Osisko Step-out Drilling Expands High Grade at Windfall

Including 391 g/t Au Over 2.4 Metres in Triple Lynx

TORONTO, Oct. 07, 2020 (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.

Drilling is currently focused on the Lynx deposit. Osisko Chief Executive Officer John Burzynski commented: “Windfall continues to grow in scale with impressive results flowing in from the Lynx deposit. Today’s new intersections are all from outside the published resource area and include 15 intercepts with uncut average grades of over one oz/t. The ongoing expansion drilling continues to show the incredible upside growth potential of our deposit.”

The table below shows intercepts located outside the February 2020 mineral resource estimate wireframes (

see Osisko news release


dated


February 19, 2020

). These intercepts either expand the resource wireframes or are located in a defined zone/corridor but not yet correlated to a specific wireframe. Significant new analytical results are presented below and include 110 intercepts in 43 drill holes and 24 wedges.

Selected high-grade intercepts from the new results include:

391 g/t Au over 2.4 metres


,

70 metres toward surface from wireframe Lynx_361, in OSK-W-20-2133-W2;

142 g/t Au over 2.3 metres

in OSK-W-20-2307;

86.0 g/t Au over 2.1 metres

in WST-20-0341A;

73.8 g/t Au over 2.0 metres

in WST-20-0470;

54.4 g/t Au over 4.8 metres

in OSK-W-20-2252-W2; and

49.8 g/t Au over 2.2 metres

in OSK-W-20-2292. Maps showing hole locations and full analytical results are available at

