple Lynx Triple Lynx
including 1004.7 1005.0 0.3 193 100
OSK-W-21-2532-W1 703.0 705.1 2.1 3.50 Underdog Underdog
including 704.7 705.1 0.4 17.6
OSK-W-21-2540-W2 1149.0 1151.0 2.0 5.93 Triple Lynx Triple Lynx
OSK-W-21-2548-W1 488.0 490.0 2.0 15.9 Caribou Caribou
including 488.0 489.0 1.0 31.8
OSK-W-21-2561 611.2 613.5 2.3 9.05 Triple Lynx Triple Lynx
including 612.3 612.8 0.5 41.2
OSK-W-21-2565 535.8 538.1 2.3 3979 27.2 Caribou Caribou
including 537.5 538.1 0.6 15250 100
OSK-W-21-2577 593.0 595.0 2.0 6.61 Caribou Caribou
OSK-W-21-2581 188.4 191.0 2.6 6.65 Caribou Caribou
including 189.8 190.6 0.8 13.8
WST-21-0771C 222.0 225.2 3.2 7.83 Lynx SW Lynx SW
including 224.7 225.2 0.5 31.5
WST-21-0834B 302.0 304.0 2.0 3.54 Lynx HW Lynx HW
including 302.0 302.4 0.4 17.5
WST-21-0874 253.0 255.2 2.2 6.25 Triple Lynx Triple Lynx
WST-21-0881A 247.5 249.5 2.0 12.2 Lynx SW Lynx SW
  444.3 446.3 2.0 5.25 Lynx SW Lynx SW
including 444.8 445.2 0.4 26.1

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. HW= Hanging wall and SW = Southwest

 

Drill hole location

Hole Number Azimuth (°) Dip

(°)

Length (m) UTM E UTM N Elevation Section
OSK-W-17-841 330 -60 1032 452689 5434702 397 2800
OSK-W-21-1432-W6 132 -55 1065 453811 5435779 400 4300
OSK-W-21-1432-W7 132 -55 1185 453811 5435779 400 4300
OSK-W-21-1827-W5 331 -58 1203 452506 5434390 403 2475
OSK-W-21-1827-W6 331 -58 1281 452506 5434390 403 2475
OSK-W-21-1871-W1 331 -56 612 452496 5434397 402 2475
OSK-W-21-1949-W8 105 -57 1284 453440 5435479 401 3825
OSK-W-21-2287-W3 116 -53 1368 453607 5435714 404 4075
OSK-W-21-2503-W5 126 -58 1211 453333 5435641 413 3800
OSK-W-21-2532-W1 341 -60 1035 452480 5434428 401 2475
OSK-W-21-2540-W2 117 -60 1314 453465 5435640 410 3925
OSK-W-21-2544 128 -50 1161 452960 5435539 419 3425
OSK-W-21-2548-W1 331 -57 837 452829 5434550 398 2850
OSK-W-21-2551-W3 120 -55 954 453622 5435635 405 4050
OSK-W-21-2560 333 -53 684 452404 5434674 400 2525
OSK-W-21-2561 142 -51 801 452886 5435484 409 3350
OSK-W-21-2564-W1 132 -50 1152 452960 5435539 419 3425
OSK-W-21-2565 136 -57 717 452768 5435312 406 3150
OSK-W-21-2577 325 -52 822 452829 5434550 398 2850
OSK-W-21-2581 333 -49 755 452469 5434627 403 2550
WST-21-0763A 120 -39 567 453507 5435332 -47 3800
WST-21-0771C 127 -52 357 452954 5435003 252 3175
WST-21-0834B 114 -23 378 453463 5435327 32 3775
WST-21-0855 122 -44 265 453506 5435332 -48 3800
WST-21-0858A 118 -41 643 453507 5435332 -48 3800
WST-21-0874 137 -63 403 453508 5435327 -7 3800
WST-21-0877 158 -60 490 453104 5435065 231 3325
WST-21-0881A 147 -57 457 453105 5435065 231 3325

 

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.

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.

 

Zone 27

Mineralization most commonly occurs as replacement-type characterized by 5% to 50% disseminated, stringer, semi-massive or stockwork pyrite, ptygmatic tourmaline veins, quartz-tourmaline crustiform veins, local quartz-carbonate veins, and local visible gold. Mineralization is associated with moderate to strong sericite, weak to strong silica, weak chlorite and carbonate and locally weak fuchsite and is hosted in strongly altered andesites, in or at the contact of the rhyolite, or along the contacts with felsic porphyritic intrusions.

 

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.

 

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 2,700 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

 

Long Section Expan EN 20211005

Long Section Infill EN 20211005

PR_EN_20211005_Surface

PR_EN_20211005_UG