OSISKO MINING ANNOUNCES INCREASE TO PREVIOUSLY ANNOUNCED BOUGHT DEAL PRIVATE PLACEMENT

Upsized Offering to Include 2,647,000 Common Shares and, as initially announced, 26,176,471 Flow-Through Shares for Aggregate Gross Proceeds of $72.5 million

NOT FOR DISTRIBUTION TO U.S. NEWS WIRE SERVICES OR FOR DISSEMINATION IN THE UNITED STATES. 

(Toronto, August 16, 2018) – Osisko Mining Inc. (TSX:OSK) (“Osisko” or the “Corporation”) is pleased to announce that it has amended its agreement dated August 15, 2018 with Canaccord Genuity Corp., on behalf of a syndicate of underwriters (collectively, the “Underwriters”) in relation to its previously announced two- tranche “bought deal” private placement of 26,176,471 common shares of the Corporation that will qualify as “flow-through shares” (within the meaning of subsection 66(15) of the Income Tax Act (Canada) and, in relation to the first tranche of “flow-through shares”, section 359.1 of the Taxation Act (Québec)) for aggregate gross proceeds of approximately $68 million (the “Offering”).

The Offering has been amended to include an additional 2,647,000 common shares of the Corporation (the “Common Shares”) at a price of $1.70 per Common Share for additional gross proceeds of approximately $4.5 million. The terms of the previously announced two-tranche private placement financing of “flow-through shares” remain unchanged.

In addition, the Underwriters will have the option, exercisable in whole or in part at any time prior to the closing of the Offering, to increase the size of the Offering of the Common Shares by up to an additional 1,176,000 Common Shares at a price of $1.70 per Common Share for additional gross proceeds of approximately $2.0 million.

The Offering is expected to close on or about September 18, 2018 and is subject to certain conditions including, but not limited to, the receipt of all necessary approvals, including the approval of the Toronto Stock Exchange and the applicable securities regulatory authorities. The securities to be issued under the Offering will be subject to a hold period in Canada expiring four months and one day from the closing date of the Offering.

The securities offered have not been registered under the U.S. Securities Act of 1933, as amended, and may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirements. This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of the securities in any State in which such offer, solicitation or sale would be unlawful.

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 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 Corporation also holds interests and options in a number of additional properties in northern Québec and Ontario.

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 and projections as at the date of this news release. The information in this news release about the Offering; the use of the proceeds from the Offering; the jurisdictions in which the securities will be offered or sold; the number of securities offered or sold; the size of the Offering; the timing and ability of the Corporation to close the Offering, if at all; the timing and ability of the Corporation to satisfy the customary listing conditions of the Toronto Stock Exchange, if at all; the timing and ability of the Corporation to obtain all necessary approvals; the tax treatment of the securities issued under the Offering under the Income Tax Act (Canada) and Taxation Act (Québec); 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, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as “expects”, or “does not expect”, “is expected”, “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 Osisko, 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 Offering; volatility in the trading price of common shares of the Corporation; risks relating to the ability of the Corporation to obtain required approvals, complete definitive documentation and complete the Offering; the ability of Osisko to complete further exploration activities, including drilling; property interests; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; changes in the tax and regulatory regime; 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 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.

For further information please contact:

John Burzynski
President and Chief Executive Officer Telephone: (416) 363-8653

Osisko Mining Provides Ontario Exploration Update

(Toronto, February 13, 2018) Osisko Mining Inc. (OSK:TSX) (“Osisko” or the “Corporation”) is pleased to provide an update on the progress of exploration at its 100% owned Garrison gold project located in Garrison Township, Ontario.

Osisko has been conducting new exploration and definition drilling at Garrison for 20 months, since early 2016.  As of the end of January 2018, Osisko has completed 85,000 metres of new drilling to complement the pre-existing 108,000 metres drilled at Garrison by previous operators.  The company has re-evaluated previous drilling from the Jonpol Zone, continued resource delineation at the Garrcon Zone and substantially expanding the 903 Zone with exploration drilling in the southwest part of the property.  Dewatering and geological mapping of the Garrcon bulk sample pits was conducted during 2017.  Work is in progress on interpretation of the geological model of the Garrcon and 903 zones, including mineralization controls.

Exploration Budget for 2018:  $3M
Osisko’s 2018 exploration budget for the Garrison deposit totals approximately $3 million.  This includes resource estimation work, additional resource-oriented infill drilling, metallurgical work and exploration drilling on the Garrison property.

Garrison:  Updated Resource Estimation Planned for July 2018
Osisko’s updated resource estimate for the Garrison Project is scheduled to be released in July 2018. 

The Garrison property consists of three mineralized zones with different styles:  the Garrcon Zone is hosted by Temiskaming sediments in the footwall of the Destor Porcupine Fault Zone (PDFZ); the Jonpol Zone comprises 1.7 km of structurally controlled mineralization along the Munro Shear Zone hosted by mafic to ultramafic volcanic rocks; and the 903 Zone is hosted by syenite dykes intruding ultramafic rocks along the PDFZ.  The Jonpol and 903 zones remain open to the southwest and northwest respectively. The Garrcon, Jonpol and 903 zones will all be included in the 2018 updated resource.

Property Disposals
Through the course of 2017 Osisko vended the Catharine, DeSantis and Swayze exploration projects to other mining companies. 

President and CEO of Osisko John Burzynski commented: “Although our main focus is on the Windfall project in Québec, Osisko has continued work on the Garrison project, with the goal of updating the resource and improving our understanding of the potential of the Garrcon, Jonpol and 903 zones.  Drilling in 2017 was successful at significantly expanding the size of the 903 Zone.  Our upcoming July resource estimate will include all three zones (Garrcon, Jonpol and 903), and we will continue to evaluate the extensions of known mineralization with exploration drilling in 2018.” 

Qualified Person
The scientific and technical content of this press release has been reviewed, prepared and approved by Mr. Gernot Wober, P.Geo. VP Exploration Canada for Osisko Mining Inc, who is a “Qualified Person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

About the Garrison Project

The Garrison Project area is comprised of 214 mineral claims, 25 mining leases, and 87 patent claims encompassing approximately 8,000 hectares.  Both Garrcon and Jonpol have resource estimates that are described in a technical report prepared in accordance with NI 43-101, which was completed by a previous operator Northern Gold Mining Inc. (entitled “Technical Report on the Golden Bear Project – Garrison Property: Larder Lake Mining Division, Garrison Township, Ontario, Canada”) dated December 30, 2013, with an effective date of December 30, 2013 (the “Garrison Technical Report”). The Garrison Technical Report was prepared by A.C.A. Howe International Limited for Northern Gold Mining Inc. (a wholly-owned subsidiary of Osisko) and is available on Osiskos website at www.osiskomining.com and on SEDAR under Northern Gold Mining Inc.s issuer profile at www.sedar.com.

Resource estimates were conducted by A.C.A. Howe International Limited according to CIM standards. The Garrcon Zone estimates showed 15.1 million tonnes with an average grade of 1.07 g/t Au (521,000 oz) in measured resources; 14.1 million tonnes averaging 1.16 g/t Au (526,000 oz) in indicated resources; and 1.7 million tonnes averaging 0.72 g/t Au (39,000 oz) in inferred resources. Potential underground resources of 5.1 million tonnes averaging 3.49 g/t Au (577,000 oz) in the inferred category were also outlined. Resources were reported at a cut-off grade of 0.4 g/t Au for open pit extraction and 1.5 g/t in a bulk underground mining scenario using a gold price of US$1,250/oz.

At the Jonpol Zone, resources were estimated as 0.87 million tonnes averaging 5.34 g/t Au (150,000 oz) in the indicated category; and 1.07 million tonnes averaging 5.56 g/t Au (192,000 oz) in inferred resources. Resources were reported at a cut-off grade of 3.0 g/t Au and assume an underground extraction scenario using a gold price of US$1,250/oz.

Readers are cautioned that inferred resources have a great amount of uncertainty as to their existence and as to whether they can be mined economically. It cannot be assumed that all or any part of the inferred resources will ever be upgraded to a higher category. Mineral resources are not mineral reserves and do not have demonstrated economic viability.