www.osiskomining.com



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-17-1258

971.7

973.7

2.0

3.33


Lynx 4


Lynx


including
971.7 972.7 1.0 6.56

OSK-W-18-1727

782.9

784.9

2.0

12.7


Lynx

Lynx

OSK-W-19-1857-W11

1301.8

1304.6

2.8

7.39


Lynx 4

Lynx

OSK-W-19-2100-W4

1212.5

1214.7

2.2

5.22


Triple Lynx

Triple Lynx

1242.0

1244.0

2.0

6.47


Triple Lynx

Triple Lynx

OSK-W-19-2101

664.4

667.0

2.6

5.48


Triple Lynx

Triple Lynx

OSK-W-20-2133-W2

783.6

786.0

2.4

391

31.1

Lynx_361


Triple Lynx


including
784.2 784.6 0.4 2260 100

OSK-W-20-2139-W7

1081.0

1083.5

2.5

9.53


Triple Lynx


Triple Lynx


including
1081.0 1081.9 0.9 26.1

OSK-W-20-2139-W8

543.0

545.0

2.0

6.68


Triple Lynx


Triple Lynx


including
543.5 544.4 0.9 14.5

OSK-W-20-2139-W10

1196.0

1198.0

2.0

11.7


Triple Lynx


Triple Lynx


including
1196.0 1197.1 1.1 21.3

OSK-W-19-2169

893.9

895.9

2.0

5.59


Lynx 4


Lynx


including
894.7 895.3 0.6 18.2

1256.3

1258.4

2.1

15.8


Lynx 4


Lynx


including
1257.5 1258.4 0.9 36.2

OSK-W-20-2170-W6

1384.0

1386.4

2.4

6.7


0


Lynx 4

Lynx

OSK-W-19-2173

29.0

31.0

2.0

3.07


F11

F11

OSK-W-19-2177

200.0

202.0

2.0

3.1


0


F11

F11

OSK-W-20-2197-W2

768.7

771.4

2.7

10.3


Lynx_361


Triple Lynx


including
769.7 770.7 1.0 26.0

1045.0

1047.0

2.0

5.66


Lynx 4

Lynx

OSK-W-20-2217-W2

860.0

862.0

2.0

14


.0


Triple Lynx


Triple Lynx


including
860.0 860.5 0.5 55.6

OSK-W-20-2217-W3

830.0

832.3

2.3

7.53


Lynx_363


Triple Lynx


including
831.0 831.4 0.4 26.8

1111.7

1114.0

2.3

16.4


Triple Lynx


Triple Lynx


including
1113.5 1114.0 0.5 66.3

OSK-W-20-2249

730.0

732.0

2.0

5.66


Lynx SW


Lynx


including
730.5 730.9 0.4 22.8

OSK-W-20-2250

1002.2

1005.0

2.8

18.1

15.6

Triple Lynx


Triple Lynx


including
1002.2 1002.5 0.3 123 100

OSK-W-20-2250-W1

1009.0

1011.1

2.1

5.08


Triple Lynx

Triple Lynx

OSK-W-20-2250-W2

1024.7

1028.0

3.3

28.8


Triple Lynx


Triple Lynx


including
1026.4 1027.0 0.6 63.0

OSK-W-20-2250-W3

714.0

716.5

2.5

14.7


Triple Lynx

Triple Lynx

OSK-W-20-2250-W4

727.7

734.5

6.8

4.58


Triple Lynx


Triple Lynx


including
727.7 728.4 0.7 10.3

and
730.5 731.0 0.5 12.0

855.4

858.0

2.6

6.29


Triple Lynx


Triple Lynx


including
857.2 858.0 0.8 18.6

OSK-W-20-2252-W2

812.0

814.0

2.0

7.64


Triple Lynx

Triple Lynx

817.2

822.0

4.8

54.4

10.4

Triple Lynx


Triple Lynx


including
817.2 817.5 0.3 804 100

OSK-W-20-2252-W3

824.3

829.7

5.4

3.58


Triple Lynx

Triple Lynx

845.1

847.1

2.0

4.01


Triple Lynx

Triple Lynx

OSK-W-20-2253

387.5

389.5

2.0

4.3


0


Caribou Corridor

Caribou

OSK-W-20-2256

870.0

872.8

2.8

9.81


Triple Lynx

Triple Lynx

OSK-W-20-2256-W2

815.0

817.0

2.0

3.17


Triple Lynx

Triple Lynx

OSK-W-20-2260-W2

1091.0

1093.0

2.0

6.47


Triple Lynx


Triple Lynx


including
1091.4 1092.1 0.7 18.1

1174.4

1176.5

2.1

9.43


Triple Lynx


Triple Lynx


including
1176.0 1176.5 0.5 28.0

OSK-W-20-2263

94.0

96.0

2.0

8.58


Bobcat


Bobcat


including
94.0 95.0 1.0 16.9

106.7

