OSK-W-17-972 intersected 5.23 g/t Au over 2.0 metres. The mineralization consists of 2% pyrite and 30% quartz-tourmaline veins within a gabbro.

OSK-W-17-981 returned 6.21 g/t Au over 2.1 metres in Lynx hanging wall and 5.23 g/t Au over 2.0 metres in Lynx 4. In the Lynx hanging wall the mineralization is composed of 3% disseminated pyrite and traces of pyrite stringers within a strongly sericitized rhyolite. Lynx 4 is composed of up to 5% stringers within the gabbro.

OSK-W-17-986 intersected 6.74 g/t Au over 2.0 metres in Lynx 2. Mineralization is composed of 1% pyrite fragments and traces of disseminated pyrite in a silicified fragmental felsic intrusion.

OSK-W-17-987 intersected 4.97 g/t Au over 2.3 metres in the Lynx hanging wall. Mineralization is composed of traces of disseminated pyrite with local pervasive silica flooding and carbonate veins hosted in a sericitized and strongly chloritized gabbro.

OSK-W-17-991 returned 5.11 g/t Au over 2.0 metres in Lynx 1. Mineralization is composed of 3% pyrite stringers at the contact between a chloritized gabbro and the fragmental felsic intrusion. The interval extends Lynx 1 120 metres north-east of OSK-W-17-929 (18.0 g/t Au over 2.0 metres previously reported October 3, 2017).

OSK-W-17-1007 intersected two intervals: 6.54 g/t Au over 2.0 metres in Lynx 1 and 10.5 g/t Au over 2.2 metres in a crustiform vein. The Lynx 1 mineralization is composed of 10% pyrite stringers in a chloritized and sericitized andesite at the contact with a fragmental felsic intrusion. The crustiform vein is within the Lynx 3 zone and includes 5% disseminated pyrite, 5% pyrite-tourmaline stringers and 1% crustiform quartz veins hosted in chloritized gabbro.

OSK-W-17-1058 intersected 8.50 g/t Au over 3.1 metres in Lynx 2. Mineralization is composed of a decimeter scale crustiform vein with local visible gold, 1% pyrite, disseminated sphalerite and tourmaline veins. The interval is hosted in a strongly silicified rhyolite.

OSK-W-17-1064 intersected Lynx 1 returning 8.92 g/t Au over 2.0 metres. Mineralization is composed of 3% disseminated pyrite and a crustiform vein within a pervasively silica flooded, and fuchsite altered gabbro.

OSK-W-17-1072 intersected 3.73 g/t Au over 2.3 metres in Lynx 4. Local visible gold occurs in a centimetre scale quartz vein. Mineralization also includes up to 4% pyrite-tourmaline stringers in a moderately sericitized rhyolite.

OSK-W-17-1072-W3 intersected 11.3 g/t Au over 2.0 metres in Lynx 4. Mineralization is composed of 8% pyrite stringers associated with interstitial carbonate veinlets hosted in chloritized and slightly sericitized rhyolite.

OSK-W-17-1073 intersected two intervals: 8.65 g/t Au over 2.0 metres and 3.61 g/t Au over 2.5 metres in the south-west extension of Lynx 4 near the main zone. The first interval is hosted in rhyolite and composed of 20% pyrite with silica flooding. The second interval is hosted in the andesite and is composed of 10% disseminated pyrite and quartz-carbonate veins. These intervals are 200 metres south-west of OSK-W-17-1109 (16.9 g/t Au over 4.0 metres previously reported October 12, 2017).

OSK-W-17-1085 intersected Lynx 1 and Lynx 2: 4.83 g/t Au over 2.2 metres and 4.45 g/t Au over 4.0 metres, respectively. Both intersects are hosted in a silica altered fragmental intrusion and composed of up to 3% disseminated pyrite, 2% pyrite clusters and 1% quartz-tourmaline veins.

