OSISKO WINDFALL INFILL AND EXPANSION DRILLING CONTINUES TO ADD HIGH-GRADE

75.4 g/t Au Over 3.2 Metres in Triple Lynx

103 g/t Au Over 2.3 Metres and 105 g/t Au Over 2.0 Metres in Lynx

(Toronto, July 07, 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 60 intercepts in 20 drill holes (5 from surface, 15 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 in a defined zone or corridor but do not yet correlate to a specific wireframe.

Osisko Chief Executive Officer John Burzynski commented: “Infill and expansion drilling from across the Windfall deposit continues to progress well. In particular, the focused infill drilling in all the Lynx zones consistently returns well distributed high-grade and expansion drilling is adding ounces. WST-21-0810 and OSK-W-21-2123-W5 both extended Triple Lynx wireframes, 25 metres and 40 meters at depth, respectively.”

Selected high-grade intercepts include: 75.4 g/t Au over 3.2 metres and 86.9 g/t Au over 2.4 metres  in OSK-W-21-2470-W4; 103 g/t Au over 2.3 metres in WST-21-0722; 105 g/t Au over 2.0 metres in WST-21-0716; 29.5 g/t Au over 6.0 metres in OSK-W-21-2067-W8; 87.1 g/t Au over 2.0 metres in OSK-W-21-2067-W7; 42.3 g/t Au over 3.0 metres in OSK-W-21-1882-W3; 60.6 g/t Au over 2.0 metres in WST-21-0721 and 30.7 g/t Au over 3.9 metres in WST-21-0682B. 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-21-1882-W3 829.3 832.3 3.0 42.3   UDD_4102 Underdog
including 831.3 832.3 1.0 85.2  
  936.0 938.0 2.0 4.12   UDD_4511 Underdog
including 936.0 936.5 0.5 16.3  
OSK-W-21-2067-W7 1136.0 1138.0 2.0 87.1 20.1 TLX_3172 Triple Lynx
including 1136.8 1137.2 0.4 435 100
OSK-W-21-2067-W8 1112.0 1118.0 6.0 29.5 20.1 TLX_3170 Triple Lynx
including 1115.4 1116.1 0.7 181 100
OSK-W-21-2275-W7 675.0 677.0 2.0 4.70   TLX_3196 Triple Lynx
including 675.4 676.0 0.6 14.6  
OSK-W-21-2470-W4 956.0 958.0 2.0 3.85   TLX_3163 Triple Lynx
  961.6 964.0 2.4 86.9 35.3 TLX_3163 Triple Lynx
including 962.0 962.8 0.8 255 100
  987.8 991.0 3.2 75.4 45.6 TLX_3164 Triple Lynx
including 987.8 988.5 0.7 236 100
OSK-W-21-2478-W5 860.0 862.1 2.1 16.7   TLX_3184 Triple Lynx
including 860.7 861.7 1.0 34.1  
OSK-W-21-2479-W4 651.3 653.3 2.0 41.5 40.3 UDD_4100 Underdog
including 653.0 653.3 0.3 108 100
OSK-W-21-2503-W1 1022.8 1024.8 2.0 9.75   TLX_3164 Triple Lynx
including 1024.2 1024.8 0.6 25.6  
OSK-W-21-2520 639.0 643.2 4.2 9.87   CA2_2206 Caribou
including 639.0 639.3 0.3 64.6  
and 642.5 643.2 0.7 26.3  
OSK-W-21-2522-W1 655.2 657.3 2.1 10.0   LXM_3304 Lynx
