OSISKO INFILL DRILLING RETURNS HIGH GRADE AT WINDFALL

Including 22.3 g/t Au Over 15.9 Metres

(Toronto, October 8, 2020) Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new analytical results from the ongoing expansion and definition drill program at its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec.

Drilling is currently focused on the Lynx deposit. Osisko Chief Executive Officer John Burzynski commented: “Infill drilling is progressing very well, daily increasing our confidence in the continuity and prevalence of high-grade mineralization at Windfall. Today’s infill results contain 18 intercepts with uncut average grades of over half an ounce per tonne, including the spectacular 22.3 g/t Au over 15.9 metres, showing that Lynx not only has grade but can also deliver width.”

The table below contains resource definition infill intercepts located inside the February 2020 mineral resource estimate wireframes (see Osisko news release dated February 19, 2020). Significant new analytical results are presented below and include 67 intercepts in 26 drill holes and 8 wedges.

Selected high-grade intercepts from the new results include: 314 g/t Au over 3.0 metres in OSK-W-20-2260-W1; 22.3 g/t Au over 15.9 metres in OSK-W-20-2139-W10; 33.6 g/t Au over 9.8 metres in OSK-W-20-2280-W1; 127 g/t Au over 2.3 metres in OSK-W-20-2256; 97.8 g/t Au over 2.5 metres in OSK-W-20-2292-W1; and 53.4 g/t Au over 2.1 metres in OSK-W-20-2252-W4. 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-20-2139-W10 899.0 914.9 15.9 22.3   Lynx_371 Triple Lynx
including 907.1 907.6 0.5 80.2
941.9 944.0 2.1 17.4   Lynx_363 Triple Lynx
OSK-W-20-2197-W2 780.0 782.0 2.0 10.1   Lynx_363 Triple Lynx
including 780.8 781.7 0.9 22.1
OSK-W-20-2252-W2 826.0 828.0 2.0 4.03   Lynx_371 Triple Lynx
833.0 835.0 2.0 4.41   Lynx_371 Triple Lynx
OSK-W-20-2252-W4 880.5 882.6 2.1 53.4 33.2 Lynx_371 Triple Lynx
including 882.0 882.6 0.6 171 100
889.0 892.0 3.0 3.24   Lynx_361 Triple Lynx
902.0 904.0 2.0 41.5   Lynx_361 Triple Lynx
including 903.0 904.0 1.0 82.1
OSK-W-20-2256 852.8 855.0 2.2 44.4 19.7 Lynx_371 Triple Lynx
including 853.2 853.6 0.4 236 100
  881.1 883.4 2.3 127 51.1 Lynx_361 Triple Lynx
including 882.2 882.8 0.6 390 100
894.0 896.2 2.2 4.63   Lynx_361 Triple Lynx
  898.0 900.0 2.0 11.3   Lynx_361 Triple Lynx
  978.9 982.9 4.0 4.44   Lynx_369 Triple Lynx
including 982.2 982.9 0.7 10.5
OSK-W-20-2256-W4 930.0 934.0 4.0 5.63   Lynx_364 Triple Lynx
963.0 965.0 2.0 19.3   Lynx_369 Triple Lynx
including 964.0 964.5 0.5 76.4
OSK-W-20-2260-W1 843.0 846.0 3.0 314 38.0 Lynx_361 Triple Lynx
including 843.4 844.4 1.0 927 100
OSK-W-20-2272 613.0 615.0 2.0 3.45   Lynx_356 Lynx
OSK-W-20-2275 796.0 798.0 2.0 4.38   Lynx_365 Triple Lynx
including 796.0 796.6 0.6 11.3
837.0 839.2 2.2 23.4 22.8 Lynx_365 Triple Lynx
including 837.7 838.2 0.5 102 100
OSK-W-20-2280 1003.7 1006.3 2.6 4.94   Lynx_368 Triple Lynx
including 1003.7 1004.0 0.3 11.1
and 1004.0 1004.4 0.4 10.5
1025.9 1030.1 4.2 8.13   Lynx_363 Triple Lynx
including 1027.0 1027.5 0.5 25.5
1038.0 1040.0 2.0 3.76   Lynx_363 Triple Lynx
including 1039.4 1040.0 0.6 8.10
1067.0 1069.0 2.0 12.5   Lynx_364 Triple Lynx
