OSISKO DRILLING RETURNS 2181 g/t Au OVER 2.5 METRES IN LYNX

293 g/t Au Over 4.0 Metres in Zone 27

(Toronto, August 3, 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 73 intercepts in 22 drill holes (6 from surface, 16 from underground) and 16 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 once again delivers outstanding results across the deposit. Six of our top results this week are greater than 200 g/t Au over 2.0 metres and three of these intervals have sub-intervals between two to six kilograms of gold per ton. These six holes are infill holes, once again confirming the high-grade nature of the deposit. Expansion drilling is also delivering; OSK-W-21-1949-W6 is 80 metres from the nearest resource block in the Lynx 4 corridor”.

Selected high-grade intercepts include: 2181 g/t Au over 2.5 metres and 403 g/t Au over 2.2 metres  in OSK-W-21-2287-W1; 293 g/t Au over 4.4 metres in WST-21-0814; 350 g/t Au over 2.1 metres in OSK-W-21-2470-W6; 209 g/t Au over 2.9 metres in OSK-W-21-1432-W4; 218 g/t Au over 2.0 metres in OSK-W-21-2503-W2; 91.0 g/t Au over 3.8 metres in OSK-W-21-1432-W3; 82.1 g/t Au over 3.2 metres in WST-21-0811A; 89.0 g/t Au over 2.6 metres in OSK-W-21-2509; 94.2 g/t Au over 2.1 metres in OSK-W-21-2492-W5. 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-W3 1033.4 1037.2 3.8 91.0 41.3 LX4_3446 Lynx 4
including 1033.4 1034.3 0.9 304 100
OSK-W-21-1432-W4 866.0 868.9 2.9 209 65.9 LX4_3424 Lynx 4
including 867.0 867.9 0.9 480 100
OSK-W-21-1827-W3 946.0 948.4 2.4 5.84   UDD_4515 Underdog
including 947.4 947.9 0.5 27.2
OSK-W-21-1949-W5 643.2 648.0 4.8 8.18 LXM_3304 Lynx
including 645.3 645.9 0.6 25.5
1095.0 1097.2 2.2 7.28   LX4_3430 Lynx 4
OSK-W-21-2067-W9 1136.0 1138.3 2.3 36.4 23.7 TLX_3172 Triple Lynx
including 1137.5 1137.8 0.3 198 100
OSK-W-21-2287-W1 1209.9 1212.4 2.5 2181 57.4 LX4_3449 Lynx 4
including 1210.4 1211.3 0.9 5950 100
1215.0 1217.2 2.2 403 99.3 LX4_3449 Lynx 4
including 1216.1 1217.2 1.1 708 100
OSK-W-21-2287-W2 1149.7 1152.1 2.4 6.15   LX4_3455 Lynx 4
including 1151.3 1152.1 0.8 16.4
  1245.0 1248.4 3.4 4.54   LX4_3449 Lynx 4
  1262.4 1264.7 2.3 40.9 30.4 LX4_3445 Lynx 4
including 1264.1 1264.7 0.6 140 100
1278.6 1280.7 2.1 57.0 34.1 LX4_3445 Lynx 4
including 1279.0 1279.7 0.7 169 100
OSK-W-21-2470-W6 812.5 814.7 2.2 4.27   TLX_3173 Triple Lynx
958.0 960.1 2.1 350 36.0 TLX_3163 Triple Lynx
including 959.8 960.1 0.3 2300 100
  967.0 969.5 2.5 10.1   TLX_3163 Triple Lynx
  1037.0 1039.0 2.0 5.73   TLX_3162 Triple Lynx
1044.0 1046.2 2.2 10.3   TLX_3170 Triple Lynx
including 1045.6 1045.9 0.3 50.1
1081.0 1083.0 2.0 5.45 TLX_3172 Triple Lynx
including 1082.3 1082.6 0.3 23.1
OSK-W-21-2492-W5 788.7 790.8 2.1 94.2 55.2 LX4_3424 Lynx 4
including 789.5 789.9 0.4 239 100
OSK-W-21-2503-W2 1121.0 1123.0 2.0 218 37.3 TLX_3172 Triple Lynx
including 1121.7 1122.4 0.7 617 100
OSK-W-21-2528-W1 625.2 627.3 2.1 4.35   UDD_4914 Underdog
OSK-W-21-2531 1086.5 1092.0 5.5 3.57   UDD_4501 Underdog
OSK-W-21-2532 764.0 767.7 3.7 7.35   UDD_4116 Underdog
including 767.0 767.7 0.7 19.9
  997.0 999.0 2.0 5.04   UDD_4501 Underdog
  1023.0 1027.0 4.0 9.34   UDD_4502 Underdog
including 1024.1 1024.5 0.4 48.6
1032.0 1034.0 2.0 4.05   UDD_4513 Underdog
including 1032.9 1033.3 0.4 17.0
OSK-W-21-2534 984.0 986.1 2.1 7.81   UDD_4106 Underdog
including 985.2 985.5 0.3 49.8
1018.4 1020.4 2.0 16.1   UDD_4515 Underdog
including 1019.8 1020.1 0.3 75.7
OSK-W-21-2537 583.9 585.9 2.0 3.96   TLX_3178 Triple Lynx
OSK-W-21-2541 196.0 198.0 2.0 11.5   F51_6010 F-51
including 196.9 197.5 0.6 37.9
210.0 212.5 2.5 7.42   F51_6008 F-51
WST-21-0679 314.7 317.0 2.3 4.79   TLX_3131 Triple Lynx
WST-21-0726 235.7 237.8 2.1 32.9   TLX_3161 Triple Lynx
WST-21-0763A 503.0 505.0 2.0 5.08   LX4_3434 Lynx 4
including 507.0 509.0 2.0 3.73 LX4_3434 Lynx 4
WST-21-0794 266.3 268.3 2.0 22.7   LHW_3201 Lynx HW
including 267.2 267.8 0.6 68.7
WST-21-0797A 486.0 489.9 3.9 4.92   LX4_3450 Lynx 4
694.0 696.4 2.4 24.1   LX4 Lynx 4
including 694.6 695.0 0.4 96.8
  716.9 720.6 3.7 6.16   LX4_3415 Lynx 4
  724.0 726.0 2.0 39.5 32.1 LX4_3415 Lynx 4
including 725.7 726.0 0.3 149 100
WST-21-0811A 209.0 211.0 2.0 73.4 55.0 TLX_3161 Triple Lynx
including 210.0 210.5 0.5 158 100
310.0 313.2 3.2 82.1 34.2 TLX_3182 Triple Lynx
including 312.5 313.2 0.7 304 100
WST-21-0814 83.1 87.5 4.4 293 17.1 Z27_1102 Zone 27
including 83.1 83.5 0.4 3140 100
WST-21-0814A 67.3 69.7 2.4 27.2 22.4 Z27_1115 Zone 27
including 68.1 68.6 0.5 123 100
75.1 77.5 2.4 8.13   Z27_1102 Zone 27
including 76.3 76.6 0.3 46.4
WST-21-0817 74.0 76.0 2.0 4.64   Z27_1115 Zone 27
WST-21-0823 451.7 454.0 2.3 4.57   LX4_3430 Lynx 4
WST-21-0829 556.0 558.0 2.0 28.0   LX4_3450 Lynx 4
including 556.4 557.0 0.6 92.5
WST-21-0838 267.0 269.0 2.0 13.0   LSW_3506 Lynx SW
including 267.5 268.0 0.5 50.8
WST-21-0841 349.9 352.0 2.1 19.1   TLX_3166 Triple Lynx
including 350.5 351.5 1.0 39.6

