Slide 1: Reviving Historic Mining Camps in North America
JULY 2025 REVIVING HISTORIC MINING CAMPS IN NORTH AMERICA INVESTOR PRESENTATION ODV NYSE TSXV | osiskodev.com
Slide 2: Cautionary Statements
CAUTIONARY STATEMENTS CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING INFORMATION government, capital market conditions and the Company's ability to access capital on terms acceptable to the Company for the contemplated exploration and development at the Company's properties; the ability to continue
Slide 3: Cautionary Statements
CAUTIONARY STATEMENTS CAUTION REGARDING MINERAL RESOURCE ESTIMATES www.osiskodev.com. This Presentation uses the terms measured, indicated and inferred mineral resources as a relative measure of the level of confidence in the QUALIFIED PERSONS mineral resource estimate. Readers are cautioned that mi
Slide 4: Investment Highlights
INVESTMENT HIGHLIGHTS Building Toward Becoming a Premier North American Mid-tier Gold Mining Company ADVANCING SHOVEL READY CARIBOO GOLD PROJECT IN CANADA Limited universe of permitted development stage gold assets of scale in Tier 1 jurisdictions1 FOCUS ON SCALABLE ASSETS WITH DISTRICT SCALE POTENT
Slide 5: Mining Friendly Jurisdictions
MINING FRIENDLY JURISDICTIONS Brownfield properties with existing accessible infrastructure and meaningful exploration upside BC, Canada Utah, USA CARIBOO GOLD PROJECT 100% ownership TINTIC PROJECT 100% ownership EA Certificate (granted Oct 23) Trixie MRE (completed Mar 24) Permits (granted Q4 24) S
Slide 6: Executing on Vision & Strategy
EXECUTING ON VISION & STRATEGY Junior and Intermediate Gold Producers CAD$ $16B Billion log scale $15B $10B $5.9B $5B $4.0B Market Capitalization1 $2.4B $2B $2.6B Scarcity of Permitted Assets Cariboo is one of the few fully-permitted projects in a limited universe of developers with $1B gold assets
Slide 7: US$450 Million Appian Project Financing
US$450 MILLION APPIAN PROJECT FINANCING1 US$100 million Initial Draw US$350 million Subsequent Draw Conditions: Unconditional, fully drawn on close (July 21, Conditions: Final investment decision subject to certain 2025) customary project milestones and conditions precedent Term: 3 years (July
Slide 8: Capital Structure Snapshot
CAPITAL STRUCTURE SNAPSHOT Osisko Development Corp.1,2 Shareholder Ownership Current Share Price (closing price on July 25, 2025) C$3.23 /share 40% Basic Shares Outstanding 138.0 million Institutional Investors Options, DSUs, and RSUs 8.6 million 24% OR Royalties Warrants3 78.1 million Fully Diluted
Slide 9: Cariboo Gold Project
Video camera outline Watch Video CARIBOO GOLD PROJECT British Columbia, Canada 100% Ownership Double Tap Gesture with solid fill ODV NYSE TSXV 9 Virtual Tour osiskodev.com
Slide 10: Cariboo Gold Project: Asset Snapshot
CARIBOO GOLD PROJECT: ASSET SNAPSHOT Developing a mining camp in the under-explored Cariboo gold belt LOCATION / OWNERSHIP MINE TYPE METALS STAGE LAND PACKAGE Mosquito Wells 100% ODV BC, Canada Underground Gold Permits (Nov-24) >185,000 ha FS (Apr-25) Shaft Island Valley Barkerville Mountain NE Cow
Slide 11: 2025 Optimized Feasibility Study Highlights
2025 OPTIMIZED FEASIBILITY STUDY HIGHLIGHTS All $ figures in CAD, unless otherwise noted (USDCAD 1.35 base case) 190 KOZ / YEAR LOM AVG 10 YEAR MINE LIFE H2 2027 FIRST GOLD 202 koz/yr in the first 5 years Based on current reserves only 2028 first full year of production US $1,157/OZ AISC* $881M INIT
Slide 12: Bulk Sample and Underground Development Progress
BULK SAMPLE AND UNDERGROUND DEVELOPMENT PROGRESS Underground development 100% complete to access target area; results expected in Q3 2025 Shaft › Objective of the bulk sample is to advance underground development into Valley the ore body and extract up to 10,000 Mosquito Cow tonnes of mineralized ma
Slide 13: Lowhee Underground 2025
