Oceanagold Corporation · TSX:OGC
Oceanagold — Technical Presentation (May 2026)
30 slides from Oceanagold's technical presentation, May 2026
Slide 1: Haile Site Visit
a) OCEANAGOLD Haile Site Visit May 2026 a
Slide 2: Cautionary Statements
Cautionary Statements Cautionary Note Regarding Forward-Looking Statements This presentation contains certain “forward-looking statements” and “forward-looking information” (collectively, “forward-looking statements”) within the meaning of applicable Canadian and United States securities laws which
Slide 3: A Track Record of Responsible Mining at Haile
A Track Record of Responsible Mining at Haile OceanaGold acquired Haile SEIS Record of Decision and Mine First development Romarco Minerals Operating Permit received to expand ore from Ledbetter surface footprint & build Horseshoe UG UG expected1 2015 2022 2029 2036+ Current mine life1 Reserve only
Slide 4: Recent Technical Report Highlights – Production Profile
Recent Technical Report Highlights – Production Profile Mine life extended to 2036, based on Life of Mine Production and AISC1 Profile ($/oz)2 Reserves only Avg. production of 210,000 oz Au per year Consistent production profile allows 300 $5,000 for more stable AISC1 profile over life 245 $4,500 Po
Slide 5: Continued Focus on Safety
Our goals: To be a world-class leader in safe Continued Focus on Safety production With a proactive approach to preventing injury To be a US site that people want to work at Total Recordable Injury Frequency Rate (“TRIFR”) In 2023 our focus was on (per 200,000 hours) improving incident reporting 3.0
Slide 6: Our Safety Programs at Work
Our Safety Programs at Work Behaviors that affect safe work OurSafe Departmental “Behaviors” and “Plays” driving safe outcomes for that department Behaviors Opinion Leaders made up of and nominated by the hourly workforce App-based Fatal Risk verifications Forwood Removing Fatal Risks by verifying C
Slide 7: A Trusted Local Partner
✓ ✓ Federal SC Department of Ongoing Permit Fully Permitted Environmental Services Modifications A Trusted • May 2018: Initiated SEIS • Dec 14, 2022: Mine operating • SCDES Minor Local Partner process for 404 major modification permit major modification received Modification: Method of Mining change
Slide 8: A Trusted Local Partner
A Trusted Local Partner ✓ Legacy • 2027 will mark 200 years of mining • 2025 South Carolina Impact: over 1,800 jobs and $717M economic impact • Life of Mine Impact: $9.3B by 2037 ✓ Community Support • $180k annual sponsorship and donation commitments • $250k 5-Year Commitment for initiation of Rural
Slide 9: An Engaged Workforce
An Engaged Workforce Significant decrease in employee turnover in the last 5 years Employee total turnover = 14.9% Complete culture shift including safety always & family Retention first, market benchmarked rewards, wellbeing program, and rewards increased communication, and driving positive mindset
Slide 10: Underground Mining Operations
Underground Mining Operations Production rates increasing under fully owner-operated crews 2023 2024 2025 Ore Mined kt 83 404 611 Horseshoe UG contractor demobilized Q4 2024 Ore Mined Grade g/t 5.29 5.32 3.67 Development meters 1,325 4,812 3,264 Successful transition to owner operated model in 2025
Slide 11: Horseshoe Underground
Horseshoe Underground Development well ahead of production stoping derisks the mine plan Optimization at Horseshoe Underground in 2025 included: Improved efficiencies through Short Interval Control and data integrity Focused decline development to debottleneck production levels Planning Management O
Slide 12: Underground Mining Production Schedule
Underground Mining Production Schedule Two additional underground ore sources come on-line by 2029 2.0 6.0 5.0 Combined 1.5 Au Grade (g/t) 4.0 Underground 1.0 3.0 Production Mt 2.0 Schedule1 0.5 1.0 0.0 0.0 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 Horseshoe Ore Palomino Ore Ledbet
Slide 13: Ledbetter Underground
Ledbetter Underground Ledbetter to be mined as an underground mine Open pit scenario required significant pre-strip at 9.4:1 Underground scenario provides: • Higher NPV Ledbetter Phase 4 Ledbetter Phase 3 • Earlier access to sustainable Open Pit ore production • Lower capital expenditures Ledbetter
Slide 14: Underground Capital Projects
Underground Capital Projects → Decline development began Q1 2026 Palomino → Surface high-voltage power early 2027 $135M1 → Ventilation shafts by end of 2027 → First ore 2028 → Surface high-voltage power end of 2027 → Commencement of LUG portal early 2028 Ledbetter → Incline from PUG mid 2028 $153M1
Slide 15: Surface Mining Open Pit Sequencing
Surface Mining Open Pit Sequencing Total Tonnes Mined by Area (Mt)1 40.0 30.0 20.0 10.0 - 2026 2027 2028 2029 2030 2031 2032 2033 Ledbetter Champion Total Ore Tonnes Mined by Area (Mt)1 6.0 Small 5.0 4.0 3.0 Haile Snake 2.0 1.0 - 2026 2027 2028 2029 2030 2031 2032 2033 Snake: Phase 3 Ledbetter: Phas