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. Z27 = Zone 27, LXM = Lynx Main, LX4 = Lynx 4, LHW = Lynx Hanging Wall, 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-21-777-W2 627.6 629.6 2.0 9.53   Caribou Caribou
including 628.0 628.8 0.8 21.4    
OSK-W-21-1432-W4 907.8 910.0 2.2 16.4   LX4 Lynx 4
including 908.6 909.0 0.4 59.1
915.1 917.8 2.7 23.0 LX4 Lynx 4
including 916.2 917.0 0.8 60.9
OSK-W-21-1827-W4 548.0 550.1 2.1 7.94 Caribou Caribou
including 549.3 550.1 0.8 20.6
OSK-W-21-1949-W6 1175.0 1177.0 2.0 13.2 LX4 Lynx 4
including 1175.5 1176.0 0.5 30.1
OSK-W-21-2470-W6 927.0 929.2 2.2 4.18 TLX Triple Lynx
OSK-W-21-2478-W6 857.7 860.1 2.4 17.0 TLX_3171 Triple Lynx
including 859.4 860.1 0.7 54.8
OSK-W-21-2479-W5 754.5 757.4 2.9 35.7 23.0 Underdog Underdog
including 754.5 755.1 0.6 162 100
OSK-W-21-2503-W2 1142.5 1144.6 2.1 85.7 15.4 TLX Triple Lynx
including 1144.0 1144.3 0.3 592 100
OSK-W-21-2509 619.1 621.7 2.6 89.0 44.3 Triple Lynx Triple Lynx
including 620.3 621.0 0.7 266 100
OSK-W-21-2531 1035.0 1037.0 2.0 4.11   Underdog Underdog
including 1035.7 1036.1 0.4 17.2
1173.0 1176.6 3.6 5.85   UDD Underdog
including 1173.0 1174.0 1.0 15.9
OSK-W-21-2532 935.0 937.5 2.5 8.95   Underdog Underdog
including 936.5 936.9 0.4 41.6
1012.8 1015.0 2.2 25.3   UDD Underdog
including 1012.8 1013.3 0.5 97.6
OSK-W-21-2534 887.4 889.6 2.2 3.90   Underdog Underdog
WST-21-0726 337.3 339.4 2.1 24.4 17.6 TLX Triple Lynx
including 338.3 338.6 0.3 148 100
348.7 351.0 2.3 17.7   TLX_3131 Triple Lynx
including 349.1 349.9 0.8 49.9
WST-21-0776 229.6 231.6 2.0 10.0   Triple Lynx Triple Lynx
including 230.9 231.6 0.7 28.2
WST-21-0811A 471.8 474.5 2.7 3.60   LX4 Lynx 4
WST-21-0823 445.0 447.0 2.0 5.10   LX4 Lynx 4
WST-21-0826 347.9 350.0 2.1 13.8   TLX_3166 Triple Lynx
including 348.4 348.7 0.3 57.3
WST-21-0842 323.3 325.7 2.4 14.7 12.8 TLX Triple Lynx
including 323.3 323.6 0.3 116 100
333.8 337.3 3.5 5.28   TLX Triple Lynx
including 335.4 336.0 0.6 12.8
344.7 347.0 2.3 5.75   Triple Lynx Triple Lynx
including 346.2 347.0 0.8 15.4