LOWHEE UNDERGROUND 2025 ODV NYSE TSXV 13 osiskodev.com
Slide 14: Project Location & Regional Infrastructure
PROJECT LOCATION & REGIONAL INFRASTRUCTURE Insights Large land package: total mineral tenure >185,000 hectares Brownfield site with year-round access, infrastructure and work force Grid power: allocated 22 MW from BC Hydro power at 6.7¢ per kWh — 69kV 70km transmission line to be constructed
Slide 15: Cariboo Project Permitting: Successfully Completed
CARIBOO PROJECT PERMITTING: SUCCESSFULLY COMPLETED BC Mines Act permits granted on Nov 20, 2024 — main permits for project construction & operation 2020 2021 2022 2023 2024 H1 H2 H1 H2 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 ENVIRONMENTAL ASSESSMENT Early Engagement Detailed Project Description Submissi
Slide 16: Outlook and Indicative Timeline
OUTLOOK AND INDICATIVE TIMELINE 9 months 12 months 12 months Project Financing / Final Investment Decision (FID) Detailed Engineering / Procurement Underground Development Construction Ramp up & First Gold Indicative timeline contingent on securing of project financing and a positive final investmen
Slide 17: 2025 Feasibility Production Profile
2025 FEASIBILITY PRODUCTION PROFILE Production profile based on current 2.07 Moz of Probable Reserves1 only Gold Production & Head Grade 190 KOZ/YR 202 KOZ/YR Gold Payable Production (koz) Head Grade (g/t Au) LOM average2 First 5 years average2 Significant upside potential from resource conversion a
Slide 18: Top Canadian Gold Mines/Projects
TOP CANADIAN GOLD MINES/PROJECTS Annual Gold Production (koz Au) 672 656 Cariboo is a scalable asset Underground Based on 2025 FS projections, Cariboo is already Open pit among the top underground gold assets in Canada, with significant upside potential 505 453 438 379 365 324 332 306 307 279 284 28
Slide 19: Global Gold Cost Curve Positioning
GLOBAL GOLD COST CURVE POSITIONING 2024 Global Total Cash Cost Curve (US$/oz) $3,500 $3,000 $2,500 Cariboo is $2,000 Cariboo Cariboo $947/oz ($947) Timmins ($1,700) positioned in the $1,500 LaRonde ($945) Porcupine ($1,097) Musselwhite ($1,045) Eleonore ($1,339) lower half of the Macassa ($748) $1,0
Slide 20: Capital Cost Breakdown
CAPITAL COST BREAKDOWN Capital costs ($ million) Initial Sustaining Total LOM Insights Underground mine 313 397 710 ~US$652 million upfront capex1 Water & waste management 98 24 123 Process plant and related infrastructure designed to accommodate potential future Power & electrical 19 — 19 throu
Slide 21: Robust Project Economics
ROBUST PROJECT ECONOMICS Base Case Spot Case after-tax, C$ US$2,400 Gold | 1.35 FX US$3,300 Gold | 1.40 FX Net Present Value (NPV5%) $943 mm $2,066 mm Internal Rate of Return (IRR) 22.1% 38.0% Payback, from first production 2.8 yrs 1.6 yrs Avg. Annual FCF* (LOM) $158 mm/yr $314 mm/yr Avg. Annual FCF
Slide 22: Mine Design Summary
MINE DESIGN SUMMARY Insights Access via two ramps from Cow and Valley Portals >1.2 km of access into Lowhee zone already completed as part of ongoing bulk sample program Maximum vertical depth ~650 meters Mining split into 3 distinct areas: Cariboo North, South, and Deep Bulk tonnage long-
Slide 23: Proposed Conceptual Mine Site Layout
PROPOSED CONCEPTUAL MINE SITE LAYOUT Insights Single processing facility at the Mine Site Complex Primary & secondary crushing underground and conveyed to the surface ore sorter Gravity and flotation processing circuits produce two gold concentrates Comminution circuit already purchased Pr
Slide 24: Mineralization Favorable to Ore Sorting
MINERALIZATION FAVORABLE TO ORE SORTING Ore sorting removes marginal material and generates an NPAG waste product at a low opex of C$1-2 per tonne Insights Pyrite hosted in quartz veins High Density 481 vein corridors with 2-meter minimum width Material (~5 g/cm3) Gold uniquely pyrite hosted wit
