Osisko Announces New Results from Ongoing Drill Program at Windfall Lake Gold Project in Quebec

Osisko Mining Inc. (TSX:OSK), "Osisko" or the "Corporation") is pleased to announce further new results from the ongoing 150,000 metre drill program at its 100% owned Windfall Lake gold project located in the Urban Township, Québec. The current drill program combines definition drilling above the Red Dog intrusion ("Red Dog"), expansion drilling above and below Red Dog and exploration drilling on the greater deposit and overall property area. Seven drills are currently on site, and an additional four drills are planned to be added to the program in the coming weeks. A total of seven new holes are reported in this release.

Significant new results include: 25.1 g/t Au over 2.0 metres and 15.5 g/t Au over 2.9 metres in DDH OSK-W-16-704-W1; and 13.0 g/t Au over 2.0 metres in DDH OSK-W-16-311-W2. The new results continue to demonstrate the continuity and high potential for significant new gold mineralization below Red Dog. Details of the new results are outlined in the table below.

Notes:

1. For complete drilling results please see www.osiskomining.com

2. True Widths are estimated at 65 - 80% of the reported core length interval. See "Quality Control" below.

Drill Hole Collar Coordinates and Information

DDH OSK-W-16-704 ext was extended to test the FW3 Zone immediately below Red Dog. The FW3 Zone was intersected with 3-10% pyrite stringers and disseminations in a moderately sericitized volcanic rock unit, containing only weak gold mineralization.

DDH OSK-W-16-704-W1 intersected the FW3 Zone returning 15.5 g/t Au over 2.9 meters in a porphyry dyke containing 15-20% pyrite stringers and disseminations. This intercept is located 105 metres above DDH EAG-12-421 which returned 4.04 g/t Au over 2.2 metres (previously reported). Another zone was intersected 20 meters to the NW of the FW3 Zone which returned 6.1 g/t Au over 6.3 meters. Gold mineralization is hosted in a sericitized and silicified porphyry dyke containing 3-5% pyrite stringers and disseminations with traces of chalcopyrite. The FW4 zone returned 25.1 g/t Au over 2.0 meters in a sparsely drilled sector in the footwall of FW3 Zone. Gold mineralization is hosted in a strongly silicified and sericitized porphyry dyke containing 3-10% pyrite stringers and disseminations with traces of chalcopyrite and specks of visible gold.

DDH OSK-W-16-706-W2 tested the Underdog FW1 and FW3 Zones. Gold mineralization was intersected in the hanging wall of the FW3 Zone, returning 3.06 g/t Au over 4.5 metres in a silicified porphyry dyke containing 1-5% pyrite stringers and disseminations. The FW3 Zone returned 4.95 g/t Au over 3.5 metres at the contact of a silicified porphyry dyke containing 1-2% pyrite stringers and disseminations with several specks of visible gold. A new zone was also intersected in the footwall of the FW3, returning 7.33 g/t Au over 2.0 metres near a strongly silicified porphyry dyke contact containing 3-8% pyrite stringers and disseminations.

DDH OSK-W-16-311-W1 and DDH OSK-W-16-311-W2 expanded gold mineralization in a new zone for 135 metres along strike with intervals returning 9.40 g/t Au over 3.0 metres and 13.0 g/t Au over 2.0 metres respectively. These intervals correlate with previously a reported intercept in DDH OBM-16-655 of 10.2 g/t Au over 4.5 metres and confirm the potential for new gold zones below Red Dog. The two intervals are located in a silicified and sericitized porphyry dyke containing 2-5% pyrite stringers and disseminations with specks of visible gold. The FW3 Zone returned 6.55 g/t Au over 2.4 metres in a strongly silicified porphyry dyke containing up to 20% pyrite stringers and disseminations. An interval was also intersected 20 metres to the NW of FW3 which returned 7.87 g/t Au over 2.7 metres in a strongly sericitized porphyry dyke containing 1-2% pyrite.

DDH OSK-W-16-726-W1 tested the FW3 Zone in the western part of the deposit and 70 metres down-plunge from previously reported DDH NOT-07-110 which returned 12.3 g/t Au over 5.0 metres. The hole intersected the weakly altered favourable porphyry dykes and did not return any significant results.

DDH OSK-W-16-726-W2 was abandoned before intersecting the FW3 Zone and no significant results were reported.
Full analytical results from the seven new drill holes are available at www.osiskomining.com.

Qualified Person

The scientific and technical content of this press release has been reviewed, prepared and approved by Mr. Jean-Philippe Desrochers, Ph.D., P.Geo. Senior 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

True widths of the new exploration intercepts reported in this press release have yet to be determined. Additional drilling is planned for the immediate area which will enable the true width determination. Assays are uncut except where indicated. All NQ core assays reported were obtained by either 1 kg 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 kg 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 analysed 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 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 assays.