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

 

Drill hole location

Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-21-777-W2 330 -59 1170 452678 5434500 403 2675
OSK-W-21-1432-W3 132 -55 1094 453811 5435779 400 4300
OSK-W-21-1432-W4 132 -55 1053 453811 5435779 400 4300
OSK-W-21-1827-W3 331 -58 1251 452506 5434390 403 2475
OSK-W-21-1827-W4 331 -58 1046 452506 5434390 403 2475
OSK-W-21-1949-W5 105 -57 1301 453440 5435479 401 3825
OSK-W-21-1949-W6 105 -57 1227 453440 5435479 401 3825
OSK-W-21-2067-W9 123 -53 1164 453241 5435697 416 3750
OSK-W-21-2287-W1 116 -53 1374 453607 5435714 404 4075
OSK-W-21-2287-W2 116 -53 1392 453607 5435714 404 4075
OSK-W-21-2470-W6 132 -59 1119 453304 5435639 415 3775
OSK-W-21-2478-W6 128 -54 948 452997 5435607 425 3500
OSK-W-21-2479-W5 344 -55 978 452315 5434419 399 2325
OSK-W-21-2492-W5 122 -53 888 453687 5435676 401 4125
OSK-W-21-2503-W2 126 -58 1199 453333 5435641 413 3800
OSK-W-21-2509 132 -56 663 452825 5435340 414 3225
OSK-W-21-2528-W1 333 -54 720 452469 5434682 403 2600
OSK-W-21-2531 344 -62 1188 452566 5434415 403 2550
OSK-W-21-2532 341 -60 1107 452480 5434428 401 2475
OSK-W-21-2534 343 -59 1203 452549 5434363 401 2500
OSK-W-21-2537 114 -54 1243 452981 5435549 420 3450
OSK-W-21-2541 149 -47 285 453541 5436007 405 4175
WST-21-0679 145 -46 441 453257 5435209 96 3525
WST-21-0726 149 -64 454 453507 5435327 -7 3800
WST-21-0763A 120 -39 567 453507 5435332 -47 3800
WST-21-0776 160 -44 376 453257 5435209 96 3525
WST-21-0794 121 -11 315 453463 5435327 33 3775
WST-21-0797A 138 -46 751 453321 5435235 54 3600
WST-21-0811A 125 -44 708 453375 5435296 -26 3675
WST-21-0814 154 -6 96 451960 5434734 249 2175
WST-21-0814A 154 5 97 451960 5434734 250 2175
WST-21-0817 169 -10 111 451958 5434734 249 2175
WST-21-0823 120 -35 545 453507 5435332 -47 3800
WST-21-0826 129 -59 403 453106 5435066 231 3325
WST-21-0829 131 -49 576 453258 5435209 96 3525
WST-21-0838 131 -56 366 453106 5435066 231 3325
WST-21-0841 125 -65 438 453106 5435066 231 3325
WST-21-0842 156 -69 445 453506 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.

F-Zones

Mineralization is hosted in sheared andesites with carbonate replacement or quartz veining and occurs as quartz ± ankerite veinlets or as replacement type in shear zones and is characterised by trace to 10% pyrite with local visible gold. Alteration is dominated by sericite-fuchsite-tourmaline-pyrite.

 

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 In EN 20210803

Long Section Ex EN 20210803

PR_EN_20210803_Surface

PR_EN_20210803_UG