Slide 25: Processing Flowsheet
PROCESSING FLOWSHEET Gravity circuit to Totals may not add up due to rounding recover 46% of gold Crush/screen Sort Grind 2025 FS Addition Gravity / Flotation Dore (gravity) & Flotation Concentrate LOM recovery 92.6% Source: Refer to the 2025 Cariboo FS for the assumptions, qualifications an
Slide 26: Key Processing Elements
KEY PROCESSING ELEMENTS Process Overview Insights Crushed material is screened, with fines 1) Crushing & – Underground primary & secondary jaw crushers bypassing the tertiary crusher and reporting Screening – Screen at surface to separate size fractions for sorting directly to the mill feed bin
Slide 27: Cariboo Resource Conversion Potential
CARIBOO RESOURCE CONVERSION POTENTIAL Plan & Isometric View – North Shaft Zone Reserve Stopes Plan View Resource Stopes Planned Development Pink zones represent Reserve stopes Reserves include a total of 2.07 Moz1 3D View An additional 1.61 Moz contained within M&I resources and 1.86 Moz within Infe
Slide 28: Cariboo Exploration Potential at Depth
CARIBOO EXPLORATION POTENTIAL AT DEPTH LONG SECTION: LOOKING NORTHEAST EXISTING RESERVES & RESOURCES POTENTIAL VEIN CORRIDOR EXTENSIONS Conceptual Deposit Model 500 m 1 km OPEN 4.4 km strike OPEN 2.07 Moz Au at 3.62 g/t Au in Probable Reserves1 >500 m additional depth potential of known vein cor
Slide 29: A Potential Generational District
A POTENTIAL GENERATIONAL DISTRICT Long Section of Selected Canadian Operating Underground Mines vs. Cariboo Gold OSISKO DEVELOPMENT ALAMOS GOLD AGNICO EAGLE AGNICO EAGLE Cariboo Deposit1 Young-Davidson2 Goldex3,4 LaRonde Zone 53,5 Head Grade (Au) 3.62 g/t 2.08 g/t 1.55 g/t 3.62 g/t Gold Production 1
Slide 30: Immediate Exploration Upside at Cariboo
IMMEDIATE EXPLORATION UPSIDE AT CARIBOO 14 km trend from Mosquito Creek to Proserpine has exploration potential down to 1500m depth The sandstone unit hosting the CGP mineral resources was mapped and modelled and is believed to be continuous along the entire 14 km trend Cariboo Deep Assay highli
Slide 31: Developing a Mining Camp
DEVELOPING A MINING CAMP Cariboo hosts two main trends over 83 km in combined strike length District-scale exploration upside in under-explored Cariboo Gold Belt High degree of confidence in geological model with anomalous gold values >2.0 g/t Au in ~80% of drill holes >185,000 ha property wit
Slide 32: Tintic Project
TINTIC PROJECT Utah, USA 100% Ownership Double Tap Gesture with solid fill ODV NYSE TSXV 32 Virtual Tour osiskodev.com
Slide 33: Tintic Project: Asset Snapshot
TINTIC PROJECT: ASSET SNAPSHOT Highly Productive Historical Mining District LOCATION / OWNERSHIP MINE TYPE METALS STAGE LAND PACKAGE 100% ODV Utah, USA Underground Gold, Silver Trixie MRE >20,500 acres of (Q1 2024) Cu, Pb, Zn largely patented claims1 North Lily Located 95 km south of Salt Lake Cit
Slide 34: Trixie Initial Mineral Resource Estimate
TRIXIE INITIAL MINERAL RESOURCE ESTIMATE ("MRE")1 RESOURCE TONNES METAL GRADE CONTAINED METAL CUT-OFF GRADE Resources (koz) Grade (g/t Au) CATEGORY (000’s) VARIATION (g/t Au) (g/t Ag) (000’s oz Au) (000’s oz Ag) 27.6 MEASURED 120 27.36 61.73 105 238 24.0 19.1 M&I RESOURCES INDICATED 125 11.17 59.89
Slide 35: Trixie UG Ramp Development: 100% Complete
TRIXIE UG RAMP DEVELOPMENT: 100% COMPLETE RAMP DEVELOPMENT: ~1,390 M (4,550 ft.) 3 Historic Mineralized Zones Open at Depth and Strike Complete as of September 2023 756 ORE SHOOT 610 ORE SHOOT SOUTH SURVEY VEIN Enables bulk extraction at higher tonnage by providing Developed over 900 ft. (275
Slide 36: Trixie Exploration Potential
TRIXIE EXPLORATION POTENTIAL 2024 Trixie MRE represents a small footprint of the overall underground potential SOUTH NORTH Trixie MRE 2024 TRIXIE MRE1 440 meter strike length 60 meter width Empire State 195 meter depth building for scale (~4 football fields) Looking East 1. Refer to the full t
