OSISKO WINDFALL INFILLS AND EXPANDS WITH MORE HIGH-GRADE

243 g/t Au Over 2.8 Metres

(Toronto, May 4, 2022) 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 43 intercepts in 17 underground drill holes and 5 wedges from surface. The infill intercepts are located inside defined January 2022 mineral resource estimate (“MRE”) blocks (see Osisko news release dated January 10, 2022). The expansion intercepts are located outside the January 2022 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: “May the 4th be with you.  Today’s results continue to strengthen our confidence in the high-grade nature of Windfall. While the focus for the feasibility study remains on the Lynx areas, other areas such as Mallard, also continue to infill nicely and contribute high-grade ounces to the resource.”

Selected high-grade intercepts include: 243 g/t Au over 2.8 metres in WST-22-1016, 20.6 g/t Au over 9.5 metres in WST-22-1006-W1; 16.3 g/t Au over 7.9 metres in OSK-W-22-2587-W3; 48.4 g/t Au over 2.1 metres in WST-22-1003A; 37.9 g/t Au over 2.1 metres in WST-22-1010; 36.8 g/t Au over 2.1 metres in WST-21-0940; 38.2 g/t Au over 2.0 metres in OSK-W-21-2601-W2, 37.1 g/t Au over 2.0 meters in WST-21-0991, and 36.1 g/t Au over 2.0 metres in WST-22-1006-W2. Maps showing hole locations and full analytical results are available at www.osiskomining.com. Maps: Long Section_In EN 20220504, Long Section_Ex EN 20220504, PR_EN_20220504_Surface, PR_EN_20220504_UG.

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-21-2605-W1 1352.7 1355.1 2.4 7.53 LX4_3445 Lynx 4
including 1352.7 1353.0 0.3 19.4
OSK-W-22-2587-W3 1047.6 1055.5 7.9 16.3 TLX_3158 Lynx HW
including 1052.0 1053.0 1.0 39.9
WST-21-0708 522.3 524.4 2.1 22.9 LX4_3401 Lynx 4
including 522.3 523.0 0.7 68.4
WST-21-0892 70.0 72.1 2.1 8.41 LXM_3336 Lynx
  111.1 113.6 2.5 15.7 LXM_3359 Lynx
including 112.8 113.3 0.5 48.5
WST-21-0926 61.9 64.0 2.1 18.9 LXM_3336 Lynx
including 61.9 62.4 0.5 74.2
WST-21-0938 96.0 98.0 2.0 8.39 LXM_3371 Lynx
including 96.3 96.7 0.4 41.4
WST-21-0939A 60.3 62.5 2.2 3.81 LXM_3336 Lynx
including 60.3 60.7 0.4 17.4
WST-21-0939A 96.5 99.0 2.5 11.7 LXM_3371 Lynx
including 97.4 98.1 0.7 41.5
WST-21-0942 95.0 97.0 2.0 28.7 15.6 LXM_3371 Lynx
including 95.5 95.8 0.3 188 100
WST-21-0991 173.0 175.0 2.0 37.1 30.0 LHW_3206 Lynx
including 174.4 175.0 0.6 124 100
WST-22-1006-W1 505.5 515.0 9.5 20.6 14.8 LX4_3404 Lynx 4
including 505.5 505.8 0.3 89.6
and 507.1 507.5 0.4 240 100
and 509.1 509.4 0.3 92.8
  560.9 563.0 2.1 8.21   LX4_3430 Lynx 4
including 560.9 561.3 0.4 41.2
WST-22-1006-W2 519.4 521.4 2.0 4.30   LX4_3404 Lynx 4
including 519.4 519.8 0.4 17.6
  523.3 527.0 3.7 3.93   LX4_3404 Lynx 4
including 523.3 524.1 0.8 8.29
  582.0 584.0 2.0 36.1 30.4 LX4_3430 Lynx 4
including 582.0 582.6 0.6 119 100
WST-22-1003A 78.0 80.1 2.1 48.4 33.5 MAL_5219 Mallard
including 78.5 79.2 0.7 145 100
WST-22-1010 400.0 402.2 2.2 3.62 LX4_3410 Lynx 4
  406.0 408.0 2.0 4.35 LX4_3440 Lynx 4
WST-22-1012 529.0 531.3 2.3 12.5 LX4_3450 Lynx 4
including 529.6 530.4 0.8 35.5
WST-22-1013 147.3 152.5 5.2 9.62   TLX_3161 Triple Lynx
including 151.2 151.7 0.5 24.6
  206.5 212.8 6.3 3.54   TLX_3164 Triple Lynx
including 206.5 207.1 0.6 12.5
and 212.1 212.8 0.7 9.90
WST-22-1014 463.1 465.1 2.0 4.56 LX4_3430 Lynx 4
including 463.6 463.9 0.3 21.4
  489.7 493.3 3.6 4.30 LX4_3461 Lynx 4
  516.6 519.0 2.4 9.53 LX4_3443 Lynx 4
including 516.6 517.0 0.4 25.6

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. MAL = Mallard, LXM = Lynx Main, LX4 = Lynx 4, LHW = Lynx Hanging wall, and TLX = Triple Lynx.

