Category: Silver / Gold

Osisko Drilling Returns High Grade at Lynx

180 g/t Au Over 2.2 Metres
46.8 g/t Au Over 3.3 Metres
 
TORONTO, May 11, 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 28 intercepts in 18 drill holes (5 from surface, 13 from underground) and 3 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: “Today’s infill results continue to demonstrate the strong continuity inside defined MRE blocks as well as our ability to add resources in the immediate surrounding areas.”

Selected high-grade intercepts include: 180 g/t Au over2.2metres in OSK-W-21-2495; 46.8 g/tAu over 3.3 metres in OSK-W-21-2470, 32.2 g/t Auover 2.4 metres in OSK-W-21-2480, 27.2 g/t Auover 2.0 metres in WST-20-0585 and 21.9 g/t Au over 2.3 metres in WST-20-0639B. Maps showing hole locations and full analytical results are available at www.osiskomining.com

Infill Drilling

Hole Number From (m) To (m) Interval (m) Au (g/t) uncut Au (g/t) cut to 100 g/t Zone Corridor
OSK-W-20-2313-W9 826.3 829.0 2.7 6.53   TLX_3184 Triple Lynx
including 827.2 827.9 0.7 24.0  
  832.7 835.0 2.3 7.10   TLX_3184 Triple Lynx
including 833.5 834.4 0.9 17.4  
OSK-W-20-2394-W3 659.0 663.0 4.0 4.16   TLX_3171 Triple Lynx
OSK-W-21-2470 993.0 996.3 3.3 46.8 34.3 TLX_3164 Triple Lynx
including 993.4 993.8 0.4 203 100
OSK-W-21-2482 625.3 627.6 2.3 10.4   TLX_3171 Triple Lynx
including 626.4 627.0 0.6 23.2  
OSK-W-21-2495 1023.0 1025.0 2.0 4.80   LX4_3430 Lynx
including 1023.0 1023.3 0.3 18.0  
  1027.0 1029.2 2.2 180 30.7 LX4_3430 Lynx
including 1027.5 1028.1 0.6 646 100
WST-20-0585 157.7 159.7 2.0 27.2   LXM_3359 Lynx
including 158.2 159.0 0.8 63.4  
WST-20-0639B 269.0 271.3 2.3 21.9   LSX_3510 Lynx SW
including 269.5 270.4 0.9 41.7  
  298.0 300.0 2.0 3.62   LSX_3556 Lynx
including 298.4 298.8 0.4 11.1  
WST-21-0665 328.4 331.0 2.6 4.59   TLX_3166 Triple Lynx
including 330.4 331.0 0.6 11.4  
WST-21-0677 490.4 492.4 2.0 11.8   LX4_3450 Lynx
including 491.8 492.4 0.6 39.1  
WST-21-0696 276.6 279.2 2.6 3.66   TLX_3166 Triple Lynx
including 277.4 278.2 0.8 10.8  
WST-21-0709 27.0 29.3 2.3 6.72   LXM_3303 Lynx
including 27.6 28.7 1.1 13.8  
WST-21-0710 28.0 30.0 2.0 5.14   LXM_3303 Lynx
  79.0 81.0 2.0 18.5   LXM_3304 Lynx
including 79.6 80.3 0.7 52.5  
WST-21-0729 398.0 403.0 5.0 3.69   TLX_3165 Triple Lynx
including 402.6 403.0 0.4 14.7  
WST-21-0735 338.0 340.1 2.1 5.06   LSX_3501 Lynx SW
including 338.8 339.1 0.3 34.5  

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 LSX = Lynx Southwest (SW).

Expansion Drilling

Hole Number From (m) To (m) Interval (m) Au (g/t) uncut Au (g/t) cut to 100 g/t Zone Corridor
OSK-W-21-2480 997.8 1000.2 2.4 32.2 25.1 Lynx 4 Lynx
including 998.9 999.5 0.6 129 100
OSK-W-21-2487 691.2 693.3 2.1 5.28   Lynx 4 Lynx
including 691.7 692.5 0.8 12.2  
OSK-W-21-2487-W2 655.0 657.0 2.0 5.14   Lynx 4 Lynx
OSK-W-21-2495 986.0 988.0 2.0 4.46   Lynx 4 Lynx
WST-21-0640A 308.7 311.0 2.3 4.90   Lynx SW Lynx SW
  342.0 344.0 2.0 4.85   Lynx SW Lynx SW
including 342.5 343.1 0.6 16.0  
WST-21-0680 51.5 54.0 2.5 4.11   Lynx Lynx
WST-21-0692 532.3 534.9 2.6 12.7   Triple Lynx Triple Lynx
including 532.3 532.6 0.3 71.8  
WST-21-0729 421.3 425.3 4.0 5.72   Lynx 4 Lynx
including 421.3 421.8 0.5 26.9  
WST-21-0757 630.9 633.0 2.1 6.99   Lynx 4 Lynx
including 630.9 631.7 0.8 18.3  

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See "Quality Control and Reporting Protocols" below. SW = Lynx Southwest (SW).

Drill hole location

Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-20-2313-W9 134 -52 1218 452965 5435583 420 3450
OSK-W-20-2394-W3 138 -52 1020 452923 5435467 414 3375
OSK-W-21-2470 132 -59 1230 453304 5435639 415 3775
OSK-W-21-2480 121 -55 1230 453412 5435633 412 3875
OSK-W-21-2482 131 -57 939 453009 5435387 413 3400
OSK-W-21-2487 359 -73 897 454135 5435058 397 4225
OSK-W-21-2487-W2 359 -73 777 454135 5435058 397 4225
OSK-W-21-2495 123 -54 1257 453426 5435565 410 3850
WST-20-0585 161 -25 189 453418 5435305 69 3725
WST-20-0639B 147 -54 351 453105 5435065 231 3325
WST-21-0640A 165 -51 456 453104 5435064 231 3325
WST-21-0665 141 -52 552 453229 5435127 134 3475
WST-21-0677 144 -42 652 453257 5435209 96 3525
WST-21-0680 161 -47 559 453322 5435235 55 3600
WST-21-0692 157 -54 541 453356 5435272 16 3650
WST-21-0696 137 -49 492 453229 5435127 134 3475
WST-21-0709 155 -7 94 453360 5435194 83 3625
WST-21-0710 154 -9 94 453360 5435195 83 3625
WST-21-0729 132 -49 510 453229 5435127 135 3475
WST-21-0735 132 -58 475 452956 5435003 253 3175
WST-21-0757 145 -50 706 453228 5435126 135 3475

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
Truewidthdeterminationisestimatedat55-80%ofthereportedcorelengthintervalforthezone.Assaysareuncutexceptwhere 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 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 occursinthreeprincipalzones:Lynx,Main Zone,andUnderdog.Mineralization is generallycomprised ofsub-vertical zonesfollowingintrusive porphyrycontactsplungingtothenortheast.The resources are defined fromsurfacetoadepthof1,600metres 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 remainsopen alongstrikeandatdepth.Mineralizationhasbeenidentifiedatsurfaceinsomeareasandasdeepas2,625metres in others with significant potential to extend mineralization down-plunge and atdepth.

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 ChibougamauinQuébecandholdsa100%undividedinterestinalargeareaofclaimsinthesurroundingUrbanBarryarea and nearby Quévillon area (over 2,700 squarekilometres).

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