Slide 16: Fleet Maintenance
Fleet Maintenance Maintenance Transformation Plan driving significantly improved fleet availability Maintenance Transformation Plan embedding supervisor capability, Short Interval Controls and an optimized management operation system has led Primary Mining Fleet to uplift in availability and Mean Ti
Slide 17: Processing Physicals
Processing Physicals Debottlenecking and crusher improvement a key focus Processing Physicals 2022 2023 2024 2025 Gold Production koz 176 153 213 185 Processing Plant Mill Feed Mt 3.5 3.4 3.0 2.9 Throughput Improvements Mill Feed Grade g/t 1.90 1.72 2.59 2.32 Crushing Recovery % 82.1 81.3 86.2 86.3
Slide 18: Continuous Improvement Initiatives
Continuous Improvement Initiatives Embedding a Continuous Improvement mindset across the site Over $30M in Continuous Improvement (CI) value delivered in 2025 Robust CI project pipeline poised to deliver further cost savings in 2026 CI engagement results in value delivery, procurement savings, opera
Slide 19: Surface Capital Projects at Haile
Contact water pond excavation on track – drill and blast planning for Completion West PAG3 final cut expected: Liner placement commenced in Q3 2026 April Earthworks commenced as Surface Capital Metal planned Completion Projects at Haile Removal Plant Engineering and equipment expected: Q4 2026 selec
Slide 20: Development of PUG and LUG Drive Capital Cost Profile
Development of PUG and LUG Drive Capital Cost Profile Capital Cost Profile1 Growth projects include Palomino, 300 Ledbetter UG & Water Treatment 250 Sustaining projects include PCR 200 Maintenance, Equipment replacement and continued US$M infrastructure needs 150 100 Capitalized mining 2026-2028 dri
Slide 21: Mining and Processing Costs
Mining and Processing Costs1 LOM Surface Mining Cost LOM Underground Mining Cost LOM Processing Unit Cost Breakdown (%) Breakdown (%) Breakdown (%) LOM Cost: $6.68/t mined LOM Cost: $61.29/t mined LOM Cost: $23.28/t milled 18% 12% 24% 38% 10% 52% 13% 50% 3% 7% 4% 1% 5% 24% 8% 15% 3% 13% Personnel/Ex
Slide 22: Exploration Overview
Exploration Overview Multi-million ounce mine with further upside potential Mines & Prospects Strategic Only gold producer in under-explored OGC Tenements Position gold district Resource Areas Fourth largest operating gold Target Areas mine in the United States Continue exploration with focus on und
Slide 23: 2026 Exploration
2026 Exploration Targeting mine life extensions Proven & Probable Measured & Indicated Inferred 2026 Exploration 2026 Exploration Drill Mineral System Gold Reserves1 Gold Resources1 Gold Resources1 Guidance Metres 2.29 Moz 2.72 Moz 0.1 Moz $10M 34.6 km Epithermal Au Ledbetter | 35% 5,900 m Conversio
Slide 24: Geology Overview
Geology Overview Improved understanding of lithology, structures, alteration, and mineralization is unlocking new search space Increased focus on geochemistry and structural data to drive additional target opportunities 24
Slide 25: Case Study | Early-Stage Exploration at Clydesdale
Case Study | Early-Stage Exploration at Clydesdale Using adularia alteration to vector toward mineralization Current drilling confirms adularia is closely associated with gold-bearing zones in the target area Cross Section A – A’ Looking 052 +/- 150 m Cross Section A – A’ Looking 052 +/- 150m Ledbet
Slide 26: Appendix
4) OCEANAGOLD Appendix
Slide 27: Proven and Probable Reserves
Proven and Probable Reserves As at December 31, 2025 Proven Probable Proven & Probable Contained Contained Contained Tonnes (Mt) Au (g/t) Tonnes (Mt) Au (g/t) Tonnes (Mt) Au (g/t) Cut-off grade Gold Ozs (Moz) Ozs (Moz) Ozs (Moz) Horseshoe Underground 1.52 4.39 0.21 2.63 4.24 0.36 4.14 4.29 0.57 1.86
Slide 28: Measured, Indicated & Inferred Resources
Measured, Indicated & Inferred Resources As at December 31, 2025 Measured Indicated Measured & Indicated Inferred Tonnes Contained Tonnes Contained Tonnes Contained Tonnes Contained Au (g/t) Au (g/t) Au (g/t) Au (g/t) Cut-off grade Gold (Mt) Ozs (Moz) (Mt) Ozs (Moz) (Mt) Ozs (Moz) (Mt) Ozs (Moz) Hor
Slide 29: Technical Disclosure
Technical Disclosure Notes to Mineral Reserves and Mineral Resources Estimates All Mineral Reserves and Mineral Resources were estimated as of December 31, 2025 and have been prepared in accordance with NI 43-101. Mineral Reserves and Mineral Resources estimates are reported on a 100% basis. All ton
Slide 30: Investor Relations Contacts
BRIAN MARTIN SVP, Business Development & Investor Relations REBECCA HENARE 400 Burrard Street #1020 Vice President, Investor Vancouver, British Columbia Relations V6C 3B7 Canada +1 604 678 4123 VALERIE BURNS ir@oceanagold.com Manager, Investor Relations oceanagold.com