Osisko Windfall Drilling Returns More High-Grade

Including 512 g/t Au Over 2.4 Metres, 212 g/t Au Over 2.4 Metres in Lynx

TORONTO, Sept. 07, 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 142 intercepts in 32 drill holes (16 from surface, 16 from underground) and 24 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 continues to deliver high-grade intercepts, especially in the Lynx and Underdog zones. Infill drilling has consistently delivered throughout our drill campaign, which is winding down this fall as we approach the completion of our drilling for the feasibility study next year. The great potential for growth at Windfall continues to be demonstrated by new high-grade intercepts located outside the February 2021 resource blocks. Windfall has shown its ability to deliver high-grade results time and time again, it’s a strong and consistent mineralized system. As we move to completion of the infill program at Windfall, we are also beginning to move additional drills to the new Golden Bear discovery area and expect to have an update on our progress there in the coming weeks.”

Selected high-grade intercepts include:

512 g/t Au over 2.4 metres

in WST-21-0833;

212 g/t Au over 2.4 metres

in WST-21-0842;

86.8 g/t Au over 3.4 metres

in OSK-W-21-2287-W4;

141 g/t Au over 2.0 metres

and

29.0 g/t Au over 5.5 metres

in OSK-W-21-2503-W4;

108 g/t Au over 2.3 metres

in OSK-W-21-2531-W1;

42.1 g/t Au over 4.8 metres

in OSK-W-21-2470;

17.3 g/t Au over 11.4 metres

in OSK-W-21-2537-W1;

83.0 g/t Au over 2.0 metres

in OSK-W-21-2548-W2, and

57.6 g/t Au over 2.1 metres

in WST-21-0854A. 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-20-2292-W6

