MONTREAL, QUEBEC--(Marketwired - Jan 23, 2017) - Osisko Mining Inc. (OSK.TO)("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. Nine drills are currently active directly on the Windfall deposit, with additional drills planned to be added by month end. Including areas outside the main deposit, a total of 12 drills are currently active. New analytical results from five drill holes focussed on expansion and infill drilling in the Caribou and Underdog corridors are reported in this release, with significant assay results presented in the table below.

Significant new results include: 12.7 g/t Au over 5.4 metres in OSK-W-16-749 and 10.3 g/t Au over 3.0 metres in OSK-W-16-743-W2; 11.0 g/t Au over 2.4 metres and 8.13 g/t Au over 2.6 metres in OSK-W-16-743-W1. Maps and sections showing hole locations and full analytical results are available at www.osiskomining.com.

Notes:

1. True Widths are estimated at 65 - 80% of the reported core length interval. See "Quality Control" below.
2. Definitions: HW = hanging wall; FW = footwall

Caribou Corridor

Four of the drill holes intersected the CS1 Zone of the Caribou Corridor, expanding it to 360 metres by 200 metres. The CS1 Zone remains open down plunge.

OSK-W-16-749 returned 12.7 g/t Au over 5.4 metres hosted in a silicified porphyry dyke containing 2% to 35% pyrite stringers and disseminations. This intercept is located 120 metres to the southwest of previously released OSK-W-16-706 which returned 8.65 g/t Au over 3.0 metres.

OSK-W-16-743-W2 intersected 10.3 g/t Au over 3.0 metres in a bleached andesite containing 5% - 20% pyrite stringers and disseminations, expanding the CS1 Zone 120 metres down-dip.

OSK-W-16-754 assayed 7.15 g/t Au over 2.1 metres in the strongly silicified and sericitized contact between a porphyry dike and andesite containing 5-20% pyrite stringers with minor visible gold. This hole expands the CS1 Zone 60 metres down-plunge from previously reported OBM-15-564 which returned 5.59 g/t Au over 7.4 metres. The hole also intersected 4.94 g/t Au over 3.0 metres in the FW0 Zone and 3.66 g/t Au over 2.6 metres in the FW0 Footwall Zone, both of which contain mineralization similar in style to that above the Red Dog.

OSK-W-16-756 intersected 3.29g/t Au over 2.6 meters and extended the CS1 Zone 60 metres northeast of previously reported OBM-15-564 (5.59 g/t Au over 7.4 meters) and 95 metres above previously reported OSK-W-16-754 (7.15 g/t Au over 2.1 metres). Mineralization comprises 15% pyrite stringers at the contact between a porphyry dike and strongly sericitized andesite.

Underdog Corridor

OSK-W-16-743-W1 targeted several parallel zones of the Underdog Corridor and intersected 5.77 g/t Au over 5.2 meters, extending the FW0 Zone by 100 metres southwest of previously reported OBM-15-560 (12.5 g/t Au over 2.0 meters). Mineralization consists of 10% to 30% pyrite stringers in a strongly silicified fragmental porphyry dike. The FW0 Zone has been intersected by eight drill holes to date and now defines an area 210 metres by 290 metres.

The hole also intersected the FW2 Zone assaying 8.13 g/t Au over 2.6 metres and extends the zone by 130 metres west of previously reported OSK-W-16-743 (47.0 g/t Au over 2.6 metres; 303.1 g/t Au over 2.6 metres uncut). Gold mineralization is hosted in a silicified porphyry dike containing semi-massive pyrite. The FW2 hanging wall returned 6.77 g/t Au over 2.1 metres in a silicified porphyry dike containing 2-5% pyrite and the FW3 Zone returned 6.29 g/t Au over 2.0 metres at the contact between felsic volcanics with 2-3% pyrite stringers and disseminations.

Qualified Person

The scientific and technical content of this news 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 and Reporting Protocols

True widths of the new exploration intercepts below Red Dog 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. True widths of intercepts in the zones above the Red Dog are estimated at 65-80% of the reported core length intervals. Assays 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.