OSK-W-17-1098 intersected 13.7 g/t Au over 2.4 metres in Lynx 3. Mineralization is composed of up to 3% pyrite stringers with quartz-carbonate veins hosted in a moderately silicified and sericitized fragmental felsic intrusion.

OSK-W-17-1104 intersected two intervals: 6.79 g/t Au over 2.8 metres in Lynx hanging wall and 10.3 g/t Au over 2.0 metres in Lynx 5. The first interval is hosted in a sericitized and fuchsitized gabbro and is composed of 1% disseminated pyrite and 1% pyrite stringers. The second interval is composed of 5% pyrite with silica flooding at the contact between the andesite and the rhyolite. Lynx 5 is extended 120 metres north-east of OSK-W-17-907 (25.9 g/t Au over 2.1 metres previously reported October 30, 2017).

OSK-W-17-1111 intersected 19.0 g/t Au over 6.8 metres in Lynx 2. The interval consists in a sericitized rhyolite with 10% pyrite stringers and pervasive silica flooding.

OSK-W-17-1128 intersected 36.1 g/t Au over 2.1 metres in Lynx 2. Mineralization is composed of up to 2% pyrite stringers within a strongly silicified and sercitized contact between a porphyritic felsic dike and the gabbro.

OSK-W-17-1136 returned 5.40 g/t Au over 2.0 metres in Lynx 2. Mineralization is composed of 15% pyrite with silica flooding within a strongly silicified fragmental felsic intrusion.

OSK-W-17-1143 returned two intervals: 27.9 g/t Au over 2.1 metres and 10.6 g/t Au over 2.0 metres. The first interval is composed of local visible gold and 30% pyrite stringers at the contact between the gabbro and the rhyolite. The second interval is within a sericitized fragmental felsic intrusion and composed of traces of disseminated pyrite. Both intervals are in Lynx 2.

OSK-W-17-1190 intersected with 6.03 g/t Au over 2.1 metres and 4.09 g/t Au over 6.0 metres. The first interval is composed of up to 20% disseminated pyrite with a centimeter scale smoky quartz vein, hosted in andesite. The second interval is a sericitized andesite containing up to 20% disseminated to locally semi-massive pyrite (50%). These intervals are 500 metres south-west of OSK-W-17-907 (30.2 g/t Au over 2.0 metres previously reported September 18, 2017) in the general up-plunge trend of Lynx 5, geometry of the zone remains to be determined.

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 widths determinations are estimated at 65-80% of the reported core length intervals for most of the zones. 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 ALS Laboratories in Val d'Or, Québec, Thunder Bay and Sudbury, Ontario or Vancouver, British Colombia or 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 Lake Gold Deposit

The Windfall Lake gold deposit is located between Val-d'Or and Chibougamau in the Abitibi region of Québec, Canada. The mineral resource defined by the previous operator 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 and nearby Quevillon area (over 3,300 square kilometres), 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 Quebec and Ontario. Osisko continues to be well financed with approximately $220 million in cash and investments.

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. The information in this news release about the Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada; the current 800,000 metre drill program; the significance of new results from the ongoing drill program at the Windfall Lake gold project; the significance of assay results presented in this press release; the type of drilling included in the drill program (definition drilling, expansion drilling to the NE of the main deposit and adjacent Lynx deposit, and exploration drilling on the greater deposit and Urban-Barry project area); potential mineralization; the potential to extend mineralization up and down-plunge and at depth at the Windfall Lake gold deposit; the ability to realize upon any mineralization in a manner that is economic; the ability to complete any proposed exploration activities and the results of such activities, including the continuity or extension of any mineralization; and any other information herein that is not a historical fact may be "forward-looking information". Any statement that involves discussions with respect to 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", "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 forward-looking information is based on reasonable assumptions and estimates of management of the Corporation. At the time it was made, involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Osisko to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. 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 interests in the Windfall Lake gold project; the ability of the Corporation to obtain required approvals and complete transactions on terms announced; 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.