A LEADING CANADIAN GOLD EXPLORATION AND DEVELOPMENT COMPANYA p r i l 2 0 1 9

W W W .OS IS K OM IN IN G .C O M | TS X : OS K

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION

21. See Appendix “A” for full disclosure on Mineral Resources.

This presentation (the "Presentation") contains"forward-looking information" and "forward-lookingstatements" (collectively, "forward-lookingstatements") within the meaning of the applicableCanadian securities legislation. All statements,other than statements of historical fact, areforward-looking statements and are based onexpectations, estimates and projections as at thedate of this Presentation. Any statement thatinvolves discussions with respect to predictions,expectations, beliefs, plans, projections, objectives,assumptions, future events or performance (oftenbut 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 phrasesor stating that certain actions, events or results"may" or "could", "would", "might" or "will" be takento occur or be achieved) are not statements ofhistorical fact and may be forward-lookingstatements.

In this Presentation, forward-looking statementsrelate, among other things, to the marketcapitalization of Osisko Mining Inc. ("Osisko"); thevalue of Osisko's cash and investments; the timingand ability of Osisko to release a resource estimatein respect of the Windfall/Lynx deposit in May2018, if at all; the timing and ability of Osisko torelease an updated Preliminary EconomicAssessment in respect of the Windfall/Osborne Belldeposit in Q2 2018, if at all; the timing and ability ofOsisko to release a feasibility study in respect ofthe Windfall/Lynx deposit in Q1 2019, if at all; thetiming and ability of Osisko to advance theexploration ramp at the Windfall/Lynx deposit; thebulk-sampling program at the Windfall Lake golddeposit, if at all; the prior success of the "OsiskoGroup" in creating strong shareholder value havingany impact on the ability of Osisko to create valuefor shareholders of Osisko; the potential of the

Windfall Lake gold deposit, if any; the proposedexploration activities at the Windfall Lake golddeposit; the target timelines in respect of theWindfall Lake gold deposit and Osisko's ability tomake advance the project quickly; planned drillingat the Windfall Lake gold deposit in January 2018;the major shareholders of Osisko going forward;Québec exploration tax credits; the feasibility of theproposed mill complex at Lebel-sur-Quévillon; thedevelopment of the ramp, if at all; the timing andsuccess of exploration, development andmetallurgical testing activities; the timing, extentand success of mining operations (if any), projectdevelopment and related permitting; the results ofexploration programs; the results of economicanalyses (including the Windfall Lake PEA asdefined below); the ability to expand mineralresources beyond current mineral resourceestimates; opportunities for growth of mineralprojects; estimates of gold prices; the ability toadapt to changes in gold prices; estimates of costs,estimates of planned exploration and developmentexpenditures and estimates of mine developmentand construction. All forward-looking statementsentail various risks and uncertainties that are basedon current expectations and actual results maydiffer materially from those contained in suchinformation.

These uncertainties and risks include, but are notlimited to, risks relating to the ability of explorationactivities (including drill results) to accuratelypredict mineralization; errors in management'sgeological modelling; the ability of Osisko tocomplete further exploration activities, includingdrilling; property interests in the Windfall Lake goldproject; the ability of Osisko to obtain requiredapprovals and complete transactions on termsannounced; the results of exploration activities;risks relating to mining activities; fluctuations inspot and forward prices of gold, silver, base metalsor certain other commodities; fluctuations in

currency markets (such as the Canadian dollar toUnited States dollar exchange rate); change ininternational, national and local government,legislation, taxation, controls, regulations andpolitical or economic developments; risks andhazards associated with the business of mineralexploration, development and mining (includingenvironmental hazards, industrial accidents,unusual or unexpected formations pressures, cave-ins and flooding); inability to obtain adequateinsurance to cover risks and hazards; the presenceof laws and regulations that may imposerestrictions on mining; employee relations;relationships with and claims by local communitiesand indigenous populations; availability ofincreasing costs associated with mining inputs andlabour; the speculative nature of mineralexploration and development (including the risks ofobtaining necessary licenses, permits andapprovals from government authorities); and title toproperties. Risks and uncertainties about Osisko'sbusiness are more fully discussed in the disclosurematerials filed with the securities regulatoryauthorities in Canada, which are available onSEDAR under the issuer profile of Osisko atwww.sedar.com. Readers are urged to read thesematerials and should not place undue reliance onany forward‐looking statement and informationcontained in this Presentation. Except as requiredby law, Osisko assume no obligation to update theforward‐looking statements of beliefs, opinions,projections, or other factors, should they change,except as required by law. Unless otherwise noted,this Presentation has been prepared based oninformation available as of March 31, 2018.References in this Presentation to Osisko includeOsisko Mining Inc. and its subsidiaries.