108.8

2.1

6.12


Bobcat


Bobcat


including
108.0 108.8 0.8 14.1

710.0

712.0

2.0

42.6

21.4

Lynx SW


Lynx


including
711.2 711.6 0.4 206 100

OSK-W-20-2266

1027.4

1029.5

2.1

5.58


Triple Lynx


Triple Lynx


including
1028.7 1029.0 0.3 33.1

OSK-W-20-2266-W1

776.8

779.2

2.4

5.73


Triple Lynx


Triple Lynx


including
778.0 779.2 1.2 11.1

797.3

799.3

2.0

3.08


Lynx_364

Triple Lynx

OSK-W-20-2266-W2

717.4

719.4

2.0

19.9


Lynx_363

Triple Lynx

OSK-W-20-2267

50.4

52.8

2.4

15.4


Bobcat


Bobcat


including
51.0 51.5 0.5 46.4

OSK-W-20-2268-W1

737.1

739.3

2.2

7.46


Triple Lynx


Triple Lynx


including
738.3 739.0 0.7 19.0

819.0

821.3

2.3

27.4


Triple Lynx


Triple Lynx


including
819.0 820.0 1.0 45.7

1027.0

1029.0

2.0

6.7


0


Triple Lynx


Triple Lynx


including
1027.4 1028.2 0.8 16.5

OSK-W-20-2268-W2

999.0

1001.0

2.0

5.08


Triple Lynx

Triple Lynx

OSK-W-20-2269

97.3

99.5

2.2

8.21


Bobcat


Bobcat


including
98.0 98.4 0.4 30.8

518.2

520.6

2.4

3.37


Lynx SW

Lynx

886.0

888.0

2.0

14


.0


Lynx SW


Lynx


including
886.5 886.8 0.3 92.5

OSK-W-20-2271

809.6

815.2

5.6

6.69


Lynx


Lynx


including
814.2 815.2 1.0 17.4

841.1

843.1

2.0

18.2


Lynx


Lynx


including
842.1 843.1 1.0 35.0

877.0

879.0

2.0

5.36


Lynx


Lynx


including
877.9 878.2 0.3 27.8

OSK-W-20-2272

683.0

685.1

2.1

13


.0


Triple Lynx


Triple Lynx


including
683.0 683.9 0.9 29.7

OSK-W-20-2273

706.7

708.7

2.0

8.32


Lynx_363


Triple Lynx


including
706.7 707.2 0.5 22.4

1013.8

1017.3

3.5

4.78


Triple Lynx


Triple Lynx


including
1015.1 1015.5 0.4 16.1

OSK-W-20-2280

1013.2

1016.7

3.5

5.23


Triple Lynx


Triple Lynx


including
1013.8 1014.2 0.4 26.7

and
1016.4 1016.7 0.3 11.3

1084.7

1087.0

2.3

4.27


Triple Lynx

Triple Lynx

OSK-W-20-2280-W1

1090.0

1092.0

2.0

11.8


Triple Lynx

Triple Lynx

OSK-W-20-2282

308.4

310.8

2.4

6.13


Bobcat


Bobcat


including
309.0 309.5 0.5 16.6

OSK-W-20-2283

808.0

813.4

5.4

33.5

29


.0

Triple Lynx


Triple Lynx


including
810.8 811.3 0.5 73.1

and
811.7 812.0 0.3 182 100

819.0

821.0

2.0

7.27


Triple Lynx


Triple Lynx


including
819.6 820.0 0.4 24.1

823.2

825.5

2.3

4.3


0


Triple Lynx


Triple Lynx


including
823.6 824.4 0.8 10.6

1001.0

1003.2

2.2

44.8

23.6

Triple Lynx


Triple Lynx


including
1002.7 1003.2 0.5 194 100

1018.0

1020.0

2.0

19.3


Triple Lynx


Triple Lynx


including
1018.9 1019.5 0.6 54.4

OSK-W-20-2288

467.0

469.8

2.8

8.13


Lynx SW


Lynx


including
467.0 467.4 0.4 38.9

OSK-W-20-2292

390.0

392.0

2.0

7.18


Lynx


Lynx


including
391.7 392.0 0.3 19.3

835.4

837.8

2.4

4.47


Triple Lynx

Triple Lynx

845.0

847.0

2.0

11.8


Lynx_361


Triple Lynx


including
845.8 846.3 0.5 41.0

882.0

884.0

2.0

8.01


Lynx_364


Triple Lynx


including
883.0 884.0 1.0 15.7

1007.2

1009.2

2.0

49.8

21

Lynx_372


Triple Lynx


including
1008.8 1009.2 0.4 244 100

OSK-W-20-2295

651.2

658.0

6.8

12.4


Triple Lynx


Triple Lynx


including
652.4 652.7 0.3 28.7

and
653.4 654.0 0.6 45.9

and
