OSISKO DRILLING AT WINDFALL RETURNS HIGH GRADE AT LYNX

296 g/t Au Over 2.0 Metres in Lynx

(Toronto, April 27, 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 56 intercepts in 23 drill holes (7 from surface, 16 from underground) and 12 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 located in a defined zone or corridor but do not yet correlate to a specific wireframe.

Osisko Chief Executive Officer John Burzynski commented: “We are encouraged by the expansion drilling in the Lynx and Triple Lynx areas. Today’s 37 expansion intercepts in these corridors are a good indication of the continuing potential in these zones.”

Selected high-grade intercepts include: 296 g/t Au over 2.0 metres in OSK-W-21-2436-W3; 177 g/t Au over 2.1 metres in OSK-W-21-2436-W2, 54.2 g/t Au over 4.5 metres in WST-21-0675, 63.7 g/t Au over 2.0 metres in WST-21-0744, and 48.2 g/t Au over 2.0 metres in OSK-W-20-2426. 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-21-2436-W2 714.4 716.5 2.1 177 35.1 LX4_3414 Lynx 4
including 715.0 715.6 0.6 595 100
OSK-W-21-2436-W3 760.0 762.0 2.0 296 55.6 LX4_3414 Lynx 4
including 760.4 761.1 0.7 757 100
  867.0 869.0 2.0 14.6   LX4_3430 Lynx 4
including 868.0 869.0 1.0 29.1  
OSK-W-21-2445-W3 601.6 605.1 3.5 3.68   TLX_3171 Triple Lynx
OSK-W-21-2480-W1 748.0 750.2 2.2 24.4   LXM_3304 Lynx
including 748.5 749.2 0.7 76.4  
OSK-W-21-2482 636.0 638.6 2.6 3.98   TLX_3171 Triple Lynx
  664.9 667.0 2.1 4.11   TLX_3184 Triple Lynx
including 665.7 666.0 0.3 26.7  
WST-20-0617 351.7 358.0 6.3 7.44   TLX_3167 Triple Lynx
including 352.1 352.4 0.3 83.1  
WST-21-0683 342.8 344.8 2.0 3.83   TLX_3166 Triple Lynx
  371.0 374.8 3.8 8.72   TLX_3165 Triple Lynx
including 373.9 374.8 0.9 27.1  
WST-21-0691 250.0 254.0 4.0 6.29   TLX_3164 Triple Lynx
  257.2 259.6 2.4 13.8   TLX_3164 Triple Lynx
WST-21-0697 379.4 381.7 2.3 4.55   TLX_3166 Triple Lynx
  426.0 428.0 2.0 11.4   TLX_3165 Triple Lynx
including 426.5 427.4 0.9 23.5  
WST-21-0706 269.5 273.3 3.8 7.68   LXSW_3556 Lynx
including 269.8 270.3 0.5 23.7  
WST-21-0748 200.0 202.4 2.4 37.4   LXM_3304 Lynx
including 201.6 202.4 0.8 93.5  
WST-21-0786 124.3 127.2 2.9 7.21   LXM_3334 Lynx

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, TLX = Triple Lynx and LXSW = Lynx Southwest.

 

