Osisko Intersects 9.01 g/t Au Over 9.4 Metres At Windfall

(Toronto, May 19, 2017)  Osisko Mining Inc. (OSK:TSX, “Osisko” or the “Corporation”) is pleased to announce new results from the ongoing drill program at its 100% owned Windfall Lake gold project located in Urban Township, Québec.  The current 400,000 metre drill program combines definition drilling above the Red Dog intrusion (“Red Dog”), expansion drilling above and below Red Dog, expansion drilling to the NE of the main deposit, and exploration drilling on the greater deposit and Urban-Barry Project area.  Significant new analytical results from four wedge drill holes focused on infill and expansion drilling in the main Windfall deposit are reported in the table below.

Highlights from the new results include:  9.01 g/t Au over 9.4 metres in DDH OSK-W-17-807-W1; 26.6 g/t Au over 2.0 metres in DDH OSK-17-466-W2; and 14.6 g/t Au over 2.6 metres in DDH OSK-17-789-W1.  Maps showing drill hole locations and full analytical results are available at www.osiskomining.com.

Hole No.	From (m)	To (m)	Interval (m)	Au (g/t) uncut	Au (g/t) cut to 100 g/t	Zone	Corridor
OSK-W-17-789-W1	1004.1	1006.7	2.6	14.6		FW3	Underdog
including	1005.2	1006.0	0.8	34.3
OSK-W-1c7-807-W1	907.0	916.4	9.4	9.01		FW3	Underdog
including	913.3	915.7	2.4	20.7
OSK-W-17-466-W1	736.0	738.4	2.4	8.38		FW3U	Underdog
including	737.5	738.4	0.9	20.3
OSK-W-17-466-W2	721.0	723.0	2.0	26.6		FW3U	Underdog
including	721.3	722.3	1.0	51.5

Notes:  True widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control” below.

Hole Number	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Section
OSK-W-17-466-W1	330	-52	861	452484	5434643	2600
OSK-W-17-466-W2	330	-52	900	452484	5434643	2575
OSK-W-17-789-W1	333	-59	1198.5	452546	5434390	2525
OSK-W-17-807-W1	330	-65	1195.5	452311	5434424	2325

OSK-W-17-789-W1 returned 14.6 g/t Au over 2.6 metres including 34.3 g/t Au over 0.8 metres from a strongly silicified large quartz eyes felsic porphyry dikes. The mineralization includes up to 5% pyrite stringers, 1% chalcopyrite and local visible gold.  This intersection infills the FW3 Zone 45 metres south-west of previously reported EAG-12-320 (16.3 g/t Au 2.5 metres).

OSK-W-17-807-W1 is an infill hole on the FW3 Zone which returned 9.01 g/t Au over 9.4 metres including an interval returning 20.7 g/t Au over 2.4 metres.  Mineralization consists of up to 4% pyrite in stringers and disseminations within a fragmental porphyry dike.  This infill hole is an extension 45 metres to the north-east from previously reported hole EAG-11-311 (24.5 g/t Au over 7.4 metres).

OSK-W-17-466-W1 intersected 8.38 g/t Au over 2.4 metres including 20.3 g/t Au over 0.9 metres associated to the FW3 Upper Zone.  The mineralization is composed of up to 3% pyrite stringers and quartz tourmaline veins hosted in a silica altered andesite.  The hole is 25 metres down plunge of OSK-W-17-466-W2 (described below) and 25 metres north-east of previously reported hole EAG-11-269 (7.71 g/t Au over 6.9 metres).

OSK-W-17-466-W2 intersected 26.6 g/t Au over 2.0 metres including 51.5 g/t Au over 1 metre. Mineralization is composed of semi-massive pyrite (up to 40% in stringer texture) hosted in a bleached andesite at the contact of a felsic porphyry dike. This intersection extends the FW3 Upper Zone 30 metres north-east of previously reported hole EAG-11-289 (9.96 g/t Au over 5.8 metres).

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 the 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 determinations are estimated at 65 – 80% true core lengths.  Assay are uncut except where indicated, and calculated intervals are reported over a minimum length of 2 metres using a lower cutoff of 3 g/t Au. All NQ core assays reported were obtained by either 1 kilogram whole rock metallic screen/fire assay or standard 50 gram fire-assaying with AA or gravimetric finish at ALS Laboratories in Val d’Or, Québec or Sudbury, Ontario. The 1 kilogram metallic screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. All 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 and interpretation of results is performed by qualified persons employing a Quality Assurance/Quality Control program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for Quality Assurance/Quality Control purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assays.

About the Windfall Lake Gold Deposit
The Windfall Lake gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The current mineral resource comprises 2,762,000 tonnes at 8.42 g/t Au (748,000 ounces) in the indicated category and 3,512,000 tonnes at 7.62 g/t Au (860,000 ounces) in the inferred category (sourced from a technical report dated June 10, 2015 entitled “Preliminary Economic Assessment of the Windfall Lake Gold Property, Québec, Canada” with an effective date of April 28, 2015, prepared in accordance with NI 43-101). The Windfall Lake gold deposit is currently one of the highest grade resource-stage gold projects in Canada. The bulk of the mineralization occurs in the Main Zone, a southwest/northeast trending zone of stacked mineralized lenses, measuring approximately 600 metres wide and at least 1,400 metres long. The deposit is well defined from surface to a depth of 500 metres, and remains open along strike and at depth. Mineralization has been identified only 30 metres from surface in some areas and as deep as 870 metres in others, with significant potential to extend mineralization up and 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% in the high-grade Windfall Lake 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 (82,400 hectares), a 100% interest in the Marban project located in the heart of Québec’s prolific Abitibi gold mining district, and properties in the Larder Lake Mining Division in northeast Ontario, including the Jonpol and Garrcon deposits on the Garrison property, the Buffonta past producing mine and the Gold Pike mine property. The Corporation also holds interests and options in a number of additional properties in northern Ontario.  Osisko continues to be well financed with approximately $190 million in cash and investments.

For further information please contact:
John Burzynski, President and Chief Executive Officer
Telephone: (416) 363-8653

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