 

 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-21-2601-W2 1296.2 1298.2 2.0 38.2 LX4 Lynx 4
including 1296.6 1297.2 0.6 100
OSK-W-22-2605-W2 1329.8 1335.0 5.2 6.56 LX4_3462 Lynx 4
including 1331.7 1332.3 0.6 28.9
  1374.0 1376.0 2.0 10.7 LX4_3445 Lynx 4
  1407.3 1409.9 2.6 17.4 LX4 Lynx 4
including 1408.5 1409.4 0.9 46.9
OSK-W-22-2605-W3 1433.9 1436.3 2.4 4.74 LX4 Lynx 4
WST-21-0939A 113.8 115.8 2.0 13.1 LXM_3359 Lynx
including 113.8 114.5 0.7 30.1
WST-21-0940 111.0 113.1 2.1 36.8 30.9 LXM_3359 Lynx
including 112.5 113.1 0.6 121 100
WST-21-0941 115.2 117.3 2.1 14.4 LXM_3359 Lynx
including 115.2 115.6 0.4 75.1
WST-21-0946 175.0 177.2 2.2 26.0 18.3 TLX_3161 Triple Lynx
including 176.8 177.2 0.4 143 100
WST-22-1003A 95.4 97.5 2.1 9.97 MAL Mallard
including 97.1 97.5 0.4 34.9
  166.1 169.6 3.5 8.29   MAL Mallard
including 168.7 169.6 0.9 25.4
WST-22-1006-W1 434.8 437.4 2.6 13.6   LX4 Lynx 4
including 434.8 436.0 1.2 29.0
WST-22-1010 387.9 390.0 2.1 37.9 LX4 Lynx 4
including 387.9 388.8 0.9 87.7
WST-22-1011 343.5 345.5 2.0 3.65 TLX Triple Lynx
including 343.8 344.1 0.3 13.8
WST-22-1014 254.7 257.7 3.0 3.89 LHW_3224 Lynx HW
  318.8 322.0 3.2 4.38 LXM Lynx
WST-22-1016 174.0 177.3 3.3 4.92 TLX Triple Lynx
including 176.6 177.3 0.7 15.3
  195.2 198.0 2.8 243 41.4 TLX Triple Lynx
including 195.7 196.0 0.3 1495 100

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below., MAL = Mallard, LXM = Lynx Main, LX4 = Lynx 4, LHW = Lynx Hanging wall, and TLX = Triple Lynx.

 Drill hole location

Hole No. Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-21-2601-W2 125 -61 1500 453425 5435656 412 3900
OSK-W-21-2605-W1 112 -55 1380 453551 5435669 408 4025
OSK-W-22-2587-W3 127 -59 1221 453350 5435673 413 3850
OSK-W-22-2605-W2 112 -55 1431 453551 5435669 408 4025
OSK-W-22-2605-W3 112 -55 1455 453551 5435669 408 4025
WST-21-0708 134 -40 670 453374 5435296 -26 3675
WST-21-0892 138 -25 116 453314 5435164 124 3550
WST-21-0926 149 -27 111 453314 5435164 124 3550
WST-21-0938 146 -22 106 453314 5435164 124 3550
WST-21-0939A 150 -24 129 453315 5435164 124 3550
WST-21-0940 148 -21 127 453315 5435165 125 3550
WST-21-0941 153 -23 129 453315 5435164 124 3550
WST-21-0942 148 -20 126 453315 5435164 124 3550
WST-21-0946 168 -51 403 453507 5435327 -7 3800
WST-21-0991 134 -29 391 453461 5435326 32 3775
WST-22-1003A 355 -57 213 452206 5434903 247 2475
WST-22-1006-W1 121 -45 628 453506 5435326 -90 3800
WST-22-1006-W2 121 -45 628 453506 5435326 -90 3800
WST-22-1010 136 -28 481 453445 5435276 -99 3725
WST-22-1011 134 -32 630 453344 5435312 -66 3650
WST-22-1012 141 -50 579 453322 5435236 54 3600
WST-22-1013 142 -44 420 453360 5435297 -149 3675
WST-22-1014 123 -37 540 453507 5435332 -47 3800
WST-22-1016 143 -65 448 453647 5435347 -189 3950

 

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.

 

Mallard

Mineralization is hosted in sheared mafic volcanics with felsic porphyritic intrusions and occurs as veins associated with sericite-pyrite ± silica ± chlorite alteration and contains pyrite ranging from trace to 30% and local visible gold.

 

 

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 January 10, 2022 is supported by the technical report entitled “Mineral Resource Estimate Update for the Windfall Project” dated February 10, 2022 (with an effective date  of October 21, 2021), and assuming a cut-off grade of 3.50 g/t Au, comprises 565,000 tonnes at 11.6 g/t Au (210,000 ounces) in the measured mineral resource category, 8,907,000 tonnes at 10.5 g/t Au (2,994,000 ounces) in the indicated mineral resource category and 13,035,000 tonnes at 8.6 g/t Au (3,585,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in the January 10, 2022, news release, certain of which are described in the January 10, 2022, news release, are further described in the full technical report for this updated mineral resource estimate 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 2,500 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