Garrcon Zone

The Garrcon Zone has a shallow plunge eastward along the footwall of the Destor-Porcupine Fault Zone with the bulk of the resource in the western, more densely drilled area. The zone is exposed at surface and has potential for open pit bulk mining at an estimated overall stripping ratio of 1.8:1. There is potential for additional underground resources below the pit and along the easterly plunge of the zone, which is open for further exploration down dip and along strike.

The Garrcon shaft was sunk in 1935 and 1936 by the Consolidated Mining and Smelting Co. of Canada (“Cominco”) and the Shaft and South Zones were tested for high grade gold mineralization. Cominco drove approximately 1,430 metres of drifts and cross cuts, mining underground veins. Diamond drilling by Cominco and Lac Minerals Ltd. in the mid-to-late 1980s identified broad sections of low grade mineralization. In 2006-2007, ValGold Resources Ltd. conducted additional drilling confirming these zones. From 2009-2013 Northern Gold Mining Inc. conducted 97,000 metres of diamond drilling which delineated the current resource.

In 2014, Northern Gold Mining Inc. was granted a trial mining permit allowing the extraction of up to 150,000 tonnes. Northern Gold Mining Inc. mined 73,534 dry tonnes which was processed at the nearby Holt mill facility recovering 3,516 oz at an average head grade of 1.55 g/t and recovery of 95.9%.

Jonpol Zone

Jonpol is situated in the Munro Fault Zone, a west striking splay off the north side of the Destor-Porcupine Fault. Hosted in a shear zone tens of metres wide in altered mafic volcanic rocks, the deposit consists of four high grade gold mineralized zones (JP, JD, RP and East) over a strike length of 1.7 kilometers. Gold mineralization is hosted in quartz carbonate veins, in mafic and ultramafic host rocks, and is associated with intense albite and/or sericite alteration and pyrite mineralization.

In 1997, a 49,087 tonne bulk sample was extracted from the central part of the JP zone by Hillsborough Resources Limited with an average grade of 6.7 g/t which produced 9,476 ounces Au. From 1985-2013, over 130,000 metres of drilling was completed on the property by previous operators. Development work on the JP zone included the sinking of a 184 metre shaft as well as development of a ramp to the 150 metres level with mining on six sublevels. The Jonpol infrastructure underwent reclamation in the late 1990s and was closed out in 2001, but the existing ramp and shaft are preserved.

903 Zone

This third mineralized zone present at Garrison was not included in the resource estimate reported by the previous operator in 2013. Mineralization at the 903 was discovered in 1945 by Wright-Hargreaves Mines Ltd. In 1988 Lac Minerals acquired the claims covering the current 903 Zone and completed 17 drill holes totaling 4,823 metres. The property was optioned in 1990 to Jonpol and T&H Resources and subsequently returned to Lac Minerals in 1991. Northern Gold acquired the claims from a subsidiary of Barrick Gold in 2013, conducting surface exploration and six drill holes.

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-dOr 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 3,300 square kilometres), a 100% interest in the Marban project located in the heart of Québecs 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 Québec and Ontario.  Osisko continues to be well financed with approximately $190 million in cash and investments as of the end of Q4 2017.

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 timing and ability (if at all) of Osisko to prepare a Preliminary Economic Assessment and initial resource estimate for the Windfall deposit; the timing and ability (if at all) of Osisko to prepare a feasibility study for the Windfall deposit; Osiskos exploration budget for 2018; the advancement of the Windfall and Lynx deposits through drilling and exploration initiatives; the expansion of the previously known mineralized zones and the discovery of the new Lynx deposit, and Wolf and Bobcat zones; continued exploration and drilling at the Windfall and Lynx deposits and any extension of the mineralized zones; the continued advancement, and rate of advancement, of the exploration ramp; the timing and ability (if at all) of Osisko to obtain permits for the exploration ramp towards Lynx; the ability of the Windfall Lake gold project to be one of the highest-grade resource stage gold projects in Canada; the significance of drill results from the ongoing drill program at the Windfall Lake gold project; the timing and ability (if at all) of Osisko to complete additional property acquisitions in Lebel-sur-Quévillon; the benefits of a potential processing plant in Lebel-sur-Quévillon; the timing and ability (if at all) of Osisko to prepare  an initial resource estimate in respect of the Osborne-Bell deposit; exploration planned at the Fox and Black Dog discoveries; proposed exploration work at the Urban Barry block; proposed exploration work on the Quévillon block; the continued fast pace of our work in 2018; our ability to sustain and add shareholder value; Osiskos ability (if at all) to develop into a mining camp; the type of drilling included in the drill program; potential mineralization; 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; 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”, “managements 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. This forward-looking information involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements to be materially different from any 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 to accurately predict mineralization; errors in managements geological modelling; delays in the turnaround of assay data; lack of adequate drill density; Osiskos timing and ability (if at all) to complete further exploration activities, including drilling; property interests in the Windfall Lake gold project and Osborne-Bell gold deposit; 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.

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

Osisko Mining Provides Quebec Exploration Update

(Toronto, February 8, 2018)  Osisko Mining Inc. (OSK:TSX) (“Osisko” or the “Corporation”) is pleased to provide an update on the progress of exploration at its 100% owned Windfall Lake, Urban Barry and Quévillon gold projects located in the Abitibi greenstone belt, Eeyou Istchee James Bay, Québec.

Osisko has been conducting new exploration and definition drilling at Windfall for 26 months, since late October 2015.  As of the end of January 2018, Osisko has completed 518,000 metres of the planned 800,000 metres to complement the pre-existing 180,000 metres drilled at Windfall by previous operators. 

The company is rapidly advancing the Windfall and Lynx deposits through a balance of resource delineation drilling and exploration drilling for extensions and new mineralized zones.  Osisko has been successful in the past two years at significantly expanding the known areas of mineralization in the Windfall system and reinterpreting the geological model of the Windfall deposit.  Drilling over the past 18 months has been directed by the evolving intrusion-related geological model, leading to the discovery of significant extensions of the previously known mineralized zones, and to the discovery of the new Lynx deposit, Wolf and Bobcat zones.

Exploration Budget for 2018:  $100M
Osisko’s 2018 exploration budget for the Windfall/Lynx deposits, Urban Barry and Quévillon project areas totals approximately $100 million.  This budget includes resource estimation work, resource-oriented drilling, exploration ramp and underground bulk sampling of known mineralized zones, metallurgical work, permitting, PEA and feasibility studies, exploration drilling proximal to Windfall and Lynx, and exploration drilling on the greater Urban Barry and Quévillon properties.

Windfall/Lynx:  Initial Resource Estimation Planned for May 2018, PEA Planned for June 2018
Osisko’s initial resource for Windfall is scheduled to be released in early May, a delay of six weeks from the previous Q1 2018 estimated completion, due to the slower than anticipated turnaround of assay data.  Osisko plans to have a Preliminary Economic Assessment completed in June 2018 for the Windfall deposit subsequent to the release of the initial resource estimate.

The main Windfall deposit and the Lynx deposit (discovered by Osisko in early 2017) remain open to the NE and at depth, and surface exploration drilling is continuing.  Newly discovered extensions of the main Windfall deposit (Caribou Extension, Zone 27 Extension, Underdog Expansion), and part of the Lynx deposit and its sub zones below 350 metres depth and further northeast of section 3750E, will not be included in the May 2018 resource estimate, due to lack of adequate drill density.  Infill drilling planned for the balance of 2018 will be focused on these areas, with the aim of including them in a planned Q1 2019 feasibility study.

The Corporation will continue significant exploration drilling at Windfall and Lynx through the balance of 2018 as it moves towards the feasibility study, and will continue drilling at the main Windfall and Lynx deposit to infill and extend the mineralized zones defined to date.

Windfall Exploration Ramp Progress
Dewatering of the historic exploration ramp was completed at the end of August 2017, and rehabilitation of the portal began in September. To date, 1,021 metres of rehabilitation have been completed. The remaining areas of the pre-existing exploration ramp are non-essential and will be rehabilitated as necessary.