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-20-2397-W1 818.9 821.0 2.1 4.32   Lynx Lynx
OSK-W-20-2426 912.0 914.0 2.0 48.2 25.2 Triple Lynx Triple Lynx
including 912.7 913.2 0.5 192 100
OSK-W-21-2369-W3 1215.9 1218.0 2.1 5.17   Lynx 4 Lynx
  1223.7 1226.1 2.4 15.5   Lynx 4 Lynx
OSK-W-21-2394-W4 908.0 910.0 2.0 3.85   Triple Lynx Triple Lynx
OSK-W-21-2394-W6 580.0 582.0 2.0 3.58   Triple Lynx Triple Lynx
including 580.0 580.9 0.9 7.90  
OSK-W-21-2416-W1 841.3 844.0 2.7 4.69   Triple Lynx Triple Lynx
including 841.3 841.9 0.6 10.8  
OSK-W-21-2416-W2 1125.0 1127.0 2.0 9.52   Triple Lynx Triple Lynx
including 1125.8 1126.6 0.8 21.0  
OSK-W-21-2445 932.0 934.0 2.0 14.9   Triple Lynx Triple Lynx
including 932.0 933.0 1.0 26.2  
OSK-W-21-2445-W3 612.2 614.2 2.0 9.96   Triple Lynx Triple Lynx
including 612.6 613.1 0.5 31.0  
  694.8 697.0 2.2 5.72   Triple Lynx Triple Lynx
OSK-W-21-2445-W4 602.0 604.0 2.0 5.09   Triple Lynx Triple Lynx
including 602.5 602.9 0.4 23.8  
OSK-W-21-2459 1088.3 1090.4 2.1 5.25   Triple Lynx Triple Lynx
including 1088.3 1088.6 0.3 36.4  
OSK-W-21-2465 903.0 905.0 2.0 19.9   Lynx 4 Lynx
including 903.9 904.7 0.8 49.0  
OSK-W-21-2470-W1 1115.0 1117.0 2.0 5.67   Triple Lynx Triple Lynx
  1160.0 1162.0 2.0 17.2 16.5 Triple Lynx Triple Lynx
including 1160.8 1161.1 0.3 105 100
OSK-W-21-2473 992.4 994.4 2.0 6.94   Triple Lynx Triple Lynx
including 993.7 994.4 0.7 19.5  
  997.0 999.0 2.0 5.30   Triple Lynx Triple Lynx
including 998.4 999.0 0.6 17.2  
OSK-W-21-2480-W1 697.3 699.6 2.3 6.24   Lynx Lynx
including 699.2 699.6 0.4 16.2  
OSK-W-21-2482 642.5 644.6 2.1 3.64   Triple Lynx Triple Lynx
  825.7 827.7 2.0 25.8   Triple Lynx Triple Lynx
OSK-W-21-2493 1064.0 1066.1 2.1 17.3   Lynx 4 Lynx
including 1064.8 1065.4 0.6 49.5  
WST-21-0657 402.0 404.2 2.2 24.6   Triple Lynx Triple Lynx
including 402.0 402.5 0.5 94.0  
WST-21-0665 394.0 397.0 3.0 10.5   TLX_3165 Triple Lynx
including 396.4 397.0 0.6 39.7  
WST-21-0675 271.5 276.0 4.5 54.2 25.8 Lynx HW Lynx
including 274.0 275.0 1.0 228 100
WST-21-0676 123.0 125.3 2.3 4.73   Lynx Lynx
including 124.5 125.3 0.8 10.2  
  217.0 219.0 2.0 5.72   Lynx Lynx
WST-21-0678 495.8 497.9 2.1 11.8   Triple Lynx Triple Lynx
including 496.6 497.6 1.0 24.2  
WST-21-0683 355.0 358.0 3.0 7.62   Triple Lynx Triple Lynx
including 355.0 356.0 1.0 17.2  
  544.0 546.0 2.0 5.55   Lynx 4 Lynx
WST-21-0690 242.5 244.6 2.1 13.0   Triple Lynx Triple Lynx
including 243.3 243.6 0.3 49.2  
  249.6 251.6 2.0 5.13   Triple Lynx Triple Lynx
  252.6 254.7 2.1 4.67   Triple Lynx Triple Lynx
including 254.3 254.7 0.4 10.2  
WST-21-0703 309.5 311.7 2.2 5.38   Lynx SW Lynx SW
WST-21-0706 250.7 253.0 2.3 5.17   Lynx SW Lynx SW
WST-21-0744 115.2 117.2 2.0 63.7 20.1 Lynx Lynx
including 115.8 116.2 0.4 318 100
  119.1 121.4 2.3 11.2   Lynx Lynx
WST-21-0749 128.3 130.4 2.1 9.29   LXM_3338 Lynx
including 129.0 129.7 0.7 22.2  
  144.9 146.9 2.0 37.1   Lynx Lynx

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. LXM = Lynx Main, TLX = Triple Lynx and SW = Southwest.

 

Drill hole location

Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-20-2397-W1 131 -58 1200 453451 5435594 412 3900
OSK-W-20-2426 134 -56 1035 453008 5435388 413 3400
OSK-W-21-2369-W3 130 -56 1415 453424 5435566 410 3850
OSK-W-21-2394-W4 138 -52 920 452923 5435467 414 3375
OSK-W-21-2394-W6 138 -52 978 452923 5435467 414 3375
OSK-W-21-2416-W1 123 -54 1083 453169 5435624 412 3650
OSK-W-21-2416-W2 123 -54 1266 453169 5435624 412 3650
OSK-W-21-2436-W2 130 -57 789 453709 5435618 400 4125
OSK-W-21-2436-W3 130 -57 879 453709 5435618 400 4125
OSK-W-21-2445 141 -50 945 452906 5435434 415 3325
OSK-W-21-2445-W3 141 -50 753 452906 5435434 415 3325
OSK-W-21-2445-W4 141 -50 944 452906 5435434 415 3325
OSK-W-21-2459 132 -52 1227 452997 5435607 425 3500
OSK-W-21-2465 123 -61 1253 453397 5435557 413 3825
OSK-W-21-2470-W1 132 -59 1227 453304 5435639 415 3775
OSK-W-21-2473 123 -56 1272 453420 5435610 413 3875
OSK-W-21-2480-W1 121 -55 888 453412 5435633 412 3875
OSK-W-21-2482 131 -57 939 453008 5435388 413 3400
OSK-W-21-2493 134 -54 1080 453008 5435388 412 3400
WST-20-0617 134 -41 366 453257 5435210 95 3525
WST-21-0657 141 -56 448 453357 5435272 16 3650
WST-21-0665 141 -52 552 453229 5435127 134 3475
WST-21-0675 133 -40 336 453508 5435327 -7 3800
WST-21-0676 129 -32 318 453508 5435327 -7 3800
WST-21-0678 153 -50 574 453321 5435235 55 3600
WST-21-0683 146 -40 636 453257 5435210 95 3525
WST-21-0690 150 -63 307 453356 5435272 16 3650
WST-21-0691 152 -58 385 453356 5435272 16 3650
WST-21-0697 136 -45 542 453257 5435209 96 3525
WST-21-0703 146 -60 489 453104 5435065 231 3325
WST-21-0706 165 -54 417 453104 5435065 231 3325
WST-21-0744 136 -27 186 453508 5435327 -6 3800
WST-21-0748 125 -54 267 453508 5435327 -7 3800
WST-21-0749 136 -30 196 453357 5435272 16 3650
WST-21-0786 150 -39 140 453322 5435235 55 3600

 

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 3.0 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 defined by Osisko, as disclosed in the news release dated February 17, 2021 and supported by the technical report entitled “Mineral Resource Estimate Update for the Windfall Project, Eeyou Istchee James Bay, Québec, Canada” dated March 8, 2021 (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