Slide 37: Drilling and Chip Sampling Highlights
DRILLING AND CHIP SAMPLING HIGHLIGHTS Completed a total of 6,028 m (19,776 ft) of Trixie exploration and delineation drilling in 2023 In 2023, the Company completed a total of 6,028 m Select Chip Sampling Select Drilling (19,776 ft) of underground drilling in 73 diamond drill HOLE ID WIDTH GRADE (
Slide 38: East Tintic Regional Exploration Potential
EAST TINTIC REGIONAL EXPLORATION POTENTIAL Highly prospective 5 km long corridor with 23 historic mines, extensive legacy datasets High-Sulphidation Epithermal Au-Ag Epithermal vein / breccia systems hosted primarily within the basal Tintic Quartzite host rock, found at the Trixie, Eureka Standard a
Slide 39: San Antonio Project
SAN ANTONIO PROJECT Sonora, Mexico 100% Ownership ODV NYSE TSXV 39 osiskodev.com
Slide 40: San Antonio Project: Asset Snapshot
SAN ANTONIO PROJECT: ASSET SNAPSHOT Asset Highlights Sonora Located 160 km from airport and towns of Hermosillo and Obregon in mining-friendly Sonora Constructed a heap leach pad and a carbon in column plant at the end of 2021 to process stockpiled mineralized material − 1.1 Mt stockpile grading
Slide 41: Appendix
APPENDIX ODV NYSE TSXV 41 osiskodev.com
Slide 42: Experienced Leadership Team
EXPERIENCED LEADERSHIP TEAM SEAN ROOSEN, CHAIR & CEO DAVID ROULEAU, VICE PRESIDENT, PROJECT DEVELOPMENT BOARD OF DIRECTORS • Founding member of Osisko Mining Corporation (2003-2014) • Seasoned executive with +35 years of operational and management • Responsible for developing the strategic plan for
Slide 43: Responsible Mine Development
RESPONSIBLE MINE DEVELOPMENT Committed to responsible mining practices, strong relationships, and mutual support with all partners ENVIRONMENT INDIGENOUS NATIONS ▪ Osisko Development constructed two water treatment ▪ Positive relationship with Lhtako Dené Nation since 2015. plants to treat contact w
Slide 44: Cariboo 2025 Feasibility Study Metrics
CARIBOO 2025 FEASIBILITY STUDY METRICS Cariboo Gold 2025 FS – Project Operating and Financial Metrics Cariboo Gold 2025 FS – Operating Costs Assumptions units 2025 FS Metric Total LOM Unit Cost Unit Cost Split Gold price US$/oz 2,400 ($ mm) ($/t mined) (US$/oz) (%) Exchange rate USDCAD 1.35 Mining 1
Slide 45: Cariboo Select High Grade Drill Results
CARIBOO SELECT HIGH GRADE DRILL RESULTS High-grade intercepts are consistently present throughout the entire deposit >50 g/t Au 25 – 50 g/t Au 15 – 25 g/t Au IM-19-013 BM-19-105 5 – 15 g/t Au 19.34 g/t over 20.66 g/t over IM-21-024 17.9 m4 12.8 m13 35.25 g/t over 346 gxm BGM-16-451 264 gxm IM-17-151
Slide 46: Cariboo Mineral Reserves & Resources
CARIBOO MINERAL RESERVES & RESOURCES (Measured and Indicated Resources are exclusive of Mineral Reserves) Mineral R&R Probable Reserves Measured Resources Indicated Resources Inferred Resources Tonnes Grade Ounces Tonnes Grade Ounces Tonnes Grade Ounces Tonnes Grade Ounces Deposit (000’s) (g/t Au) (
Slide 47: San Antonio Mineral Resources
SAN ANTONIO MINERAL RESOURCES TONNES GRADE (g/t) CONTAINED METAL DEPOSIT CATEGORY (Mt) SILVER GOLD SILVER (Moz) GOLD (koz) Indicated 3.9 2.5 1.22 0.31 153 CALIFORNIA Inferred 1.6 3.3 1.10 0.17 58 Indicated 5.7 2.5 1.44 0.46 262 GOLFO DE ORO Inferred 6.4 2.5 1.24 0.52 254 Indicated – – – – – HIGH LIF
Slide 48: 2024 Trixie Mineral Resources Estimate
2024 TRIXIE MINERAL RESOURCES ESTIMATE GRADE CONTAINED GRADE CONTAINED DOMAIN CATEGORY TONNES (AU G/T) GOLD (OZ) (AG G/T) SILVER (OZ) Measured 22,678 106.27 77,484 115.99 84,572 Indicated 11,939 23.19 8,902 51.07 19,602 T2 M+I 34,617 77.62 86,387 93.60 104,173 Inferred 1,996 9.82 630 61.38 3,938 Mea
Slide 49: Investor Relations Contact
PHILIP RABENOK, VICE PRESIDENT, INVESTOR RELATIONS prabenok@osiskodev.com | +1 (437) 423 3644 ODV NYSE TSXV | osiskodev.com