The first underground blast was completed in late October (see October 27, 2017 press release). Underground infrastructure completed to date includes 45 metres of development for powder and cap magazines and 48 metres of slashes and safety bays. Three electrical substations have been installed as well as a water basin for future water treatment.

New advance towards the Main Zone commenced in late December, with 136 metres completed to date. The rate of advance is approximately 150 metres per month.  Bulk sampling in Zone 27, Caribou and Underdog is anticipated to occur in Q2 2018, Q3 2018 and Q4 2019 respectively.

Permits for the exploration ramp towards Lynx are anticipated in Q2 2018. Approximately 1,200 metres of exploration ramp extension are planned to reach Lynx.  Bulk sampling in Lynx is anticipated to occur in Q1 2019.

Property Acquisition in Lebel-sur-Quévillon
An alternatives assessment, considering environmental, technical, social and economic factors, has been completed on the location of the potential processing plant for the Windfall Project. The preferred option for the location of the potential processing plant is in the municipality of Lebel-sur-Quévillon (partially on the former Domtar site) and in the territory of Eeyou Istchee James Bay, Québec. The acquisition of approximately 560 hectares of property is expected to be finalized in Q1 2018. The proximity to a stable workforce and existing infrastructure, including power and water supply with available capacity were important components in the evaluation.

Osborne-Bell:  Initial Resource Estimation Planned for April 2018
Osisko commenced new drilling at the Osborne-Bell deposit with two rigs in early December 2017.  Re-evaluation of the approximately 200,000 metres of historical drilling results from previous operators and the addition of new information from Osisko’s drilling will be used to produce an initial resource, anticipated to be released in early April 2018.  Osborne-Bell is located approximately 20 kilometres northwest of the town of Lebel-sur-Quévillon.

Exploration Planned for Fox and Black Dog
A review of the exploration work conducted by Osisko in 2016 and 2017 at the Fox and Black Dog discoveries, within the context of the evolving geological model for the main Windfall deposit is currently under way.  New exploration drilling is planned for the two areas in H2 2018.

Exploration on the Urban Barry Block
Osisko has completed base line exploration programs on the Urban Barry block including airborne geophysics, ground geophysics, geological mapping and sampling and basal till sampling, developing a significant number of targets (over 100).  Osisko intends to include exploration drilling on priority targets developed by these base line programs in the course of 2018 work.

Exploration on the Quévillon Block
Osisko acquired the Quévillon Block in early 2017, and commenced the collection of base line exploration data including airborne geophysics, geological mapping and sampling, and basal till sampling.  The continuing work is approximately one-third complete, with several significant exploration targets already developed from both historical drilling and the new information collected.  Osisko intends to include exploration drilling on priority targets developed by these programs in the course of 2018 work.

President and CEO of Osisko John Burzynski commented: “We have been moving the Windfall project forward at a very quick pace since our first work started in late 2015.  We have added significant shareholder value through our substantial drilling and exploration programs at Windfall, with the discovery of the Lynx deposit and new previously unknown extensions of the main Windfall zones.  We plan to continue the fast pace of work on all of our projects in 2018 with over 20 active drills, and are eagerly anticipating the release of our first resource estimate for Windfall-Lynx in early May.  We will prepare a Preliminary Economic Assessment for Windfall-Lynx for June 2018 following the anticipated resource estimate, and will continue our exploration of the deposits through surface drilling and the progression of the exploration ramp, with the goal of moving to a feasibility study for Windfall in early 2019.  Property-wide exploration on our bank of existing targets will also resume in 2018, with the goal of adding new discoveries to our growing inventory of “drill bit success” at Windfall.  We will have another very busy year, with an exploration budget of approximately $100 million, and will continue to be the most active explorer in Québec in what we believe is a new developing mining camp.”

About the Windfall Lake Gold Deposit
The Windfall Lake gold deposit is located between Val-dOr 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-dOr 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 3,300 square kilometres), a 100% interest in the Marban project located in the heart of Québecs 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 Québec and Ontario.  Osisko continues to be well financed with approximately $190 million in cash and investments as of the end of Q4 2017.

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 timing and ability (if at all) of Osisko to prepare a Preliminary Economic Assessment and initial resource estimate for the Windfall deposit; the timing and ability (if at all) of Osisko to prepare a feasibility study for the Windfall deposit; Osiskos exploration budget for 2018; the advancement of the Windfall and Lynx deposits through drilling and exploration initiatives; the expansion of the previously known mineralized zones and the discovery of the new Lynx deposit, and Wolf and Bobcat zones; continued exploration and drilling at the Windfall and Lynx deposits and any extension of the mineralized zones; the continued advancement, and rate of advancement, of the exploration ramp; the timing and ability (if at all) of Osisko to obtain permits for the exploration ramp towards Lynx; the ability of the Windfall Lake gold project to be one of the highest-grade resource stage gold projects in Canada; the significance of drill results from the ongoing drill program at the Windfall Lake gold project; the timing and ability (if at all) of Osisko to complete additional property acquisitions in Lebel-sur-Quévillon; the benefits of a potential processing plant in Lebel-sur-Quévillon; the timing and ability (if at all) of Osisko to prepare  an initial resource estimate in respect of the Osborne-Bell deposit; exploration planned at the Fox and Black Dog discoveries; proposed exploration work at the Urban Barry block; proposed exploration work on the Quévillon block; the continued fast pace of our work in 2018; our ability to sustain and add shareholder value; Osiskos ability (if at all) to develop into a mining camp; the type of drilling included in the drill program; potential mineralization; 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; 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”, “managements 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. This forward-looking information involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements to be materially different from any 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 to accurately predict mineralization; errors in managements geological modelling; delays in the turnaround of assay data; lack of adequate drill density; Osiskos timing and ability (if at all) to complete further exploration activities, including drilling; property interests in the Windfall Lake gold project and Osborne-Bell gold deposit; 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.

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

Osisko Mining Inc. Files Early Warning Report in Respect of Beaufield Resources Inc.

Toronto, Ontario (January 10, 2018) – Osisko Mining Inc. (TSX: OSK) (the “Corporation“) announces that it has filed an early warning report in respect of its holdings in Beaufield Resources Inc. (“Beaufield“). The Corporation, through its wholly-owned subsidiary O3 Investments Inc., acquired beneficial ownership of, or control and direction over, 16,923,500 common shares of Beaufield (collectively, the “Purchased Shares” and each, a “Purchased Share“) by way of a share purchase agreement transaction (and not through the facilities of the TSX Venture Exchange), representing approximately 8.2% of the issued and outstanding common shares of Beaufield (“BFD Shares“) at a price of $0.14 per BFD Share for total consideration of $2,369,290 (the “Purchase“). After giving effect to the Purchase, the Corporation, through its wholly-owned subsidiary O3 Investments Inc., acquired beneficial ownership of, or control and direction over, additional BFD Shares in an amount equal to more than 2% of the outstanding BFD Shares, thereby triggering the requirement to file an early warning report.

Prior to giving effect to the Purchase, the Corporation, through its wholly-owned subsidiary O3 Investments Inc., held beneficial ownership of, or control and direction over, 39,197,300 BFD Shares, representing approximately 18.8% of the number of issued and outstanding BFD Shares. After giving effect to the Purchase, the Corporation, through its wholly-owned subsidiary O3 Investments Inc., held beneficial ownership of, or control and direction over, 56,181,300 BFD Shares, representing approximately 27.0% of the number of issued and outstanding BFD Shares.

The Corporation, through its wholly-owned subsidiary O3 Investments Inc., acquired the Purchased Shares for investment purposes. The Corporation has no current intention of increasing or decreasing its ownership of, or control or direction over, additional securities of Beaufield. The Corporation reviews its holdings from time to time and may increase or decrease its position as future circumstances may dictate.