862.7

864.8

2.1

5.68


TLX_3184

Triple Lynx

OSK-W-20-2400

1051.7

1054.3

2.6

4.57


UDD_4903

Underdog


1060.9

1063.0

2.1

17.7


UDD_4904


Underdog


including
1060.9 1061.9 1.0 37.0

OSK-W-21-1432-W5

932.8

935.0

2.2

3.76


LX4_3437

Lynx 4


943.0

946.1

3.1

12.5


LX4_3437

Lynx 4

OSK-W-21-1827-W5

1101.7

1104.7

3.0

37.4


UDD_4513


Underdog


including
1102.7 1103.7 1.0 85.9


1135.0

1137.0

2.0

5.12


UDD_4514

Underdog

OSK-W-21-1827-W6

503.7

505.7

2.0

8.94

CA2_2231

Caribou


507.5

510.4

2.9

15.7

CA2_2231


Caribou


including
507.5 508.4 0.9 42.2


514.1

516.3

2.2

6.59


CA2_2231


Caribou


including
514.1 514.6 0.5 27.2


523.8

526.1

2.3

5.53


CA2_2241


Caribou


including
524.8 525.3 0.5 19.6

OSK-W-21-1882-W5

903.3

905.6

2.3

16.4


UDD_4515


Underdog


including
903.3 904.2 0.9 39.6


957.0

959.0

2.0

4.30


UDD_4501

Underdog


1020.5

1023.0

2.5

19.2


UDD_4910


Underdog


including
1020.5 1021.4 0.9 52.4

OSK-W-21-1949-W7

746.4

748.5

2.1

27.0

14.5

LXM_3345


Lynx


including
746.4 746.7 0.3 187 100


1082.0

1084.0

2.0

3.51


LX4_3430

Lynx 4

OSK-W-21-2067-W7

1089.6

1093.0

3.4

7.02


TLX_3162

Triple Lynx

OSK-W-21-2287-W4

1285.2

1288.6

3.4

86.8

42.1

LX4_3449


Lynx 4


including
1285.9 1286.2 0.3 448 100

and
1286.2 1286.5 0.3 215 100

OSK-W-21-2287-W5

1252.9

1254.9

2.0

8.28


LX4_3449

Lynx 4


1308.0

1310.7

2.7

23.2


LX4_3445

Lynx 4

OSK-W-21-2470

965.0

969.8

4.8

42.1

34.9

TLX_3163


Triple Lynx


including
969.2 969.8 0.6 158 100

OSK-W-21-2479-W6

906.0

908.0

2.0

6.29


UDD_4502


Underdog


including
907.0 907.5 0.5 24.3

OSK-W-21-2479-W7

793.6

796.1

2.5

5.90


UDD_4107

Underdog

OSK-W-21-2479-W8

920.7

923.0

2.3

9.74


UDD_4502


Underdog


including
920.7 921.1 0.4 49.5


959.8

961.8

2.0

8.06


UDD_4910

Underdog

OSK-W-21-2503-W4

967.1

972.6

5.5

29.0

23.3

TLX_3163


Triple Lynx


including
967.9 968.3 0.4 179 100


990.0

992.0

2.0

17.8


TLX_3164


Triple Lynx


including
991.3 992.0 0.7 39.7


1009.0

1011.0

2.0

141

20.1

TLX_3164


Triple Lynx


including
1009.7 1010.1 0.4 704 100

OSK-W-21-2522-W4

656.0

658.8

2.8

12.3


LXM_3304

Lynx

OSK-W-21-2531-W1

789.0

791.0

2.0

5.48


UDD_4111


Underdog


including
790.0 790.7 0.7 11.3


823.0

825.0

2.0

5.91


UDD_4110

Underdog


887.6

891.5

3.9

22.0

21.1

UDD_4101


Underdog


including
887.6 888.0 0.4 109 100


896.0

898.0

2.0

12.0


UDD_4100


Underdog


including
897.5 898.0 0.5 31.6


901.0

903.0

2.0

10.7


UDD_4100


Underdog


including
901.0 902.0 1.0 20.5


905.7

908.0

2.3

108

43.7

UDD_4100


Underdog


including
905.7 906.7 1.0 247 100


1070.4

1072.8

2.4

8.05


UDD_4501


Underdog


including
1072.1 1072.8 0.7 27.3


1181.0

1183.9

2.9

9.72


UDD_4512


Underdog


including
1182.8 1183.1 0.3 53.0

