Osisko Infill and Expansion Drilling Hits More High-Grade



124 g/t Au Over 2.7 Metres in Triple Lynx




78.7 g/t




Au over 2.0 metres in Lynx SW

TORONTO, May 04, 2021 (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 52 intercepts in 35 drill holes (9 from surface, 15 from underground) and 11 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 highlighted intercepts in the Lynx and Triple Lynx zones, as seen on the accompanying long sections available on our website, demonstrate the continued distribution of high-grade intersected throughout these areas in both infill and expansion drilling.”

Selected high-grade intercepts include:

124 g/t Au over


2.7


metres

in WST-21-0729;

78.7 g/t


Au over 2.0 metres

and

39.3 g/t Au over 2.2 metres

in WST-21-0703,

34.6 g/t Au


over 3.6 metres

in OSK-W-21-2465,

41.6 g/t Au


over 2.9 metres

in WST-21-0696,

41.9 g/t Au over 2.1 metres

in WST-21-0652,

31.5 g/t Au over 2.4 metres

in OSK-W-21-2472 and

37.1 g/t Au over 2.0 metres

in WST-21-0749. 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-20-2252-W11

851.0

853.0

2.0

3.99

TLX_3189

Triple Lynx

OSK-W-20-2283-W2

789.6

791.8

2.2

4.14

TLX_3171


Triple Lynx


including
790.9 791.2 0.3 18.5

OSK-W-21-2394-W4

643.2

646.2

3.0

9.31

TLX_3171


Triple Lynx


including
643.2 643.6 0.4 18.8

OSK-W-21-2394-W6

674.6

676.7

2.1

10.7

TLX_3171


Triple Lynx


including
675.1 676.0 0.9 21.7


694.0

696.0

2.0

4.57

TLX_3184

Triple Lynx

OSK-W-21-2436-W3

805.0

807.0

2.0

21.4

20.4

LX4_3437


Lynx 4


including
806.6 807.0 0.4 105 100

OSK-W-21-2445-W3

601.6

605.1

3.5

3.68

TLX_3171

Triple Lynx

OSK-W-21-2470

976.0

978.0

2.0

4.62

TLX_3163

Triple Lynx

OSK-W-21-2478

887.0

889.2

2.2

8.94

TLX_3184


Triple Lynx


including
887.8 888.2 0.4 44.7

OSK-W-21-2492

775.0

777.5

2.5

17.2

LX4_3414


Lynx 4


including
776.9 777.5 0.6 42.9


783.9

786.2

2.3

22.4

20.9

LX4_3414


Lynx 4


including
784.8 785.2 0.4 109 100

OSK-W-21-2495

659.0

661.0

2.0

3.65

LXM_3304


Lynx


including
659.4 659.7 0.3 20.9

WST-21-0652

336.0

338.1

2.1

41.9

22.1

LXSW_3556


Lynx


including
337.7 338.1 0.4 204 100

WST-21-0658

185.0

187.1

2.1

15.7

TLX_3161


Triple Lynx


including
185.0 185.6 0.6 51.3

WST-21-0671A

171.0

173.0

2.0

25.0

LXM_3304


Lynx


including
171.0 172.0 1.0 43.6

WST-21-0675

159.2

161.4

2.2

14.2

LXM_3304


Lynx


including
159.2 159.9 0.7 39.4

WST-21-0676

152.7

155.1

2.4

3.93

LXM_3304


Lynx


including
152.7 153.3 0.6 10.4

WST-21-0677

399.0

401.0

2.0

8.52

TLX_3165

Triple Lynx


409.5

411.5

2.0

11.4

TLX_3165


Triple Lynx


including
410.5 411.0 0.5 28.8

WST-21-0692

334.2

336.4

2.2

5.34

TLX_3131

Triple Lynx

WST-21-0698

138.3

140.3

2.0

10.3

LXM_3334

Lynx

WST-21-0703

252.0

256.2

4.2

11.6

LXSW_3506


Lynx


including
255.1 255.5 0.4 66.5


463.7

465.9

2.2

39.3

28.1

LXSW_3502


Lynx


including
464.7 465.3 0.6 141 100

WST-21-0729

304.9

307.6

2.7

124

23.5

TLX_3166


Triple Lynx


including
305.9 306.3 0.4 780 100

WST-21-0739

128.2

130.2

2.0

23.5

LXM_3304


Lynx


including
129.0 129.7 0.7 63.8

WST-21-0749

144.9

146.9

2.0

37.1

LXM_3304

Lynx


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 LXSW = Lynx Southwest.