656.1 656.7 0.6 56.9

891.7

893.7

2.0

11.6


Lynx SW


Triple Lynx


including
891.7 892.7 1.0 23.0

OSK-W-20-2295-W1

648.6

651.4

2.8

45.1

30.1

Triple Lynx


Triple Lynx


including
650.0 650.7 0.7 160 100

OSK-W-20-2298

169.0

171.7

2.7

7.41


Bobcat


Bobcat


including
169.0 169.7 0.7 20.2

245.0

247.0

2.0

6.59


Bobcat


Bobcat


including
245.0 245.7 0.7 18.4

373.0

375.0

2.0

16.7


Lynx SW


Lynx


including
373.8 374.3 0.5 65.2

OSK-W-20-2305

630.8

635.0

4.2

4.47


Triple Lynx


Triple Lynx


including
634.0 635.0 1.0 9.32

876.0

878.3

2.3

10.7


Triple Lynx


Triple Lynx


including
877.6 878.3 0.7 31.6

882.2

884.6

2.4

43


.0

18


.0

Triple Lynx


Triple Lynx


including
883.4 883.8 0.4 250 100

OSK-W-20-2306

137.8

140.0

2.2

4.3


0


Bobcat

Bobcat

147.1

149.4

2.3

3.12


Bobcat

Bobcat

275.0

277.3

2.3

8.58


Bobcat


Bobcat


including
275.8 276.5 0.7 20.7

386.1

388.3

2.2

3.94


Lynx SW


Lynx


including
386.6 387.0 0.4 11.5

OSK-W-20-2307

689.6

691.9

2.3

142

75.8

Lynx_341


Lynx


including
690.0 690.4 0.4 413 100

OSK-W-20-2310

69.7

72.0

2.3

35.6

13.8

Mallard_5200


Mallard


including
70.8 71.1 0.3 267 100

OSK-W-20-2312

85.0

87.3

2.3

7.19


Mallard


Mallard


including
85.7 86.2 0.5 25.4

OSK-W-20-2324

90.0

92.5

2.5

8.43


Mallard

Mallard

WST-20-0135

293.0

295.1

2.1

35.1

19.2

Lynx SW


Lynx


including
293.7 294.1 0.4 184 100

351.8

354.7

2.9

3.15


Lynx SW


Lynx


including
351.8 352.3 0.5 8.55

and
354.1 354.7 0.6 7.76

360.4

362.6

2.2

13.4


Triple Lynx


Triple Lynx


including
360.4 361.4 1.0 28.9

397.3

399.4

2.1

23.6

14.5

Lynx SW


Lynx


including
397.8 398.1 0.3 164 100

WST-20-0318

377.4

379.6

2.2

8.05


Lynx SW

Lynx

463.3

466.0

2.7

9.06


Lynx 4

Lynx

WST-20-0339

199.1

202.2

3.1

4.57


Lynx HW

Lynx

WST-20-0341A

306.1

308.2

2.1

86


.0

19.9

Lynx SW


Lynx


including
306.1 306.5 0.4 447 100

346.1

348.1

2.0

10.6


Lynx SW


Lynx


including
347.3 347.7 0.4 50.2

WST-20-0345

361.7

363.9

2.2

3.75


Caribou corridor


Caribou


including
362.3 363.1 0.8 9.43

WST-20-0400

158.0

160.2

2.2

11.2


Lynx_301


Lynx


including
159.0 160.2 1.2 19.7

WST-20-0411

148.2

150.4

2.2

38.1

36.1

Lynx HW


Lynx


including
149.2 149.9 0.7 107 100

WST-20-0412

155.0

157.2

2.2

3.06


Lynx_328


Lynx


including
156.9 157.2 0.3 11.2

WST-20-0417

190.6

192.6

2.0

22.4


Lynx


Lynx


including
190.6 191.2 0.6 41.5

428.2

430.2

2.0

4.06


Lynx 4

Lynx

WST-20-0423

125.0

127.0

2.0

5.23


Lynx


Lynx


including
125.0 125.7 0.7 14.9

WST-20-0459

204.3

206.4

2.1

20.6


Lynx SW


Lynx


including
205.9 206.4 0.5 76.2

WST-20-0462

171.0

173.0

2.0

40.4


Lynx


Lynx


including
171.5 172.5 1.0 79.1

454.0

456.0

2.0

3.5


0


Lynx_336


Lynx


including
454.0 454.8 0.8 8.19

638.9

643.2

4.3

3.82


Lynx


Lynx


including
638.9 639.6 0.7 12.6

WST-20-0470

86.2

88.2

2.0

73.8

15


.0

Lynx


Lynx


including
87.5 87.8 0.3 492 100

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-17-1258
126 -51 1128 452972 5435211 416 3275

