Osisko Windfall Drilling Intercepts Wide High-Grade in Lynx

58.9 g/t Au Over 14.7 Metres

TORONTO, March 29, 2022 (GLOBE NEWSWIRE) — 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 27 intercepts in 8 drill holes (1 from surface, 8 from underground) and 8 wedges. Infill intercepts are located inside defined January 2022 mineral resource estimate (“MRE”) blocks (

see Osisko news release dated January 10,


2022

). Expansion intercepts are located outside the January 2022 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: “The infill program at Windfall continues to intercept high-grade mineralization. Today’s wide headline hole comes from Triple Lynx wireframe 3161 which has another wide zone of

41.4 g/t Au over 9.0 metres

. Infill at Underdog is also returning intercepts of over one ounce per tonne over more than two meters.”

Selected high-grade intercepts include:

58.9 g/t Au over 14.7 metres

in WST-21-0996A;

41.4 g/t Au over 9.0 metres

in WST-21-0928;

88.0 g/t Au over 3.0 metres

in WST-21-0997;

49.8 g/t Au over 3.9 metres

in WST-21-0914;

81.5 g/t Au over 2.0 metres

in WST-21-0936A; and

60.0 g/t Au over 2.4 metres

in OSK-W-21-2463-W3. Maps showing hole locations and full analytical results are available at


www.osiskomining.com


. Maps:

Long Section_In EN 20220329

,

PR_EN_20220329_Surface

,

PR_EN_20220329_UG

.



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-21-1871-W3

816.3

820.7

4.4

22.6

UDD_4101


Underdog


including
816.3 817.0 0.7 86.0

and
820.2 820.7 0.5 60.6

OSK-W-21-2463-W3

971.5

973.9

2.4

60.0

47.1

UDD_4122


Underdog


including
972.8 973.9 1.1 128 100

OSK-W-21-2544-W1

791.7

794.0

2.3

4.13


TLX_3184


Triple Lynx


including
791.7 792.0 0.3 11.6


797.7

800.0

2.3

12.2


TLX_3159


Lynx HW


including
798.3 798.9 0.6 45.3

OSK-W-21-2599

702.8

705.8

3.0

4.83


CA2_2208


Caribou


including
702.8 703.5 0.7 16.6

WST-21-0914

250.1

254.0

3.9

49.8

46.3

LSW_3500


Lynx SW


including
250.1 250.4 0.3 146 100

WST-21-0928

273.1

282.1

9.0

41.4

33.0

TLX_3161


Triple Lynx


including
275.8 277.1 1.3 155 96.5

WST-21-0936A

527.0

529.0

2.0

81.5

25.2

LX4_3450


Lynx 4


including
527.8 528.3 0.5 325 100

WST-21-0996A

146.3

161.0

14.7

58.9

32.2

TLX_3161


Triple Lynx


including
150.6 151.3 0.7 650 100

WST-21-0997

589.0

592.0

3.0

88.0

43.0

LX4_3430


Lynx 4


including
589.7 590.7 1.0 235 100

WST-22-1000

166.0

168.1

2.1

5.82


TLX_3163


Triple Lynx


including
167.2 167.7 0.5 22.1


232.8

235.0

2.2

5.09

TLX_3169

Triple Lynx


256.4

258.6

2.2

4.43

TLX_3175


Triple Lynx


including
256.4 256.9 0.5 18.1


372.3

374.5

2.2

4.03

TLX_3191


Triple Lynx


including
373.7 374.5 0.8 9.19

WST-22-1001

503.4

506.3

2.9

6.60

LX4_3404


Lynx 4


including
505.5 505.8 0.3 19.5

WST-22-1006

186.8

189.0

2.2

35.6

14.8

TLX_3121


Triple Lynx


including
186.8 187.1 0.3 252 100


512.0

518.3

6.3

9.22

LX4_3404


Lynx 4


including
512.3 513.5 1.2 25.7

and
517.8 518.3 0.5 39.4

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See

“Quality Control and Reporting Protocols”

below. CA2= Caribou 2, LX4 = Lynx 4, LSW = Lynx Southwest, 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-21-2540-W3

1280.0

1282.0

2.0

17.7

LX4


Lynx 4


including
1281.4 1282.0 0.6 58.6

OSK-W-21-2540-W9

1192.0

1194.0

2.0

3.68

LX4

Lynx 4


1202.0

1208.0

6.0

7.68

LX4


Lynx 4


including
1207.0 1208.0 1.0 32.9


1230.0

1232.0

2.0

15.3

LX4

Lynx 4


1282.7

1287.8

5.1

4.94

LX4


Lynx 4


including
1287.0 1287.8 0.8 19.3

OSK-W-21-2646-W1

1067.0

1070.0

3.0

3.95

TLX

Triple Lynx

OSK-W-22-2540-W12

867.4

869.5

2.1

6.29

LNX


Lynx


including
868.4 868.7 0.3 39.5

OSK-W-22-2540-W13

879.5

881.8

2.3

7.40

LNX


Lynx


including
879.5 880.4 0.9 18.8


940.0

942.0

2.0

6.01

TLX


Triple Lynx


including
940.0 940.5 0.5 23.3

WST-22-1006

609.0

611.1

2.1

8.40

LX4


Lynx 4


including
609.9 610.6 0.7 24.8

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See

“Quality Control and Reporting Protocols”

below., LNX = Lynx, LX4 = Lynx 4 and TLX = Triple Lynx.



Drill hole location


Hole Number

Azimuth (°)

Dip (°)

Length (m)

UTM E

UTM N

Elevation

Section

OSK-W-21-1871-W3
331 -56 906 452496 5434397 402 2475

OSK-W-21-2463-W3
339 -65 1299 452617 5434447 402 2600

OSK-W-21-2540-W3
117 -60 1470 453465 5435640 410 3925

OSK-W-21-2540-W9
117 -60 1349 453465 5435640 410 3925

OSK-W-21-2544-W1
128 -50 1140 452960 5435539 419 3425

OSK-W-21-2599
328 -62 774 452787 5434526 397 2800

OSK-W-21-2646-W1
109 -58 1236 453326 5435648 413 3800

OSK-W-22-2540-W12
117 -60 885 453465 5435640 410 3925

OSK-W-22-2540-W13
117 -60 911 453465 5435640 410 3925

WST-21-0914
148 -59 502 453105 5435066 231 3325

WST-21-0928
154 -70 391 453507 5435327 -7 3800

WST-21-0936A
137 -48 570 453257 5435209 96 3525

WST-21-0996A
143 -45 427 453358 5435297 -149 3675

WST-21-0997
119 -45 640 453506 5435326 -90 3800

WST-22-1000
139 -45 447 453359 5435297 -149 3675

WST-22-1001
124 -46 637 453506 5435326 -90 3800

WST-22-1006
122 -45 610 453506 5435326 -90 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.


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 in thickness. 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.


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.


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 January 10, 2022 is


supported by the technical report entitled “Mineral Resource Estimate Update for the Windfall Project” dated February 10, 2022 (with an effective date  of October 21, 2021),


and assuming a cut-off grade of 3.50 g/t Au,


comprises 565,000 tonnes at 11.6 g/t Au (210,000 ounces) in the measured mineral resource category, 8,907,000 tonnes at 10.5 g/t Au (2,994,000 ounces) in the indicated mineral resource category and 13,035,000 tonnes at 8.6 g/t Au (3,585,000 ounces) in the inferred mineral resource category


. The key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in the January 10, 2022, news release, certain of which are described in the January 10, 2022, news release, are further described in the full technical report for this updated mineral resource estimate 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 r


esources 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.


T


he 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 2,500 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


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