OSK-W-21-2532-W1

567.9

570.3

2.4

24.2


CA2_2206


Caribou


including
569.2 570.3 1.1 51.6


758.0

760.0

2.0

3.96


UDD_4121

Underdog


783.0

785.0

2.0

5.54


UDD_4101

Underdog


800.3

804.0

3.7

20.2


UDD_4101


Underdog


including
802.3 803.1 0.8 69.7


807.9

810.0

2.1

22.5


UDD_4100

Underdog


815.0

817.0

2.0

6.57


UDD_4120


Underdog


including
816.2 816.7 0.5 25.6


971.0

973.0

2.0

8.53


UDD_4511


Underdog


including
971.0 971.5 0.5 30.0

OSK-W-21-2532-W2

828.0

830.1

2.1

40.8

34.2

UDD_4100


Underdog


including
829.1 829.6 0.5 128 100


887.4

889.4

2.0

9.66


UDD_4106

Underdog


953.0

955.0

2.0

6.26


UDD_4107

Underdog


983.6

985.9

2.3

16.4


UDD_4511


Underdog


including
983.6 984.0 0.4 40.2

and
985.5 985.9 0.4 53.1


1015.2

1017.5

2.3

4.76


UDD_4501

Underdog

OSK-W-21-2537

909.4

914.4

5.0

6.90


TLX_3171


Triple Lynx


including
912.4 913.4 1.0 14.9


916.9

921.2

4.3

4.47


TLX_3171

Triple Lynx


925.0

928.8

3.8

3.92


TLX_3171

Triple Lynx


935.0

943.0

8.0

11.4


TLX_3161


Triple Lynx


including
939.4 940.4 1.0 42.6


1018.0

1020.0

2.0

10.3


TLX_3164


Triple Lynx


including
1019.0 1019.5 0.5 30.6

OSK-W-21-2537-W1

559.0

561.0

2.0

5.91


TLX_3196

Triple Lynx


586.8

589.0

2.2

11.2


TLX_3178


Triple Lynx


including
586.8 587.7 0.9 27.2


901.0

903.0

2.0

4.91


TLX_3171

Triple Lynx


912.6

924.0

11.4

17.3


TLX_3171


Triple Lynx


including
912.6 913.7 1.1 52.0

and
918.8 919.4 0.6 46.5

OSK-W-21-2544

987.6

989.6

2.0

3.72


TLX_3195


Triple Lynx


including
987.6 987.9 0.3 15.3

OSK-W-21-2548

721.0

723.0

2.0

22.5


CA2_2220


Caribou


including
721.0 721.6 0.6 73.8

OSK-W-21-2548-W1

758.0

760.0

2.0

3.86

CA2_2219


Caribou


including
759.0 760.0 1.0 7.67

OSK-W-21-2548-W2

757.0

759.0

2.0

83.0

53.0

CA2_2219


Caribou


including
757.0 758.0 1.0 160 100


771.0

773.0

2.0

8.27


Caribou

Caribou

OSK-W-21-2551-W1

837.1

840.1

3.0

10.8


LX4_3414

Lynx 4

OSK-W-21-2552

600.0

602.2

2.2

3.60


UDD_4914


Underdog


including
600.5 600.8 0.3 17.9


615.8

617.9

2.1

22.0


UDD_4103


Underdog


including
616.6 617.5 0.9 51.0

OSK-W-21-2555

635.0

637.1

2.1

7.43


CA2_2223

Caribou

OSK-W-21-2556

139.0

141.0

2.0

12.0


F51_6008

F-51

OSK-W-21-2560

603.9

609.4

5.5

19.3

15.0

UDD_4914


Underdog


including
609.0 609.4 0.4 159 100

OSK-W-21-2561

555.0

557.0

2.0

3.88


TLX_3178

Triple Lynx


659.9

662.9

3.0

16.0


TLX_3171

Triple Lynx

OSK-W-21-2562

656.2

658.2

2.0

5.48


CA2_2208

Caribou


683.0

692.0

9.0

11.6


CA2_2217


Caribou


including
685.2 685.6 0.4 97.1

and
688.5 689.0 0.5 42.3

OSK-W-21-2566

134.0

136.0

2.0

4.81


F51_6008

F-51

OSK-W-21-2567

137.7

139.8

2.1

22.1


F51_6008


F-51


including
138.1 139.0 0.9 43.3