The Corporation completed the Purchase in reliance on the private agreement exemption in section 4.2 of National Instrument 62-104 – Take-Over Bids and Issuer Bids (“NI 62-104“). The Corporation purchased the Purchased Shares from fewer than 5 sellers and at a price less than 115% of the market price, in each case as calculated in NI 62-104.

This news release is being issued in accordance with National Instrument 62-103 – The Early Warning System and Related Take-Over Bid and Insider Reporting Issues in connection with the filing of an early warning report dated January 10, 2018. The early warning report respecting the Purchase has been filed on System for Electronic Document Analysis and Review (“SEDAR“) at www.sedar.com under Beaufields issuer profile. To obtain a copy of the early warning report filed by the Corporation, please contact John Burzynski at (416) 363-8653 or refer to the SEDAR at www.sedar.com under Beaufields issuer profile.

For further information on the Corporation please contact:

John Burzynski
President & Chief Executive Officer
Telephone: (416) 363-8653

The Corporations head office is located at 155 University Avenue, Suite 1440, Toronto, Ontario M5H 3B7.

Osisko Announces TSX Approval Of Normal Course Issuer Bid

(Toronto, December 21, 2017) Osisko Mining Inc. (TSX:OSK) (the “Corporation” or “Osisko“) today announces that the Toronto Stock Exchange (the “TSX“) has approved the Corporations notice of intention to make a normal course issuer bid (the “NCIB Program“). Under the terms of the NCIB Program, Osisko may acquire up to 15,204,587 of its common shares (“Common Shares“) from time to time in accordance with the normal course issuer bid procedures of the TSX. Any repurchases under the NCIB Program will be made in Canada through the facilities of the TSX.

Repurchases under the NCIB Program may commence on December 29, 2017 and will terminate on December 28, 2018 or on such earlier date as the NCIB Program is complete. Purchases of Common Shares under the NCIB Program will be made in Canada through the facilities of the TSX in accordance with its rules. Daily purchases will be limited to 162,895 Common Shares, other than block purchase exemptions, representing 25% of the average daily trading volume of the Common Shares on the TSX for the six month period ending November 30, 2017, being 651,581 Common Shares.

The price that the Corporation may pay for any Common Shares purchased under the NCIB Program will be the prevailing market price at the time of purchase and any Common Shares purchased by the Corporation will be cancelled.  The board of directors of Osisko believes that the underlying value of the Corporation may not be reflected in the market price of the Common Shares from time to time and that, accordingly, the purchase of Common Shares will increase the proportionate interest in the Corporation of, and be advantageous to, all remaining shareholders of the Corporation.

As of December 18, 2017, there were 207,586,907 Common Shares issued and outstanding. The 15,204,587 Common Shares that may be repurchased under the NCIB Program represent approximately 10% of the public float of the Corporation as of December 18, 2017, being 152,045,876 Common Shares.

Osisko has appointed BMO Nesbitt Burns Inc. to make any purchases under the NCIB Program on its behalf.

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-dOr 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 Québecs 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 $190 million in cash and investments.

Forward-looking statements

This press release contains forward-looking statements. These forward-looking statements, by their nature, require the Corporation to make certain assumptions and necessarily involve known and unknown risks and uncertainties that could cause actual results to differ materially from those expressed or implied in these forward-looking statements. Words such as “may”, “will”, “would”, “could”, “expect”, “believe”, “plan”, “anticipate”, “intend”, “estimate”, “continue”, or the negative or comparable terminology, as well as terms usually used in the future and the conditional, are intended to identify forward-looking statements including the fact that the Corporation “expects”, “plans”, “anticipates”, “believes”, “intends”, “estimates”, “projects”, “potential”, “scheduled” and similar expressions or variations (including negative variations), or that events or conditions “will”, “would”, “may”, “could” or “should” occur including, without limitation, statements about the board of directors of Osiskos belief that the NCIB Program is advantageous to shareholders and that underlying value of the Corporation may not be reflected in the market price of the Common Shares, the Corporations intentions regarding the NCIB Program and whether the Corporation will receive the requisite acceptance of the TSX in respect of the NCIB Program. Although Osisko believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements involve known and unknown risks, uncertainties and other factors and are not guarantees of future performance and actual results may accordingly differ materially from those in forward looking statements. Factors that could cause the actual results to differ materially from those in forward-looking statements include, without limitation: fluctuations in the prices of the commodities; fluctuations in the value of the Canadian dollar relative to the U.S. dollar; regulatory changes by national and local government, including corporate law, permitting and licensing regimes and taxation policies; continued availability of capital and financing and general economic, market or business conditions; business opportunities that become available to, or are pursued by Osisko; other uninsured risks. The forward looking statements contained in this press release are based upon assumptions management believes to be reasonable, including, without limitation: the ability of exploration activities (including drill results) to accurately predict mineralization; errors in managements 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.

For further information, please contact Osisko Mining Inc.:

John Burzynski
President and Chief Executive Officer
Telephone: (416) 363-8653

Osisko Announces Intention to Implement Normal Course Issuer Bid

(Toronto, December 19, 2017) Osisko Mining Inc. (TSX:OSK) (the “Corporation” or “Osisko“) today announces its intention to implement a normal course issuer bid program to purchase for cancellation, from time to time over a 12-month period, common shares of the Corporation (“Common Shares“) listed on the Toronto Stock Exchange (“TSX“) in an aggregate amount of up to 10% of the public float of the Corporation (the “NCIB Program“). The commencement of the NCIB Program is subject to TSX approval.

Any repurchases under the NCIB Program will be made in Canada through the facilities of the TSX. Osisko will pay the prevailing market price at the time of purchase. The actual number of Common Shares repurchased under the NCIB Program and the timing of such repurchases will be at Osiskos discretion and shall be subject to the limitations set out in the TSX Company Manual.

The board of directors of Osisko believes that the underlying value of the Corporation may not be reflected in the market price of the Common Shares from time to time and that, accordingly, the purchase of Common Shares will increase the proportionate interest in the Corporation of, and be advantageous to, all remaining shareholders of the Corporation.

As of December 18, 2017, there were 207,586,907 Common Shares issued and outstanding, and the Corporation had a public float of 152,045,876 Common Shares.

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-dOr 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 Québecs 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 $190 million in cash and investments.

Forward-looking statements

This press release contains forward-looking statements. These forward-looking statements, by their nature, require the Corporation to make certain assumptions and necessarily involve known and unknown risks and uncertainties that could cause actual results to differ materially from those expressed or implied in these forward-looking statements. Words such as “may”, “will”, “would”, “could”, “expect”, “believe”, “plan”, “anticipate”, “intend”, “estimate”, “continue”, or the negative or comparable terminology, as well as terms usually used in the future and the conditional, are intended to identify forward-looking statements including the fact that the Corporation “expects”, “plans”, “anticipates”, “believes”, “intends”, “estimates”, “projects”, “potential”, “scheduled” and similar expressions or variations (including negative variations), or that events or conditions “will”, “would”, “may”, “could” or “should” occur including, without limitation, statements about the board of directors of Osiskos belief that the NCIB Program is advantageous to shareholders and that underlying value of the Corporation may not be reflected in the market price of the Common Shares, the Corporations intentions regarding the NCIB Program and whether the Corporation will receive the requisite acceptance of the TSX in respect of the NCIB Program. Although Osisko believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements involve known and unknown risks, uncertainties and other factors and are not guarantees of future performance and actual results may accordingly differ materially from those in forward looking statements. Factors that could cause the actual results to differ materially from those in forward-looking statements include, without limitation: fluctuations in the prices of the commodities; fluctuations in the value of the Canadian dollar relative to the U.S. dollar; regulatory changes by national and local government, including corporate law, permitting and licensing regimes and taxation policies; continued availability of capital and financing and general economic, market or business conditions; business opportunities that become available to, or are pursued by Osisko; other uninsured risks. The forward looking statements contained in this press release are based upon assumptions management believes to be reasonable, including, without limitation: the ability of exploration activities (including drill results) to accurately predict mineralization; errors in managements 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.