OSK-W-18-1727
331 -61 810 453461 5435040 396 3625

OSK-W-19-1857-W11
108 -58 1385 453525 5435704 405 4000

OSK-W-19-2100-W4
122 -47 1260 453095 5435726 423 3650

OSK-W-19-2101
18 -68 909 453426 5434779 396 3475

OSK-W-19-2169
130 -50 1268 453215 5435512 410 3650

OSK-W-19-2173
156 -46 234 452182 5435722 407 2850

OSK-W-19-2177
153 -51 396 452454 5435997 406 3225

OSK-W-20-2133-W2
118 -49 1139 453080 5435531 417 3525

OSK-W-20-2139-W7
115 -52 1164 452980 5435549 420 3450

OSK-W-20-2139-W8
115 -52 1125 452980 5435549 420 3450

OSK-W-20-2139-W10
115 -52 1212 452980 5435549 420 3450

OSK-W-20-2170-W6
128 -59 1407 453425 5435657 413 3900

OSK-W-20-2197-W2
121 -48 1064 453087 5435526 417 3550

OSK-W-20-2217-W2
134 -48 893 452944 5435565 418 3425

OSK-W-20-2217-W3
134 -48 1128 452944 5435565 418 3425

OSK-W-20-2249
132 -56 759 452775 5435192 411 3100

OSK-W-20-2250
132 -57 1064 453129 5435505 419 3575

OSK-W-20-2250-W1
132 -57 1060 453129 5435505 419 3575

OSK-W-20-2250-W2
132 -57 1134 453129 5435505 419 3575

OSK-W-20-2250-W3
132 -57 1170 453129 5435505 419 3575

OSK-W-20-2250-W4
132 -57 1005 453129 5435505 419 3575

OSK-W-20-2252-W2
129 -54 1194 453241 5435694 415 3750

OSK-W-20-2252-W3
129 -53 1062 453241 5435694 415 3750

OSK-W-20-2253
128 -54 924 452831 5435326 413 3225

OSK-W-20-2256
125 -51 1179 453160 5435686 414 3675

OSK-W-20-2256-W2
125 -51 957 453160 5435686 414 3675

OSK-W-20-2260-W2
127 -48 1191 453201 5435667 413 3700

OSK-W-20-2263
128 -49 1029 452926 5435187 413 3225

OSK-W-20-2266
128 -55 1050 453067 5435478 418 3500

OSK-W-20-2266-W1
128 -55 1116 453067 5435478 418 3500

OSK-W-20-2266-W2
128 -55 1131 453067 5435478 418 3500

OSK-W-20-2267
135 -52 66 452972 5435210 416 3275

OSK-W-20-2268-W1
127 -55 1073 453148 5435488 418 3575

OSK-W-20-2268-W2
127 -55 1038 453148 5435488 418 3575

OSK-W-20-2269
133 -50 933 452972 5435210 416 3275

OSK-W-20-2271
120 -53 1247 453462 5435683 410 3950

OSK-W-20-2272
149 -45 1004 452967 5435265 412 3300

OSK-W-20-2273
129 -51 1059 453067 5435478 417 3500

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-20-2282
148 -56 588 452875 5435181 409 3175

OSK-W-20-2283
135 -50 1151 452997 5435607 425 3500

OSK-W-20-2288
146 -51 749 452875 5435181 409 3175

OSK-W-20-2292
125 -54 1059 453037 5435563 420 3525

OSK-W-20-2295
132 -51 987 452938 5435472 415 3375

OSK-W-20-2295-W1
132 -51 960 452938 5435472 415 3375

OSK-W-20-2298
137 -50 596 452847 5435059 407 3100

OSK-W-20-2305
124 -55 911 453026 5435408 413 3425

OSK-W-20-2306
152 -55 531 452872 5435155 407 3175

OSK-W-20-2307
124 -54 878 453397 5435557 413 3825

OSK-W-20-2310
333 -51 144 451970 5434835 407 2225

OSK-W-20-2312
334 -51 192 451964 5434816 408 2225

OSK-W-20-2324
334 -51 167 451944 5434811 406 2200

WST-20-0135
187 -58 444 453226 5435125 134 3475

WST-20-0318
148 -52 502 453228 5435127 134 3475

WST-20-0339
146 -18 295 453410 5435229 114 3675

WST-20-0341A
163 -42 493 453228 5435126 134 3475

WST-20-0345
136 -21 401 452282 5434975 263 2575

WST-20-0400
167 16 172 453493 5435287 118 3775

WST-20-0411
156 38 171 453450 5435264 118 3725

WST-20-0412
164 24 165 453450 5435264 117 3725

WST-20-0417
138 -50 759 453228 5435126 134 3475

WST-20-0423
134 -18 142 453359 5435209 154 3625

WST-20-0459
153 -47 579 453227 5435126 135 3475

WST-20-0462
152 -53 680 453227 5435125 134 3475

WST-20-0470
158 9 184 453493 5435287 118 3775


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.


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.


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.


Bobcat


Mineralization most commonly occurs in gold-bearing quartz-pyrite veins controlled by northeast trending faults and shears and to a lesser extent in minor crustiform quartz-tourmaline-ankerite-pyrite veins and pyrite replacement zones and stockwork. Mineralization is hosted in sheared mafic volcanics, rhyolites near faults, or at the contact with felsic porphyritic intrusions.


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, 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 i


n


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 (1,20


6


,000 ounces) in the indicated mineral resource category and 14,532,000 tonnes at 8.40 g/t Au (3,93


8


,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


.


V


ein-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


intrusi


ons.


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


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; 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 a


n


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


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