WST-21-0718

79.5

82.1

2.6

3.95


LXM_3304


Lynx


including
81.7 82.1 0.4 10.0

WST-21-0772

347.0

349.0

2.0

4.62


TLX_3166


Triple Lynx


including
348.4 349.0 0.6 14.6

WST-21-0797A

599.2

601.4

2.2

6.53


LX4_3429


Lynx 4


including
600.5 600.9 0.4 25.3

WST-21-0833

278.0

280.4

2.4

512

45.3

LHW_3201


Lynx HW


including
278.0 279.0 1.0 1220 100

WST-21-0835

281.0

283.0

2.0

4.67


LHW_3221

Lynx HW


328.9

331.0

2.1

25.7


LHW_3215


Lynx HW


including
329.5 330.4 0.9 56.6

WST-21-0840

713.0

715.0

2.0

3.72


LX4_3412

Lynx 4

WST-21-0842

250.6

253.0

2.4

212

42.1

TLX_3161


Triple Lynx


including
251.1 251.6 0.5 917 100

WST-21-0850

83.0

85.4

2.4

6.47


LXM_3339


Lynx


including
85.0 85.4 0.4 16.7


267.8

270.1

2.3

8.14


LSW_3500


Lynx SW


including
268.3 268.9 0.6 29.6


326.8

329.3

2.5

10.2


TLX_3166


Triple Lynx


including
326.8 327.3 0.5 49.0

WST-21-0851A

168.6

170.7

2.1

13.4


LXM_3304


Lynx


including
169.1 169.4 0.3 87.5


480.0

482.4

2.4

6.06


LX4_3430


Lynx 4


including
481.8 482.4 0.6 24.0


518.6

521.0

2.4

5.93


LX4_3440


Lynx 4


including
518.6 519.4 0.8 16.4


528.0

530.0

2.0

5.84


LX4_3434


Lynx 4


including
528.5 529.0 0.5 20.0


590.0

592.2

2.2

4.93


LX4_3439


Lynx 4


including
590.0 590.6 0.6 16.1

WST-21-0852A

127.5

129.6

2.1

7.07


LXM_3334


Lynx


including
128.8 129.3 0.5 26.1


420.1

422.3

2.2

3.98


LX4_3452


Lynx 4


including
420.6 421.3 0.7 11.3


487.2

489.2

2.0

23.2


LX4_3450


Lynx 4


including
487.2 487.7 0.5 90.7


648.0

650.0

2.0

11.1


LX4_3438


Lynx 4


including
649.3 649.6 0.3 34.7


669.7

672.2

2.5

3.75


LX4_3415


Lynx 4


including
669.7 670.2 0.5 10.4

WST-21-0853A

289.3

291.3

2.0

6.49


TLX_3161


Triple Lynx


including
290.6 291.3 0.7 16.2


347.6

349.7

2.1

6.72


TLX_3163


Triple Lynx


including
348.4 349.1 0.7 19.0

WST-21-0854A

185.9

188.0

2.1

57.6


TLX_3161


Triple Lynx


including
187.0 188.0 1.0 93.1


300.0

302.1

2.1

4.59


TLX_3182


Triple Lynx


including
300.8 301.5 0.7 12.8


353.7

356.0

2.3

3.91


TLX_3188


Triple Lynx


including
355.3 355.6 0.3 22.0


654.0

656.0

2.0

10.6


LX4_3448


Lynx 4


including
654.8 655.2 0.4 48.1

WST-21-0869

357.0

359.0

2.0

12.4


TLX_3167

Triple Lynx


510.6

512.9

2.3

6.91


LX4_3450

Lynx 4

WST-21-0870

288.6

290.6

2.0

13.8


LSW


Lynx SW


including
289.8 290.2 0.4 51.0


299.0

301.0

2.0

18.0


LSW


Lynx SW


including
300.1 301.0 0.9 38.9


329.9

335.0

5.1

19.3


LSW_3556


Lynx SW


including
332.4 332.7 0.3 84.6

WST-21-0871

324.6

327.0

2.4

4.45


TLX_3131


Triple Lynx


including
324.6 324.9 0.3 35.0

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, LHW = Lynx Hanging Wall, LSW = Lynx SouthWest, TLX = Triple Lynx and UDD = Underdog, CA2 = Caribou.