For further information, please contact Osisko Mining Inc.:

John Burzynski
President and Chief Executive Officer
Telephone: (416) 363-8653

Osisko Commences Drill Program At Osborne-Bell

(Toronto, December 14, 2017)  Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to announce it has commenced drilling with two drill rigs on its 100% owned Osborne-Bell gold deposit located in the Abitibi greenstone belt, Quévillon Township, Eeyou Istchee James Bay Region, Québec. Located 17 kilometres northwest of the town of Lebel-sur-Quévillon and 112 kilometres west of the Windfall Lake gold deposit, Osborne-Bell is part of Osiskos Quévillon Project, which consists of a 2160 square kilometer land package hosting approximately thirty known gold showings.  A map showing the location of the deposit and project is posted on our website at www.osiskomining.com.

The 50,000 metre drill program will re-evaluate the historical Osborne-Bell resource, and test regional exploration targets on the Quévillon Project.  The Osborne-Bell deposit has seen significant historical drilling, which Osisko intends to re-log as part of the ongoing program.

The Company is also currently completing a 27,000 kilometre high-definition magnetic survey and 5,400 kilometre V-TEM airborne survey over the Quévillon Project.

Qualified Person
The scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Mathieu Savard, B.Sc., P.Geo. (OGQ 510), Vice President Exploration – Québec, who is a “qualified person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

About the Osborne-Bell Gold Deposit
The Osborne-Bell gold deposit is located 15 km north-west of Lebel-sur-Quevillon and 115 km to the west of the Windfall Lake gold deposit. A resource estimate was completed by Maudore Minerals Ltd on the Osborne-Bell gold deposit on October 26, 2012 (see press release on October 29, 2012 at www.sedar.com) which refers to an indicated mineral resource of 8,463,800 Tonnes at 2.0 g/t Au for 546,299 oz and an inferred mineral resource of 8,115,800 Tonnes at 4.8 g/t Au for 1,258,990 oz. During the acquisition of the Osborne-Bell gold deposit from Deloitte Restructuring in March 2017, Osisko had access to confidential information indicating that the historic mineral resource estimate for the Osborne-Bell gold deposit could possibly be significantly reduced. Osisko intends to explore the Quevillon project and unlock the potential of the newly acquired Quevillon project as well as the Osborne-Bell gold deposit.

For further details regarding the 2012 mineral resource estimate, key assumptions, parameters and methods used to estimate the mineral resources presented in respect of the Osborne-Bell Gold Deposit of the Comtois Property, please see the ” 43-101 Technical Report and Mineral Resource Estimate – Osbell Deposit, Comtois Property”, dated effective date October 26, 2012 and filed on SEDAR on December 7, 2012 under the issuer profile of Maudore Minerals Ltd at www.sedar.com.

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-dOr 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 Québecs 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 $190 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 Osborne-Bell gold deposit and Quévillon project; the current 50,000 metres drill program; the significance of results from the ongoing drill program at the Quévillon project; the significance of the thirty known gold showings, if any; the significance of the high-definition magnetic survey and V-TEM airborne survey over the Quévillon Project, if any; the type of drilling included in the drill program; potential mineralization; 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; 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”, “managements 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. This 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, high-definition magnetic surveys and V-TEM airborne surveys) to accurately predict mineralization; errors in managements geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests in the Osborne-Bell gold deposit and Windfall Lake gold project; 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.

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

Osisko Mining Closes “Bought Deal” Private Placement Of Flow Through Shares For Ontario Properties

(Toronto, December 12, 2017) – Osisko Mining Inc. (TSX:OSK) (“Osisko” or the “Corporation”) is pleased to announce, that it has completed a “bought deal” brokered private placement of an aggregate 479,550 common shares of the Corporation that will qualify as “flow-through shares” (within the meaning of subsection 66(15) of the Income Tax Act (Canada)) (“Flow-Through Shares”), at an issue price of $4.80 per Common Share for aggregate gross proceeds of approximately $2.3 million (the “Offering”). Canaccord Genuity Corp. acted as sole underwriter and sole bookrunner in connection with the Offering.

The gross proceeds from the sale of Flow-Through Shares will be used to fund “Canadian exploration expenses” (within the meaning of the Income Tax Act (Canada)) related to Osiskos projects in Ontario on or prior to December 31, 2018 for renunciation to subscribers of Flow-Through Shares effective December 31, 2017.

All securities issued under the Offering will be subject to a hold period expiring four months and one day from the date hereof. The securities offered have not been registered under the U.S. Securities Act of 1933, as amended, and may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirements. This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of the securities in any State in which such offer, solicitation or sale would be unlawful.

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-dOr 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 Québecs 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 $190 million in cash and investments.

Cautionary Note Regarding Forward-Looking Information

This news release contains “forward-looking information” within the meaning of applicable Canadian securities legislation based on expectations, estimates and projections as at the date of this news release. Forward-looking information involves risks, uncertainties and other factors that could cause actual events, results, performance, prospects and opportunities to differ materially from those expressed or implied by such forward-looking information. Forward-looking information in this news release includes, but is not limited to, the use of proceeds of the Offering; the timing and ability of the Corporation, if at all, to obtain final approval of the Offering from the Toronto Stock Exchange; objectives, goals or future plans; statements regarding exploration results and exploration plans. Factors that could cause actual results to differ materially from such forward-looking information include, but are not limited to, capital and operating costs varying significantly from estimates; the preliminary nature of metallurgical test results; delays in obtaining or failures to obtain required governmental, environmental or other project approvals; uncertainties relating to the availability and costs of financing needed in the future; changes in equity markets; inflation; fluctuations in commodity prices; delays in the development of projects; the other risks involved in the mineral exploration and development industry; and those risks set out in the Corporations public documents filed on SEDAR at www.sedar.com. Although the Corporation believes that the assumptions and factors used in preparing the forward-looking information in this news release are reasonable, undue reliance should not be placed on such information, which only applies as of the date of this news release, and no assurance can be given that such events will occur in the disclosed time frames or at all. The Corporation disclaims any intention or obligation to update or revise any forward-looking information, whether as a result of new information, future events or otherwise, other than as required by law.

For further information please contact:

John Burzynski
President and Chief Executive Officer
Telephone: (416) 363-8653

Osisko Caribou Extension Increases To 1.2 Kilometres At Windfall

Wolf Zone Extended 200 Metres to NE

High-Grade Infill and Expansion Intercepts Continue

(Toronto, November 16, 2017)  Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new results from the ongoing drill program at its 100% owned Windfall Lake gold project located in Urban Township, Abitibi, Québec.  The 800,000 metre drill program combines definition, expansion and exploration drilling in and around the main Windfall gold deposit and the adjacent Lynx deposit (located immediately NE of Windfall).  Significant new analytical results from 59 intercepts in 35 drill holes focused on infill and expansion drilling in the Underdog, Caribou, Zone 27 and Mallard corridors of the Windfall deposit are presented below.