including 656.2 656.6 0.4 41.6  
  747.1 749.4 2.3 4.58   LXM_3345 Lynx
including 747.8 748.4 0.6 17.1  
OSK-W-21-2523 503.5 507.7 4.2 4.27   CA2_2247 Caribou
including 503.5 504.0 0.5 13.1  
  511.0 513.1 2.1 3.61   CA2_2241 Caribou
  522.7 529.0 6.3 8.53   CA2_2233 Caribou
including 528.4 529.0 0.6 39.7  
OSK-W-21-2532 452.0 454.0 2.0 24.7   Caribou_2232 Caribou
including 453.0 454.0 1.0 49.0  
OSK-W-21-2534 558.4 560.6 2.2 9.81   Caribou_2247 Caribou
WST-21-0682A 89.8 92.0 2.2 19.8   LXM_3339 Lynx
including 90.1 91.0 0.9 47.7  
WST-21-0682B 105.5 107.6 2.1 6.82   LXM_3311 Lynx
including 106.9 107.3 0.4 25.7  
  349.0 352.0 3.0 32.7 29.9 TLX_3166 Triple Lynx
including 349.0 349.3 0.3 128 100
  357.6 361.5 3.9 30.7   TLX_3166 Triple Lynx
including 358.0 358.6 0.6 68.0  
and 360.8 361.5 0.7 78.0  
  363.5 365.7 2.2 5.78   TLX_3166 Triple Lynx
  456.0 458.0 2.0 24.5   TLX_3130 Triple Lynx
including 456.0 456.6 0.6 74.6  
WST-21-0716 26.5 28.5 2.0 22.1   LXM_3303 Lynx
including 27.1 28.0 0.9 47.4  
  81.0 83.0 2.0 105 33.1 LXM_3304 Lynx
including 81.4 82.0 0.6 339 100
  87.0 89.0 2.0 17.7   LXM_3304 Lynx
including 87.0 87.7 0.7 50.4  
WST-21-0720 80.2 82.5 2.3 8.25   LXM_3336 Lynx
including 80.8 81.3 0.5 35.9  
  92.3 94.7 2.4 8.99   LXM_3304 Lynx
WST-21-0721 92.0 94.0 2.0 60.6 60.2 LXM_3304 Lynx
including 92.4 93.6 1.2 101 100
WST-21-0722 25.3 27.6 2.3 103 25.2 LXM_3303 Lynx
including 26.5 27.0 0.5 459 100
WST-21-0759 325.1 327.2 2.1 3.96   TLX_3131 Triple Lynx
WST-21-0778 313.4 315.7 2.3 5.23   TLX_3131 Triple Lynx
including 314.4 315.0 0.6 18.0  
  511.0 513.0 2.0 28.3   LX4_3429 Lynx 4
including 512.0 513.0 1.0 51.5  
WST-21-0789B 325.6 327.9 2.3 8.20   TLX_3166 Triple Lynx
including 325.9 326.8 0.9 17.0  
WST-21-0801 306.5 308.6 2.1 11.5   LSW_3556 Lynx Southwest
including 307.0 307.7 0.7 33.7  
WST-21-0810 344.0 346.0 2.0 4.77   TLX_3131 Triple Lynx
  373.0 376.0 3.0 5.08   TLX_3167 Triple Lynx
  531.0 533.0 2.0 33.8 25.2 LX4_3450 Lynx 4
including 532.1 532.6 0.5 135 100
  736.8 738.9 2.1 22.2   LX4_3412 Lynx 4
including 737.6 737.9 0.3 78.9  
WST-21-0815 81.0 83.0 2.0 4.09   Z27_1102 Zone 27
WST-21-0819A 79.0 81.0 2.0 3.89   Z27_1115 Zone 27
including 80.1 81.0 0.9 8.45  
WST-21-0820 92.5 95.0 2.5 3.56   Z27_1102 Zone 27
WST-21-0827 247.7 250.0 2.3 13.4   TLX_3161 Triple Lynx

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. Z27 = Zone 27, CA2 = Caribou 2, LSW = Lynx Southwest, LXM = Lynx Main, LX4 = Lynx 4, TLX = Triple Lynx, and UDD = Underdog.