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-21-1432-W5

895.5

898.0

2.5

5.81


LX4


Lynx 4


including
896.2 897.0 0.8 17.6

OSK-W-21-1827-W5

1087.0

1089.5

2.5

14.7


UDD


Underdog


including
1087.0 1088.0 1.0 28.8

OSK-W-21-2287-W4

1304.8

1307.0

2.2

4.26


LX4


Lynx 4


including
1305.4 1305.7 0.3 19.0


1373.0

1375.0

2.0

4.84


LX4

Lynx 4

OSK-W-21-2478-W5

555.0

557.0

2.0

4.90


Triple Lynx

Triple Lynx

OSK-W-21-2479-W7

759.0

761.0

2.0

3.88


UDD

Underdog

OSK-W-21-2513

256.2

259.0

2.8

3.95


F51

F51

OSK-W-21-2522-W4

697.0

700.0

3.0

4.68


Lynx

Lynx

OSK-W-21-2532-W1

826.6

829.1

2.5

11.6


Underdog


Underdog


including
827.6 828.2 0.6 47.4

OSK-W-21-2537

971.0

975.0

4.0

4.33


Triple Lynx

Triple Lynx

OSK-W-21-2540-W1

1132.1

1134.4

2.3

4.47


Triple Lynx

Triple Lynx


1141.6

1143.7

2.1

4.27


Triple Lynx


Triple Lynx


including
1143.4 1143.7 0.3 17.7

OSK-W-21-2546-W1

579.0

581.4

2.4

4.06


Caribou extension


Caribou


including
580.0 580.4 0.4 23.0


631.9

635.8

3.9

4.27


Caribou extension


Caribou


including
631.9 632.2 0.3 14.6

and
635.1 635.8 0.7 13.2


819.7

822.0

2.3

4.78


Caribou extension


Caribou


including
819.7 820.5 0.8 11.0

OSK-W-21-2548

731.0

733.2

2.2

5.08


Caribou

Caribou

OSK-W-21-2548-W1

790.8

792.8

2.0

5.99

Caribou


Caribou


including
792.4 792.8 0.4 27.3

OSK-W-21-2549

461.0

463.0

2.0

13.4


Caribou


Caribou


including
461.5 461.9 0.4 55.5


641.5

645.0

3.5

11.5


Caribou


Caribou


including
642.6 643.2 0.6 37.6


705.4

708.0

2.6

14.7


Caribou


Caribou


including
705.4 706.1 0.7 32.2

OSK-W-21-2555

610.0

612.3

2.3

3.70


Caribou


Caribou


including
611.9 612.3 0.4 12.7

OSK-W-21-2559

656.0

658.0

2.0

5.86


Caribou

Caribou

OSK-W-21-2562

649.9

654.8

4.9

22.4


Caribou


Caribou


including
651.0 651.6 0.6 48.2

WST-21-0772

242.0

244.0

2.0

44.7


LSW


Lynx SW


including
242.7 243.6 0.9 99.1


249.0

251.0

2.0

3.63


LSW


Lynx SW


including
249.5 249.8 0.3 23.3

WST-21-0831

160.8

163.0

2.2

4.45


LSW


Lynx SW


including
160.8 161.4 0.6 15.8


403.4

405.4

2.0

5.45


LSW


Lynx SW


including
403.8 404.4 0.6 17.2

WST-21-0840

343.0

345.9

2.9

5.91


TLX

Triple Lynx


374.5

377.0

2.5

11.4


TLX

Triple Lynx

WST-21-0850

417.7

420.0

2.3

42.5


LSW


Lynx SW


including
417.7 418.5 0.8 95.6

WST-21-0852A

29.6

32.0

2.4

17.5


Lynx


Lynx


including
29.6 30.2 0.6 65.8


146.0

148.0

2.0

4.19


Lynx


Lynx


including
146.3 146.7 0.4 20.4

WST-21-0854A

546.0

548.1

2.1

4.64


LX4

Lynx 4

WST-21-0871

570.9

573.0

2.1

9.34


LX4

Lynx 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, LSW = Lynx SouthWest, TLX = Triple Lynx, UDD = Underdog.