Highlights from the new results include: 204 g/t Au over 2.0 metres in OSK-W-17-936-W1; and 11.0 g/t Au over 11.2 metres in OSK-W-17-1105 in the Caribou Corridor; 87.0 g/t Au over 2.4 metres in OSK-W-17-866-W2 and 43.9 g/t Au over 3.0 metres in OSK-W-17-833-W2 in the Underdog Corridor; and 36.1 g/t over 4.0 metres in OSK-W-17-903 in Zone 27. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Hole Number From
(m)
To
(m)
Interval
(m)
Au (g/t)
uncut
Au (g/t)
cut to
100 g/t
Zone Corridor
OSK-OBM-16-660 573.9 576.8 2.9 15.0   FW3U Underdog
including 573.9 575.0 1.1 17.9  
including 576.0 576.8 0.8 22.8  
OSK-W-17-833-W1 1089.0 1091.9 2.9 8.24   FW3 Underdog
including 1091.6 1091.9 0.3 76.2  
OSK-W-17-833-W2 1014.0 1017.0 3.0 43.9 41.6 FW2 Underdog
including 1014.7 1016.4 1.7 72.8 68.7
including 1014.7 1015.0 0.3 123 100
OSK-W-17-847-W2 1075.1 1077.2 2.1 10.7   QTV Underdog
including 1075.1 1075.5 0.4 51.1  
OSK-W-17-866-W2 943.5 946.5 3.0 11.6   FW0 Underdog
including 946.1 946.5 0.4 44  
  964.0 966.4 2.4 13.0   FW0 FW Underdog
including 965.1 965.6 0.5 31.1  
  1056.0 1062.0 6.0 4.21   FW1 Underdog
including 1060.5 1062.0 1.5 12.6  
  1095.5 1097.7 2.2 5.4   FW1 Underdog
including 1096.3 1096.7 0.4 29  
  1126.1 1128.5 2.4 87.0 37.4 FW3 Underdog
including 1126.1 1126.9 0.8 249 100
OSK-W-17-885 472.0 474.0 2.0 21.4 19.8 Vein Caribou
including 472.9 473.2 0.3 111 100
  1051.0 1053.0 2.0 7.81   FW0 Underdog
including 1051.0 1052.0 1.0 15.5  
OSK-W-17-885-W1 1056.4 1061.0 4.6 5.24   FW0 HW Underdog
including 1060.0 1061.0 1.0 14.3  
  1237.0 1239.0 2.0 5.95   FW1 HW Underdog
including 1237.7 1238.5 0.8 11.2  
  1340.0 1345.8 5.8 5.19   FW1 Underdog
including 1340.0 1341.0 1.0 15.6  
including 1345.4 1345.8 0.4 17.8  
OSK-W-17-903 539.0 543.0 4.0 36.1 34.2 Z27 Z27
including 539.0 540.0 1.0 108 100
OSK-W-17-903-W2 688.4 690.9 2.5 3.22   FW3U Underdog
including 689.8 690.4 0.6 9.47  
OSK-W-17-936-W1 617.3 619.3 2.0 12.6   Wolf HW Caribou
including 617.3 618.3 1.0 21.3  
  640.8 643.0 2.2 14.2   Wolf Caribou
including 642.4 643.0 0.6 49.2  
  668.5 670.6 2.1 3.55   Wolf Caribou
including 668.9 669.3 0.4 16.9  
  697.0 699.0 2.0 204 50.5 Wolf FW Caribou
including 697.0 698.0 1.0 407 100
  704.0 706.0 2.0 14.8   Wolf FW Caribou
including 705.0 706.0 1.0 29.0  
OSK-W-17-936-W2 574.5 577.9 3.4 3.36   Wolf 2 Caribou
  693.9 695.9 2.0 27.7   VNCR Caribou
including 694.9 695.9 1.0 55.4  
  701.6 703.6 2.0 5.8   Wolf Caribou
  735.0 738.3 3.3 6.41   Wolf FW Caribou
including 735.0 735.9 0.9 14.6  
including 738.0 738.3 0.3 16.3  
OSK-W-17-937-W1 583.0 585.6 2.6 14.6   CS1 HW Caribou
including 583.8 584.9 1.1 34.1  
OSK-W-17-975 424.0 426.5 2.5 4.05   Caribou Ext. Caribou
including 424.6 425.0 0.4 23.2  
OSK-W-17-977 386.2 389.0 2.8 3.39   New Zone Underdog
including 386.2 387.0 0.8 9.92  
OSK-W-17-1009 127.9 130.0 2.1 3.16   Z27 Z27
OSK-W-17-1051 1096.7 1099.0 2.3 5.22   FW1 Underdog
including 1097.5 1098.0 0.5 17.5  
  1103.0 1105.4 2.4 7.09   FW1 Underdog
including 1104.0 1104.4 0.4 34.6  
  1111.0 1114.5 3.5 6.82   FW1 Underdog
including 1113.9 1114.5 0.6 29.7  
OSK-W-17-1051-W2 1081.5 1085.5 4.0 11.8   FW1 Underdog
including 1081.5 1082.0 0.5 52.4  
  1119.1 1121.3 2.2 7.19   FW1 FW Underdog
OSK-W-17-1081 61.3 63.7 2.4 10.4   Z27 Z27
including 62.0 62.6 0.6 35.2  
OSK-W-17-1087 243.0 245.0 2.0 3.28   Drake Mallard
OSK-W-17-1088 80.2 82.4 2.2 7.73   Z27 Z27
including 80.2 81.0 0.8 19.5  
OSK-W-17-1105 526.0 528.0 2.0 8.85   Caribou Ext. Caribou
including 527.5 528.0 0.5 17.3  
  534.3 539.0 4.7 4.94   Caribou Ext. Caribou
including 534.3 535.0 0.7 14.5  
  556.2 558.5 2.3 4.21   Caribou Ext. Caribou
  684.9 696.1 11.2 11.0 7.95 Wolf FW Caribou
including 684.9 689.8 4.9 21.4 14.5
OSK-W-17-1110 460.6 465.3 4.7 4.39   CS1 Caribou
including 460.6 461.2 0.6 12.4  
OSK-W-17-1115 333.6 336.4 2.8 13.7   New Zone  
OSK-W-17-1116 63.0 66.0 3.0 9.13   Z27 Z27
including 63.0 64.0 1.0 21.1  
OSK-W-17-1125-W3 583.0 585.0 2.0 11.5   Wolf FW Caribou
including 583.8 584.2 0.4 49.6  
OSK-W-17-1137 56.5 58.5 2.0 3.01   Z27 Z27
OSK-W-17-1138 142.0 158.0 16.0 6.3   VNCR Caribou
OSK-W-17-1145 90.9 93.3 2.4 12.5   Z27 Z27
  95.6 100.4 4.8 9.93   Z27 Z27
  120.0 125.9 5.9 7.25   Z27 Z27
OSK-W-17-1177 1353.1 1356.5 3.4 7.86   Caribou Ext. Caribou
including 1354.1 1355.1 1.0 17.1  
OSK-W-17-1224 371.0 373.4 2.4 3.12   Mallard Mallard
OSK-W-17-1226 717.0 721.6 4.6 8.29   New Zone Caribou
OSK-W-17-1232 206.0 208.0 2.0 27.2   Z27 Z27
OSK-W-17-1241 22.0 25.5 3.5 8.11   Caribou Ext. Caribou
including 24.6 25.5 0.9 17.9  
OSK-W-17-1252 168.0 170.0 2.0 8.38   New Zone  
including 168.0 169.0 1.0 16.7  
OSK-W-17-1257 155.5 157.6 2.1 7.69   Z27 Z27
including 156.2 156.5 0.3 44.9  
  161.0 163.3 2.3 3.15   Z27 Z27
including 163.0 163.3 0.3 17.2  
  172.0 174.0 2.0 15.4   Z27 Z27
including 172.0 173.0 1.0 30.1  

Notes:

  1. True widths are estimated at 65 – 80% of the reported core length interval.  See “Quality Control” below.
  2. Definitions: FW = Foot Wall, HW = Hanging Wall, QTV = Quartz-Tourmaline Vein, VNCR = Crustiform Vein, Ext. = Extension
Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Section
OSK-OBM-16-660 329 -52 651 452376 5434668 2500
OSK-W-17-833-W1 331 -57 1173 452597 5434393 2550
OSK-W-17-833-W2 331 -57 1244 452597 5434393 2550
OSK-W-17-847-W2 334 -69 1275 452645 5434429 2625
OSK-W-17-866-W2 332 -57 1332 452633 5434280 2525
OSK-W-17-885 335 -67 1458 452861 5434494 2850
OSK-W-17-885-W1 335 -67 1383 452861 5434494 2850
OSK-W-17-903 329 -56 801 452539 5434692 2650
OSK-W-17-903-W2 329 -56 795 452539 5434692 2650
OSK-W-17-936-W1 332 -56 808 452773 5434547 2775
OSK-W-17-936-W2 332 -56 819 452773 5434547 2775
OSK-W-17-937-W1 333 -57 945 452897 5434430 2850
OSK-W-17-975 334 -64 804 452862 5434814 3000
OSK-W-17-977 331 -51 540 452207 5434816 2425
OSK-W-17-1009 147 -49 183 452107 5434809 2325
OSK-W-17-1051 138 -68 1248 452313 5435323 2775
OSK-W-17-1051-W2 138 -68 1206 452313 5435323 2775
OSK-W-17-1081 145 -65 117 451987 5434710 2175
OSK-W-17-1087 328 -61 381 452255 5434830 2475
OSK-W-17-1088 148 -55 129 451972 5434737 2175
OSK-W-17-1105 328 -71 834 452920 5434843 3050
OSK-W-17-1110 333 -60 570 452488 5434436 2475
OSK-W-17-1115 153 -48 816 452796 5435118 3075
OSK-W-17-1116 150 -47 123 452039 5434729 2225
OSK-W-17-1125-W3 331 -58 1086 452563 5434568 2625
OSK-W-17-1137 132 -61 81 452136 5434749 2325
OSK-W-17-1138 327 -51 402 452888 5434989 3100
OSK-W-17-1145 146 -49 157 452041 5434769 2250
OSK-W-17-1177 340 -67 1422 454113 5435090 4225
OSK-W-17-1224 333 -70 402 452304 5434914 2550
OSK-W-17-1226 331 -51 934 453371 5434726 3400
OSK-W-17-1232 154 -47 351 452025 5434834 2275
OSK-W-17-1241 130 -45 282 452947 5435107 3225
OSK-W-17-1252 324 -46 231 452132 5434944 2425
OSK-W-17-1257 322 -71 250 452081 5434634 2225

 

OSK-OBM-16-660 intersected 14.1 g/t Au over 2.9 metres in FW3U. Mineralization is composed of up to 5% pyrite stringers and disseminated pyrite hosted in sericitized andesite.

OSK-W-17-833-W1 intersected 8.24 g/t Au over 2.9 metres in FW3. Mineralization is composed of up to 10% pyrite stringers hosted in a strongly sericitized fragmental felsic dike.

OSK-W-17-833-W2 intersected 43.9 g/t Au over 3.0 metres in FW2. Mineralization is composed of up to 15% pyrite stringers, 5% disseminated pyrite and local visible gold. The host rock is a fragmental felsic dike cross-cut by a large quartz eyes porphyritic felsic dike, is strongly silicified and moderately sericitized. The interval extends FW2 25 metres east of OSK-W-16-706-W1 (7.10 g/t Au over 5.0 metres previously reported September 19, 2016).

OSK-W-17-847-W2 intersected 10.7 g/t Au over 2.1 metres within the Underdog Corridor. Mineralization corresponds with decimetres scale quartz-tourmaline veins hosted in a sericitized felsic dike with 3% pyrite, disseminated or in stringers.

OSK-W-17-866-W2 intersected five intervals in the Underdog Corridor: 11.6 g/t Au over 3.0 metres in FW0, 13.0 g/t Au over 2.4 metres in FW0 FW, 4.21 g/t Au over 6.0 metres in FW1; 5.4 g/t Au over 2.2 metres related to FW1 and 87.0 g/t Au over 2.4 metres related to FW3. Mineralization in the first interval is at a sericitized and silicified contact between two felsic intrusions, and is composed of 5% pyrite stringers and 1 % disseminated pyrite. The second and third intervals are composed of 1% disseminated pyrite and pyrite stringers in a sericitized and slightly silicified porphyritic felsic intrusion. The fourth and fifth intervals are composed of 3% disseminated pyrite and 2% pyrite stringers associated with intense pervasive silica flooding hosted within a porphyritic felsic intrusion. Local visible gold is observed in the FW3 zone.

OSK-W-17-885 intersected two intervals: 21.4 g/t Au over 2.0 metres and 7.81 g/t Au over 2.0 metres in FW0. The first interval is 100 m south-east of the Caribou Corridor and composed of local visible gold associated with pyrite-chalcopyrite-tourmaline stringers hosted in the rhyolite. The FW0 interval is composed of 2% disseminated pyrite associated with quartz-pyrite-carbonate veinlets.

OSK-W-17-885-W1 intersected three intervals in the Underdog Corridor: 5.24 g/t Au over 4.6 metres in FW0 HW, 5.95 g/t Au over 2.0 metres in FW1 HW and 5.19 g/t Au over 5.8 metres in FW1. Mineralization is composed of up 3% pyrite stringers and 1% disseminated pyrite in a sericitized and silicified felsic porphyritic dike. The third interval contains trace pyrite stringers with intense silica and sericite alteration. This hole extends FW1 HW to the north-east, 135 metres down plunge of OSK-W-17-821-W1 (4.63 g/t Au over 5.0 metres previously reported August 24, 2017).

OSK-W-17-903 returned 36.1 g/t Au over 4.0 metres in Zone 27. Mineralization is composed of up to 10% pyrite stringers and 5% disseminated pyrite in a moderately sericitized andesite.

OSK-W-17-903-W2 intersected 3.22 /t Au over 2.5 metres in FW3U. Mineralization is composed of 3% pyrite stringers with centimetre scale crustiform veins and quartz-tourmaline veins hosted in a sericitized andesite.

OSK-W-17-936-W1 intersected multiple mineralized zones in the Caribou Corridor: 12.6 g/t Au over 2.0 metres in Wolf HW, 14.2 g/t Au over 2.2 metres and 3.55 g/t Au over 2.1 metres in Wolf, and 204 g/t Au over 2.0 metres and 14.8 g/t over 2.0 metres in Wolf FW. The first two intervals are hosted in a sericitized andesite and composed of up to 10% pyrite stringers and 2% disseminated pyrite. The third interval includes 20% quartz-tourmaline veins associated with a hydrothermal breccia. The fourth and fifth intervals are composed of up to 1% pyrite stringers and 1% disseminated pyrite within a strongly silicified large quartz eyes porphyritic felsic intrusion.

OSK-W-17-936-W2 intersected four intervals in the Caribou Corridor: 3.36 g/t Au over 3.4 metres in Wolf 2, 27.7 g/t Au over 2.0 metres in a crustiform vein, 5.8 g/t Au over 2.0 metres in Wolf, and 6.41 g/t Au over 3.3 metres in Wolf FW. Wolf 2 mineralization and the crustiform vein are hosted in a strongly sericitized andesite and contain up to 8% pyrite stringers in stockwork texture. The Wolf interval contains local visible gold and 1% disseminated pyrite within a large quartz eyes porphyritic felsic intrusion. The last interval, the Wolf FW, is composed of 1% disseminated pyrite and 1% pyrite clusters in a silicified felsic dike.

OSK-W-17-937-W1 returned 14.6 g/t Au over 2.6 metres in CS1 HW. The mineralization is composed of 2% quartz-tourmaline veins and traces of disseminated pyrite. The interval is hosted in a strongly sericitized rhyolite.

OSK-W-17-975 returned 4.05 g/t Au over 2.5 metres in the extension of the Caribou Corridor. The mineralization is composed of trace disseminated pyrite and pyrite stringers in a chloritized andesite near the porphyritic felsic intrusion contact.

OSK-W-17-977 intersected 3.39 g/t Au over 2.8 metres in the Underdog Corridor. Mineralization is composed of trace disseminated and stringer pyrite associated with weak sericite and silica alteration within porphyritic felsic intrusion. This new zone is located just under the Red Dog intrusion, 60 metres north of the Mallard zone. The exact geometry and relationship with the Mallard zone is yet to be determined.

OSK-W-17-1009 returned 3.16 g/t Au over 2.1 metres in Zone 27. Traces of disseminated pyrite and pyrite stringers are associated with sericitized rhyolite.

OSK-W-17-1051 intersected three intervals all in the FW1 zone in the Underdog Corridor. The intervals returned 5.22 g/t Au over 2.3 metres, 7.09 g/t Au over 2.4 metres and 6.82 g/t Au over 3.5 metres in a strongly silicified and moderately sericitized large quartz eyes porphyritic felsic intrusion. The mineralization is composed of up to 25% pyrite stringers and 2% pyrite in silica flooding and up to 2% chalcopyrite. The second interval contains local visible gold.