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-21-2394-W6

914.0

916.0

2.0

5.70

TLX_3195


Triple Lynx


including
914.8 915.2 0.4 27.2

OSK-W-21-2436-W2

614.2

617.0

2.8

7.16

Lynx 4

Lynx

OSK-W-21-2445-W1

878.0

880.0

2.0

4.68

Triple Lynx

Triple Lynx

OSK-W-21-2445-W2

618.2

620.6

2.4

4.22

Triple Lynx

Triple Lynx

OSK-W-21-2445-W4

918.5

920.5

2.0

16.9

Triple Lynx


Triple Lynx


including
918.5 919.5 1.0 32.0

OSK-W-21-2465

919.0

921.0

2.0

8.88

Lynx 4

Lynx


951.4

955.0

3.6

34.6

Lynx 4


Lynx


including
952.0 954.0 2.0 54.3

OSK-W-21-2465

962.5

964.6

2.1

12.4

Lynx 4

Lynx

OSK-W-21-2470

1020.9

1023.0

2.1

6.37

Triple Lynx


Triple Lynx


including
1021.8 1022.1 0.3 39.1


1178.0

1180.1

2.1

5.63

Triple Lynx


Triple Lynx


including
1179.2 1180.1 0.9 12.9

OSK-W-21-2470-W1

963.0

968.0

5.0

10.8

Triple Lynx


Triple Lynx


including
963.0 964.0 1.0 41.4


987.0

989.0

2.0

27.7

27.6

Triple Lynx


Triple Lynx


including
987.3 987.7 0.4 101 100

OSK-W-21-2472

731.8

734.2

2.4

31.5

LX4_3437


Lynx 4


including
733.4 734.2 0.8 78.3


781.1

783.9

2.8

11.2

Lynx 4


Lynx


including
783.1 783.9 0.8 31.8

OSK-W-21-2473

625.6

630.0

4.4

10.0

Lynx


Lynx


including
625.6 626.2 0.6 49.1

OSK-W-21-2478

1117.0

1119.0

2.0

7.22

Triple Lynx

Triple Lynx

OSK-W-21-2482

782.0

784.0

2.0

11.7

Triple Lynx


Triple Lynx


including
782.0 782.9 0.9 26.0

OSK-W-21-2489

1005.0

1007.0

2.0

8.26

Triple Lynx

Triple Lynx

WST-21-0652

216.0

218.0

2.0

4.15

Lynx SW

Lynx SW


448.0

450.0

2.0

4.35

Lynx SW


Lynx SW


including
448.7 449.2 0.5 15.6

WST-21-0657

442.3

444.3

2.0

4.26

Triple Lynx

Triple Lynx

WST-21-0696

370.7

373.6

2.9

41.6

36.7

Triple Lynx


Triple Lynx


including
371.8 372.7 0.9 116 100


464.0

466.0

2.0

5.62

Lynx 4

Lynx

WST-21-0703

43.2

45.2

2.0

78.7

37.1

Lynx SW


Lynx SW


including
43.5 44.2 0.7 219 100

WST-21-0706

314.5

316.9

2.4

14.1

Lynx SW


Lynx SW


including
315.3 315.9 0.6 54.1

WST-21-0729

174.3

177.6

3.3

8.95

Lynx

Lynx


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

“Quality Control and Reporting Protocols”

below. TLX = Triple Lynx, LX4 = Lynx 4, and SW = Southwest.



Drill hole location


Hole Number

Azimuth (°)

Dip (°)

Length (m)

UTM E

UTM N

Elevation

Section

OSK-W-20-2252-W11
129 -54 1191 453241 5435694 415 3750

OSK-W-20-2283-W2
135 -50 1011 452997 5435607 425 3500

OSK-W-21-2394-W4
138 -52 920 452923 5435467 414 3375

OSK-W-21-2394-W6
138 -52 978 452923 5435467 414 3375

OSK-W-21-2436-W2
130 -57 789 453709 5435618 400 4125

OSK-W-21-2436-W3
130 -57 879 453709 5435618 400 4125

OSK-W-21-2445-W1
141 -50 909 452906 5435433 415 3325

OSK-W-21-2445-W2
141 -50 822 452906 5435433 415 3325

OSK-W-21-2445-W3
141 -50 753 452906 5435433 415 3325

OSK-W-21-2445-W4
141 -50 944 452906 5435433 415 3325

OSK-W-21-2465
123 -61 1253 453397 5435557 413 3825

OSK-W-21-2470
132 -59 1230 453304 5435639 415 3775

OSK-W-21-2470-W1
132 -59 1227 453304 5435639 415 3775

OSK-W-21-2472
12 -72 900 454135 5435058 397 4225

OSK-W-21-2473
123 -56 1272 453420 5435610 413 3875

OSK-W-21-2478
128 -54 1257 452997 5435607 425 3500

OSK-W-21-2482
131 -57 939 453009 5435387 413 3400

OSK-W-21-2489
133 -54 1140 453121 5435509 419 3550

OSK-W-21-2492
122 -53 870 453687 5435676 401 4125

OSK-W-21-2495
123 -54 1257 453426 5435565 410 3850

WST-21-0652
128 -60 481 452955 5435003 253 3175

WST-21-0657
141 -56 448 453357 5435272 16 3650

WST-21-0658
137 -49 255 453357 5435272 16 3650

WST-21-0671A
142 -51 372 453507 5435327 -7 3800

WST-21-0675
133 -40 336 453508 5435327 -7 3800

WST-21-0676
129 -32 318 453508 5435327 -7 3800

WST-21-0677
144 -42 652 453257 5435209 96 3525

WST-21-0692
157 -54 541 453356 5435272 16 3650

WST-21-0696
137 -49 492 453229 5435127 134 3475

WST-21-0698
167 -40 160 453356 5435272 16 3650

WST-21-0703
146 -60 489 453104 5435065 231 3325

WST-21-0706
165 -54 417 453104 5435065 231 3325

WST-21-0729
132 -49 510 453229 5435127 135 3475

WST-21-0739
164 -37 195 453507 5435326 -7 3800

WST-21-0749
136 -30 196 453357 5435272 16 3650


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 3.0 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 defined by Osisko, as disclosed in the news release dated February 17, 2021 and


supported by the technical report entitled “Mineral Resource Estimate Update for the Windfall Project, Eeyou Istchee James Bay, Québec, Canada” dated March 8, 2021 (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 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 2,700 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



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