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-21-2123-W5 1154.6 1159.0 4.4 16.6   Triple Lynx Lynx
including 1154.6 1155.0 0.4 42.9  
and 1156.0 1156.4 0.4 61.4  
and 1157.6 1158.0 0.4 41.9  
  1203.0 1205.0 2.0 5.59   Triple Lynx Lynx
including 1203.8 1204.1 0.3 13.3  
  1209.0 1211.0 2.0 4.32   Triple Lynx Lynx
OSK-W-21-2470-W3 956.8 958.8 2.0 45.7 30.6 Triple Lynx Lynx
including 957.3 957.9 0.6 151 100
  989.8 991.8 2.0 16.2   Triple Lynx Lynx
including 991.2 991.5 0.3 80.1  
OSK-W-21-2479-W4 426.0 428.0 2.0 19.2   Zone 27 Main Zone
including 427.3 428.0 0.7 49.9  
OSK-W-21-2480-W3 731.5 733.5 2.0 26.4   Lynx Lynx
including 732.5 733.5 1.0 51.8  
OSK-W-21-2523 409.5 412.0 2.5 7.42   Caribou Main Zone
including 409.5 410.3 0.8 16.2  
OSK-W-21-2540 824.5 826.5 2.0 4.94   Lynx Main Lynx
including 825.9 826.5 0.6 15.8  
WST-21-0682B 375.0 377.0 2.0 4.08   Lynx SW Lynx
  384.0 386.1 2.1 5.90   Lynx SW Lynx
including 385.6 386.1 0.5 24.2  
WST-21-0759 29.7 32.0 2.3 6.83   Lynx Main Lynx
WST-21-0778 323.0 325.0 2.0 10.7   Triple Lynx Lynx
including 323.3 323.6 0.3 69.0  
WST-21-0789B 371.0 373.0 2.0 4.42   Triple Lynx Lynx
including 372.6 373.0 0.4 19.3  
WST-21-0810 450.2 453.0 2.8 25.2   Triple Lynx Lynx
including 452.5 453.0 0.5 96.7  

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

 

Drill hole location

Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-21-1882-W3 328 -58 1004 452469 5434405 400 2450
OSK-W-21-2067-W7 123 -53 1166 453241 5435697 416 3750
OSK-W-21-2067-W8 123 -53 1191 453241 5435697 416 3750
OSK-W-21-2123-W5 126 -57 1332 453235 5435774 409 3800
OSK-W-21-2275-W7 127 -49 1182 452888 5435583 409 3400
OSK-W-21-2470-W3 132 -59 1209 453304 5435639 415 3775
OSK-W-21-2470-W4 132 -59 1155 453304 5435639 415 3775
OSK-W-21-2478-W5 128 -54 1166 452997 5435607 425 3500
OSK-W-21-2479-W4 344 -55 761 452315 5434419 399 2325
OSK-W-21-2480-W3 121 -55 810 453412 5435633 412 3875
OSK-W-21-2503-W1 126 -58 1161 453333 5435641 413 3800
OSK-W-21-2520 337 -56 1140 452596 5434392 401 2550
OSK-W-21-2522-W1 128 -54 1116 453451 5435594 411 3900
OSK-W-21-2523 340 -58 1107 452480 5434428 402 2475
OSK-W-21-2532 341 -60 1107 452480 5434428 401 2475
OSK-W-21-2534 343 -59 1203 452549 5434363 401 2500
OSK-W-21-2540 117 -60 1025 453465 5435640 410 3925
WST-21-0682A 133 -66 139 453106 5435066 231 3325
WST-21-0682B 129 -64 472 453106 5435066 231 3325
WST-21-0716 160 -3 97 453359 5435194 83 3625
WST-21-0720 162 2 103 453359 5435194 84 3625
WST-21-0721 166 -1 103 453359 5435194 83 3625
WST-21-0722 166 1 106 453359 5435194 84 3625
WST-21-0759 141 -43 680 453321 5435235 54 3600
WST-21-0778 145 -31 534 453374 5435296 -26 3675
WST-21-0789B 125 -55 381 453106 5435066 231 3325
WST-21-0801 139 -54 418 452954 5435003 253 3175
WST-21-0810 138 -47 765 453257 5435209 96 3525
WST-21-0815 159 0 99 451960 5434734 250 2175
WST-21-0819A 173 -2 100 451957 5434735 250 2175
WST-21-0820 179 18 115 451957 5434735 250 2175
WST-21-0827 145 -66 313 453507 5435327 -7 3800

 

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.

 

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.

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.

 

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