OSK-W-17-1051-W2 intersected two intervals in the Underdog Corridor: 11.8 g/t Au over 4.0 metres in FW1 and 7.19 g/t Au over 2.2 metres in FW1 FW. The first interval is composed of 10% pyrite stringers and 1% disseminated pyrite associated with a strong silica alteration and hosted in fragmental felsic dike. The second interval is composed of up to 20% pyrite stringers and local visible electrum.

OSK-W-17-1081 returned 10.4 g/t Au over 2.4 metres in Zone 27. Mineralization is hosted in a strongly silicified and weakly sericitized porphyritic felsic dike and composed of up to 5% disseminated pyrite and quartz-tourmaline veins.

OSK-W-17-1087 returned 3.28 g/t Au over 2.0 metres in Drake. Mineralization is composed of 5% pyrite stringers within a sericitized porphyritic felsic dike.

OSK-W-17-1088 returned 7.73 g/t Au over 2.2 metres in Zone 27. Mineralization is composed of up to 10% pyrite within pervasive silica flooding hosted in a porphyritic felsic dike.

OSK-W-17-1105 intersected four intervals in the Caribou Corridor: 8.85 g/t Au over 2.0 metres, 4.94 g/t Au over 4.7 metres and 4.21 g/t Au over 2.3 metres in the extension of Caribou and 11.0 g/t Au over 11.2 metres, in the Wolf FW. The first two intervals are associated with large quartz eyes porphyritic felsic dikes and the mineralization is composed of up to 2% pyrite stringers and clusters. The sulphides content increases up to 15% pyrite stringers in the third interval with the mineralization hosted in a sericitized andesite. The last interval contains 15% pyrite stringers, 5% pyrite clusters and local visible gold associated with a strong sericitized andesite. This interval extends the Wolf FW zone 200m north-east and down plunge of OSK-W-17-913 (13.6 g/t Au over 2.0 metres previously reported September 20, 2017).

OSK-W-17-1110 intersected 4.39 g/t Au over 4.7 metres in the Caribou Corridor. Mineralization is composed of up to 10% pyrite clusters and up to 5% ptygmatic tourmaline veins in pervasive silica flooding. The mineralization is at the contact between an andesite and a porphyritic felsic intrusion.

OSK-W-17-1115 intersected a new zone returning 13.7 g/t Au over 2.8 metres. Mineralization is within a sericitized rhyolite and includes 4% disseminated pyrite, 2% pyrite clusters and disseminated tourmaline. This intersection is near a felsic intrusion and highlights a potential area between the main Caribou and the Lynx down plunge trends.

OSK-W-17-1116 returned 9.13 g/t Au over 3.0 metres in Zone 27. The mineralization is associated to a large quartz eyes porphyritic dike and composed of up to 10% pyrite and tourmaline veins.

OSK-W-17-1125-W3 returned 11.5 g/t Au 2.0 metres in the Wolf FW. Mineralization includes up to 30% pyrite stringers in a strongly sericitized fragmental felsic intrusion.

OSK-W-17-1137 intersected 3.01 g/t Au over 2.0 metres in Zone 27. Mineralization is composed of up to 8% pyrite stringers and up to 10% pyrite clusters within a strongly silicified rhyolite.

OSK-W-17-1138 returned 6.3 g/t Au over 16.0 metres in the Caribou Corridor. The mineralization is composed of 3% pyrite clusters, up to 10% pyrite stringers and disseminated chalcopyrite hosted in fragmental felsic dike and crustiform veins. Strong silica and fuchsite alteration are observed.

OSK-W-17-1145 intersected three intervals in Zone 27: 12.5 g/t Au over 2.4 metres, 9.93 g/t Au over 4.8 metres and 7.25 g/t Au over 5.9 metres. The mineralization is similar in the three intervals including up to 20% pyrite stringers in a strong silica flooding. The mineralization is hosted at the contact between a porphyritic felsic dike and the rhyolite.

OSK-W-17-1177 intersected 7.86 g/t Au over 3.4 metres in the extension of the Caribou Corridor. The mineralization is composed of 5% pyrite stringers associated with strong silica alteration zone within the andesite. This interval extends the Caribou Corridor 975 metres down plunge to the north-east from OSK-W-17-787 (7.21 g/t Au over 6.5 metres previously reported March 22, 2017).  With this new hole, the Caribou Extension has now been traced to section 4075E, 1.2 kilometres north-east from the previous operator’s 2015 resource envelope.

OSK-W-17-1224 returned 3.12 g/t Au over 2.4 metres in Mallard. Mineralization is in strongly sericitized and silicified andesite and composed of 30% quartz-carbonate veins with crustiform textures. The sulphides contain up to 2% disseminated pyrite and up to 7% pyrite stringers.

OSK-W-17-1226 intersected a new zone in the Caribou Corridor. The zone is located under a gabbro intrusion, which has the same orientation as the Red Dog, but above the main Caribou down plunge trend. The interval returned 8.29 g/t Au over 4.6 metres in a sericitized and silicified rhyolite cross-cut by felsic intrusions. The mineralization is composed of 10% pyrite stringers and locally semi-massive pyrite (10 cm wide). This new zone is located 150 metres down plunge of OSK-W-17-838 (731 g/t Au over 2.0 metres and 4.55 g/t Au over 3.0 metres previously reported August 24).

OSK-W-17-1232 returned 27.2 g/t Au over 2.0 metres in Zone 27. The mineralization is composed of 2% disseminated pyrite, 3% pyrite stringers and tourmaline veins in a strongly sericitized rhyolite.

OSK-W-17-1241 intersected 8.11 g/t Au over 3.5 metres in the upper part of the Caribou extension. Mineralization is composed of 5% pyrite stringers within a strongly sericitized fragmental intrusion. The geometry of this interval is yet to be determined.

OSK-W-17-1252 intersected 8.38 g/t Au over 2.0 metres in a new zone located 100 metres north-west of the Mallard Corridor. The mineralization is composed of 3% pyrite stringers and locally 20 centimetres scale pyrite veins within a moderately sericitized andesite.

OSK-W-17-1257 intersected three intervals in Zone 27: 7.69 g/t Au over 2.1 metres, 3.15 g/t Au over 2.3 metres and 15.4 g/t Au over 2.0 metres. The mineralization is at the contact between two porphyritic felsic dikes and is composed of up to 1% pyrite stringers, trace of pyrite clusters and one massive pyrite vein of 20 centimetres.

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 dOr, 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-dOr 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-dOr 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 Québecs 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

Osisko Completes First Blast At Windfall Exploration Ramp

(Toronto, October 27, 2017) Osisko Mining Inc. (OSK:TSX “Osisko” or the “Corporation”) is pleased to announce it has completed its first underground blast on schedule at the exploration ramp at its 100% owned Windfall Lake gold project located in Urban Township, Abitibi, Québec. 

Dewatering of the exploration ramp was completed at the end of August. Rehabilitation is on-going and is planned to be completed in the coming month. Underground infrastructure including construction of a powder magazine and various underground excavations is scheduled to be completed in December. The exploration ramp is expected to advance at a rate of approximately 200 metres per month towards the mineralized zones. Underground work, including bulk sampling (for metallurgical testing and grade confirmation) and underground exploration drilling, will commence in Q1 2018.

About the Windfall Lake Gold Deposit
The Windfall Lake gold deposit is located between Val-dOr 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-dOr 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 Québecs 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 $250 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 underground blasts scheduled at the exploration ramp at the Windfall Lake gold project; ongoing rehabilitation efforts; the timing to complete rehabilitation efforts, if at all; the timing and ability, if at all, to complete the construction of underground infrastructure, including construction of a powder magazine and underground excavations; the expected advancement rate of the exploration ramp; the timing and ability to commence underground work (including bulk sampling and underground exploration drilling); the Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada;  potential mineralization, including mineralization identified near the surface and at depth; 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”, “managements 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 managements geological modelling; the ability of Osisko to complete further exploration activities, including drilling and underground work; property interests in the Windfall Lake gold project; 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.

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