including 1067.8 1068.1 0.3 52.1
  1079.0 1081.0 2.0 4.09   Lynx_364 Triple Lynx
  1088.7 1094.4 5.7 16.8 12.9 Lynx_369 Triple Lynx
including 1093.2 1093.5 0.3 173 100
1109.0 1111.0 2.0 4.64   Lynx_370 Triple Lynx
OSK-W-20-2280-W1 1006.0 1008.0 2.0 4.22   Lynx_368 Triple Lynx
including 1006.0 1007.0 1.0 8.08
  1013.0 1016.0 3.0 4.82   Lynx_368 Triple Lynx
  1021.9 1024.1 2.2 20.3   Lynx_363 Triple Lynx
  1043.4 1047.6 4.2 27.7   Lynx_363 Triple Lynx
including 1043.7 1044.7 1.0 78.6
  1080.8 1083.0 2.2 4.81   Lynx_364 Triple Lynx
  1097.0 1106.8 9.8 33.6 27.6 Lynx_370 Triple Lynx
including 1102.0 1104.0 2.0 129 100
and 1106.5 1106.8 0.3 108 100
OSK-W-20-2288 624.4 633.9 9.5 12.0   Lynx_356 Lynx
including 629.4 630.0 0.6 27.9
and 632.7 633.3 0.6 28.8
OSK-W-20-2292 852.0 854.0 2.0 3.87   Lynx_363 Triple Lynx
including 852.0 852.7 0.7 10.9
OSK-W-20-2292-W1 835.9 838.0 2.1 3.39   Lynx_361 Triple Lynx
840.0 843.5 3.5 3.65   Lynx_361 Triple Lynx
including 840.0 840.4 0.4 7.83
and 843.0 843.5 0.5 9.84
857.0 859.3 2.3 26.0   Lynx_363 Triple Lynx
including 858.3 859.3 1.0 57.6
889.5 892.0 2.5 97.8 32.2 Lynx_364 Triple Lynx
including 890.3 891.1 0.8 305 100
OSK-W-20-2293 139.9 142.4 2.5 5.25   F17_6005 F-17
including 142.0 142.4 0.4 18.0
OSK-W-20-2297 128.0 131.0 3.0 29.3 24.2 F17_6003 F-17
including 128.0 128.4 0.4 138 100
166.5 168.8 2.3 5.82   F17_6005 F-17
OSK-W-20-2300 149.7 154.0 4.3 7.42   F17_6005 F-17
including 151.0 152.0 1.0 15.6
OSK-W-20-2312 126.0 128.0 2.0 7.26   Mallard_5200 Mallard
including 127.0 127.6 0.6 22.6
OSK-W-20-2315 127.0 129.0 2.0 5.59   Mallard_5200 Mallard
157.0 159.0 2.0 4.13   Mallard_5213 Mallard
OSK-W-20-2321 166.3 168.5 2.2 6.40   Mallard_5213 Mallard
including 167.2 167.8 0.6 21.2
OSK-W-20-2323 153.0 155.0 2.0 3.88   Mallard_5213 Mallard
including 154.7 155.0 0.3 24.1
OSK-W-20-2327 105.3 111.4 6.1 13.6   Mallard_5213 Mallard
including 109.0 110.0 1.0 48.9
WST-20-0135 72.0 74.3 2.3 4.20   Lynx_311 Lynx
including 73.9 74.3 0.4 14.6
WST-20-0318 65.0 68.5 3.5 36.2   Lynx_311 Lynx
including 66.0 66.7 0.7 91.0
WST-20-0389A 192.0 194.3 2.3 9.23   Lynx_341 Lynx
including 192.0 192.6 0.6 23.5
553.9 555.9 2.0 3.44   Lynx_340 Lynx
including 553.9 554.3 0.4 15.7
WST-20-0391A 91.6 94.1 2.5 6.21   Lynx_304 Lynx
including 93.4 94.1 0.7 17.6
98.3 100.5 2.2 3.47   Lynx_304 Lynx
WST-20-0392 82.8 84.8 2.0 8.12   Lynx_323 Lynx
including 83.4 83.8 0.4 26.3
  88.0 90.2 2.2 5.49   Lynx_323 Lynx
  107.0 109.7 2.7 11.2   Lynx_304 Lynx
including 108.4 108.8 0.4 70.9
WST-20-0393 48.9 51.5 2.6 4.68   Lynx_325 Lynx
including 50.0 50.7 0.7 10.2
113.2 115.9 2.7 5.34   Lynx_304 Lynx
including 114.3 114.8 0.5 18.8
WST-20-0402 142.1 144.4 2.3 25.8 14.3 Lynx_301 Lynx
including 142.1 142.4 0.3 189 100
WST-20-0409 85.4 87.4 2.0 3.37   Lynx_323 Lynx
WST-20-0412 97.6 99.9 2.3 9.21   Lynx_323 Lynx
including 99.6 99.9 0.3 48.5
WST-20-0421 87.6 90.0 2.4 3.87   Lynx_323 Lynx
including 88.2 88.5 0.3 28.3
151.0 153.2 2.2 4.96   Lynx_321 Lynx
including 152.3 153.2 0.9 11.2
WST-20-0423 101.0 103.7 2.7 5.56   Lynx_304 Lynx
109.0 112.0 3.0 9.95   Lynx_359 Lynx
WST-20-0424 115.0 117.0 2.0 8.3   Lynx_359 Lynx
including 116.0 117.0 1.0 15.4