CAUTIONARY STATEMENTS REGARDING TECHNICAL INFORMATION

31. See Appendix “A” for full disclosure on Mineral Resources.

MINERAL RESOURCES

This Presentation contains information regarding mineral resources estimated at the projects of the companies referenced herein. Mineralresources are not mineral reserves and do not have demonstrated economic viability. The estimate of mineral resources may bematerially affected by environmental, permitting, legal, title, socio-political, marketing or other relevant issues. In particular, the quantityand grade of reported inferred mineral resources in the estimates referenced in this Presentation are uncertain in nature and there isinsufficient exploration to define these inferred mineral resources as an indicated or measured mineral resource in all cases. It isuncertain in all cases whether further exploration will result in upgrading the inferred mineral resources to an indicated or measuredmineral resource category.

For details regarding the key assumptions, parameters and methods used to estimate the mineral resources presented in respect of theWindfall Lake gold project, please see the "Technical Report for the Windfall Lake Gold Project, Québec" dated April 17, 2014 (effectivedate March 3, 2014) filed on SEDAR under the issuer profile of Eagle Hill Exploration Corporation at www.sedar.com. Please note thatthe Windfall Lake PEA (as defined below) is based on a mineral resource estimate with an effective date of November 13, 2014.

For details regarding the key assumptions, parameters and methods used to estimate the mineral resources presented in respect of theOsborne-Bell Deposit, Quévillon Property, please see the “NI 43-101 Technical Report and Mineral Resource Estimate – Osborne-BellDeposit, Quévillon Property” dated April 23, 2018 (effective date March 2, 2018) filed on SEDAR under the issuer profile of Osisko atwww.sedar.com.

For details regarding the key assumptions, parameters and methods used to estimate the mineral resources presented in respect of theGolden Bear project, please see the "Technical Report for the Golden Bear Project, Ontario" dated March 3, 2014 (effective December30, 2013) filed on SEDAR under the issuer profile of Northern Gold Mining Inc. at www.sedar.com.

For details regarding the key assumptions, parameters and methods used to estimate the mineral resources presented in respect of theMarban project, please see the "Details regarding Technical Report for the Marban project – Marban block property, Ontario" datedAugust 15, 2013 (effective date June 1, 2013) filed on SEDAR under the issuer profile of NioGold at www.sedar.com.

PRELIMINARY ECONOMIC ASSESSMENT

The preliminary economic assessment of the Windfall Lake gold project (the "Windfall Lake PEA") is preliminary in nature and includesinferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them thatwould enable them to be categorized as mineral reserves, and there is no certainty that the Windfall Lake PEA will be realized.

QUALIFIED PERSON

The scientific and technical information contained in this Presentation has been reviewed and approved by Robert Wares, P.Geo. andExecutive Vice President Exploration and Resource Development of Osisko, a "qualified person" within the meaning of NationalInstrument 43-101 – Standards for Disclosure of Mineral Projects.

WINDFALL DEPOSIT APRIL 2019 AFTER +700,000 METRES: OPEN AT DEPTH AND GROWING

4

Composite Longitudinal section

Composite Longitudinal section

-400m

0m

-800m

-1200m

TRIPLE 8DISCOVERY

open in all directions

CurrentPlanned

Ramp

Caribou Zone

Wolf Zone

Underdog Zone

Zone 27

Crustiform vein

Lynx 1 Zone

Lynx 2 Zone

Lynx 4 Zone

Lynx 5 Zone

Lynx 6 Zone Bobcat Zone

Pierce points

Lynx 3 Zone

Underdog

Corridor

OPEN

INCREASE IN GRADE – INCREASE IN TONNES – INCREASE IN OUNCES

5

WINDFALL – UPDATED LYNX ZONE MINERAL RESOURCE

WINDFALL MINERAL RESOURCE ESTIMATE WITH LYNX UPDATE

WINDFALL AND LYNX DEPOSITSINTRUSIVE RELATED MINERALIZATION

6

SW Extension: up plunge extensions of mineralized corridors NE Extension: potential for new discoveries Near Deposit: northern contact, Bank Fault plus extensions and new zones in known corridors