Drill hole location


Hole Number

Azimuth (°)

Dip (°)

Length (m)

UTM E

UTM N

Elevation

Section

OSK-W-20-2292-W6
125 -54 1110 453035 5435561 420 3500

OSK-W-20-2400
336 -53 1230 452878 5434419 401 2825

OSK-W-21-1432-W5
132 -55 1041 453811 5435779 400 4300

OSK-W-21-1827-W5
331 -58 1203 452506 5434390 403 2475

OSK-W-21-1827-W6
331 -58 1281 452506 5434390 403 2475

OSK-W-21-1882-W5
328 -58 1071 452469 5434405 400 2450

OSK-W-21-1949-W7
105 -57 1312 453440 5435479 401 3825

OSK-W-21-2067-W7
123 -53 1166 453241 5435697 416 3750

OSK-W-21-2287-W4
116 -53 1437 453607 5435714 404 4075

OSK-W-21-2287-W5
116 -53 1380 453607 5435714 404 4075

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

OSK-W-21-2478-W5
128 -54 1166 452997 5435607 425 3500

OSK-W-21-2479-W6
344 -55 1014 452315 5434419 399 2325

OSK-W-21-2479-W7
344 -55 999 452315 5434419 399 2325

OSK-W-21-2479-W8
344 -55 1026 452315 5434419 399 2325

OSK-W-21-2503-W4
126 -58 1191 453333 5435641 413 3800

OSK-W-21-2513
147 -45 281 453518 5436030 405 4150

OSK-W-21-2522-W4
128 -54 1208 453451 5435594 411 3900

OSK-W-21-2531-W1
344 -62 1215 452566 5434415 403 2550

OSK-W-21-2532-W1
341 -60 1035 452480 5434428 401 2475

OSK-W-21-2532-W2
341 -60 1145 452480 5434428 401 2475

OSK-W-21-2537
114 -54 1243 452981 5435549 420 3450

OSK-W-21-2537-W1
114 -54 1020 452981 5435549 420 3450

OSK-W-21-2540-W1
117 -60 1200 453465 5435640 410 3925

OSK-W-21-2544
128 -50 1161 452960 5435539 419 3425

OSK-W-21-2546-W1
140 -58 843 452768 5435312 406 3150

OSK-W-21-2548
331 -57 774 452829 5434550 398 2850

OSK-W-21-2548-W1
331 -57 837 452829 5434550 398 2850

OSK-W-21-2548-W2
331 -57 801 452829 5434550 398 2850

OSK-W-21-2549
332 -58 723 452703 5434455 401 2675

OSK-W-21-2551-W1
120 -55 978 453622 5435635 405 4050

OSK-W-21-2552
335 -52 684 452404 5434674 400 2525

OSK-W-21-2555
329 -59 741 452728 5434472 401 2700

OSK-W-21-2556
124 -50 198 453426 5435858 405 4000

OSK-W-21-2559
327 -51 825 452829 5434550 398 2850

OSK-W-21-2560
333 -53 684 452404 5434674 400 2525

OSK-W-21-2561
142 -51 801 452886 5435484 409 3350

OSK-W-21-2562
331 -56 753 452733 5434488 401 2725

OSK-W-21-2566
178 -58 189 453426 5435858 405 4000

OSK-W-21-2567
146 -60 186 453426 5435858 405 4000

WST-21-0718
162 0 100 453359 5435194 83 3625

WST-21-0772
148 -68 411 453104 5435065 231 3325

WST-21-0797A
138 -46 751 453321 5435235 54 3600

WST-21-0831
157 -63 526 452954 5435003 253 3175

WST-21-0833
122 -16 334 453463 5435327 32 3775

WST-21-0835
122 -27 385 453462 5435327 32 3775

WST-21-0840
143 -48 778 453258 5435209 96 3525

WST-21-0842
156 -69 445 453506 5435327 -7 3800

WST-21-0850
151 -64 532 453105 5435065 231 3325

WST-21-0851A
123 -40 618 453507 5435332 -48 3800

WST-21-0852A
141 -43 709 453321 5435236 54 3600

WST-21-0853A
150 -72 376 453505 5435328 -5 3800

WST-21-0854A
134 -41 724 453374 5435296 -26 3675

WST-21-0869
142 -47 622 453258 5435210 96 3525

WST-21-0870
134 -56 360 453106 5435066 231 3325

WST-21-0871
140 -50 582 453321 5435236 54 3600


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.


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 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



Primary Logo