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

Drill hole location

Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-20-2139-W10 115 -52 1212 452980 5435549 420 3450
OSK-W-20-2197-W2 121 -48 1064 453087 5435526 417 3550
OSK-W-20-2252-W2 129 -54 1194 453241 5435694 415 3750
OSK-W-20-2252-W4 129 -54 1143 453241 5435694 415 3750
OSK-W-20-2256 125 -51 1179 453160 5435686 414 3675
OSK-W-20-2256-W4 125 -51 1122 453160 5435686 414 3675
OSK-W-20-2260-W1 127 -48 1140 453201 5435667 413 3700
OSK-W-20-2272 149 -45 1004 452967 5435265 412 3300
OSK-W-20-2275 127 -49 1094 452886 5435584 409 3400
OSK-W-20-2280 127 -58 1161 453304 5435639 415 3775
OSK-W-20-2280-W1 127 -58 1170 453304 5435639 415 3775
OSK-W-20-2288 146 -51 749 452875 5435181 409 3175
OSK-W-20-2292 125 -54 1059 453037 5435563 420 3525
OSK-W-20-2292-W1 125 -54 1149 453037 5435563 420 3525
OSK-W-20-2293 145 -44 183 452658 5435549 406 3175
OSK-W-20-2297 149 -47 180 452652 5435567 405 3175
OSK-W-20-2300 152 -45 192 452699 5435578 406 3225
OSK-W-20-2312 334 -51 192 451964 5434816 408 2225
OSK-W-20-2315 334 -52 192 451979 5434805 407 2225
OSK-W-20-2321 332 -51 176 451958 5434790 407 2200
OSK-W-20-2323 335 -49 171 451936 5434791 405 2175
OSK-W-20-2327 334 -49 132 451901 5434810 401 2150
WST-20-0135 187 -58 444 453226 5435125 134 3475
WST-20-0318 148 -52 502 453228 5435127 134 3475
WST-20-0389A 115 -46 616 453452 5435266 115 3725
WST-20-0391A 135 8 174 453359 5435209 155 3625
WST-20-0392 126 2 181 453359 5435209 155 3625
WST-20-0393 153 -37 175 453358 5435208 154 3625
WST-20-0402 147 32 162 453493 5435287 119 3775
WST-20-0409 155 21 169 453450 5435264 117 3725
WST-20-0412 164 24 165 453450 5435264 117 3725
WST-20-0421 162 16 168 453450 5435264 117 3725
WST-20-0423 134 -18 142 453359 5435209 154 3625
WST-20-0424 160 5 178 453358 5435208 155 3625

 

Lynx Zone

Mineralization occurs as grey to translucent quartz-carbonate-pyrite-tourmaline veins and pyrite replacement zones and stockworks. The vein-type 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-Zone

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

 

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), Project Manager of Osisko’s Windfall Lake 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. All NQ core assays reported 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, Thunder Bay, Ontario, Sudbury, Ontario or Vancouver, British Colombia, or (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 an Aqua Regia-ICP-AES method at ALS Laboratories. Drill program design, QualityAssurance/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 Eeyou Istchee James Bay, Québec, Canada. The mineral resource defined by Osisko, as disclosed in the news release dated February 19, 2020 and supported by the technical report entitled “An updated mineral resource estimate for the Windfall Lake Project, Located in the Abitibi Greenstone Belt, Urban Township, Eeyou Istchee James Bay, Québec, Canada” and dated April 3, 2020 (with an effective date of January 3, 2020), and assuming a cut-off grade of 3.5 g/t, comprises 4,127,000 tonnes at 9.1 g/t Au (1,206,000 ounces) in the indicated mineral resource category and 14,532,000 tonnes at 8.40 g/t Au (3,938,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in the February 19,2020 news release are further described in the full technical report prepared by Micon International Limited (“Micon”) and BBA Inc (“BBA”), in accordance with NI 43-101 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 deformed sub-vertical zones plunging to the northeast. Vein-type or pyrite replacement-type styles of mineralization crosscut syn-volcanic host rocks and syn-deformation felsic porphyry intrusions and are spatially associated with the contacts of the intrusions. The deposit is well defined from surface to a depth of 1,200 metres and remains open along strike and at depth.Mineralization has been identified 30 metres from surface in some areas and as deep as 2,000 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 precious metal 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 a100% 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; the prospects, if any, of the Windfall gold deposit; the timing and ability of Osisko, if at all, to publish a feasibility study for the Windfall gold deposit; the projected capital expenditures of mining activities at the Windfall gold deposit; upgrading an inferred mineral resource to a measured mineral resource or indicated mineral resource category; future drilling at the Windfall gold deposit; the deposit remaining open along strike to the northeast and at depth; significant high-grade zones (Lynx 4, Triple Lynx) remaining open down plunge; the plunge potential of the Lynx and Underdog zones; 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 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