Intrusive Breccia Target: NE Extension of Intrusive CenterZ27 Caribou

Mallard

F17 F51

Wolf

Target : SW Extension

Bank Fault

35o

Volcanic rocks

N60E

1000 m0.0 500

Red Dog dike

Surface Projection of the N60E - 35o NE plunging composite intrusive center

Target: Bank Fault

5 Km

ZONE 27 BULK SAMPLE

7

Plan view

CurrentPlanned Bulk and access

Ramp

ZONE 27 BULK SAMPLE

8

ZONE 27 BULK SAMPLE

9

First gold bar poured from a portion of the Zone 27 gravity concentrate

10

ZONE 27 BULK SAMPLE

PORTAL

ZONE 27 BULK SAMPLE

LYNX BULK SAMPLEZONE 27

LYNX

PEA Highlights

11.1. Based on the Q1/2018 consolidated financial statements. Some investments may differ from fair market value based on the IFRS accounting treatment.

Base CaseGold price US$1,300/oz, Silver price US$17.00/oz, Exchange rate C$1.00 = US$0.78, 5% discount rate

IRR after taxes and mining duties 32.7%NPV after taxes and mining duties C$413.2 million

Pre-Production Construction costs (including C$51.8 M contingency) C$397.3 millionPeak-year payable production 248,000 oz (year 1)Average LOM payable production 218,000 oz

Net gold payable recovery 92.4%Average diluted gold grade 6.7 g/t Au

Life of mine (LOM) 8.1 years

Total mineralized material mined 8,914,000 tonnes

Contained gold in mined resource 1,915,000 oz

Payable gold LOM 1,769,000 oz

Payable silver LOM 557,000 oz

All-in Sustaining Costs net of by-product credits and royalties over LOM US$704.00/oz

Estimated All-in cost (CAPEX plus OPEX) US$879.00/oz

Total unit operating cost C$126.47/ tonne milled

Gross revenue C$2.96 billion

Operating cash flow C$1.12 billion

Mine start-up/Full production Q2 2022/Q3 2022

NPV before taxes and mining duties C$625.4 million

IRR before taxes and mining duties 39.7%

TRIPLE 8 DISCOVERY

12

Major Canadian Archean Gold Deposits – Vertical ExtentWindfall Remains Open At Depth - Strong Potential to Grow

13

• Current depth of 2800m

• Min mining width 2m

• 209,000 oz Au (2017)

• Current depth of 2000m

• Min mining width 2m

• 194,000 oz Au (2017)

• Current depth of 3100m

• Min mining width 5m

• 349,000 oz Au (2017)

• Current depth of 1200m

• Min width 3.5m

• 248,000 oz Au (Y1 PEA)

Triple 8

AN EMERGING MINING DISTRICTDistrict-Scale: Over 3500 km² Property Position

14

Cadillac – Malartic -Val-d’Or Camp~70 Moz AuProduction

Timmins Camp~70 Moz AuProduction

Urban Barry Quévillon

Val-d'OrCanadian Malartic

1,688,000 oz @ 0.99 g/t Au (M)

7,344,000 oz @ 1.16 g/t Au (Ind)

GARRISON

Marban

Windfall754,000 oz @ 8.19 g/t Au (Ind)

2,364,000 oz @ 7.36 g/t Au (Inf)

N

0 25km

0 20km

0 20km

Bell Creek Hoyle

Pond

W. Timmins

Hollinger-McIntyre

Dome

Black Fox

Holloway & Holt Mine 35,000 Oz @ 3.83 g/t Au (M)

419,000 Oz @ 4.1 g/t Au (Ind)

LapaLaRonde

Goldex

Osisko Projects

Beaufor

DISTRICT-SCALE EXPLORATION OPPORTUNITY

Black Dog

FoxOsborne Bell510,000 oz @ 6.13 g/t Au (Inf)

BANK FAULT

Sigma-Lamaque

Doyon

KienaLac Herbin

PamourRoss

Aquarius

Clavos

Taylor

Sullivan

Paymaster

Hislop

BousquetMouska

Westwood

MoniqueEast

Malartic

SUMMARY AND CATALYSTS 2019

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• Well financed: approx. $200M in cash and equities

• Full focus on Windfall and the Windfall District

• 22 drills on site - Windfall deposit remains open at depth

• Positive resource update from Lynx, positive bulk results Zone 27

• Ramp progressing towards Lynx Zone for second bulk sample

• Excellent discovery potential on 3500 km² property

• Osborne Bell and regional exploration back to the forefront

• 2019 Catalysts: infill and expansion drill results, bulk sample

results, deep exploration, full Windfall resource update

• Feasibility in 2020