Teck Resources Limited Class A · TSX:TECK.A
Teck Resources Limited Class A — Juneau Mining Forum Information Webinar 2026
26 slides from Teck Resources Limited Class A's conference presentation, Feb 24, 2026
Slide 1: Tulsequah Chief Mine Juneau Mining Forum Information Webinar
TULSEQUAH CHIEF MINE JUNEAU MINING FORUM INFORMATION WEBINAR Dr. Deborah Read, Site Manager February 24, 2026
Slide 2: About Teck Resources
ABOUT TECK RESOURCES Teck is a leading Canadian critical minerals company focused on responsibly providing metals essential for global development and the energy transition. 100+ years of history as a Canadian company headquartered in Vancouver, B.C. 6 total operations in Canada, the U.S., Chile and
Slide 3: About TRTFN
ABOUT TRTFN • Located in Atlin, BC - a remote community of approximately 400 people. • Territory covers over 40,000 km2 • Represent TRTFN Citizens on all matters that could affect Territory • TRTFN Lands Mining Division has been involved in the active planning for the reclamation of the mine since 2
Slide 4: Tulsequah Chief Site Location
TULSEQUAH CHIEF SITE LOCATION The mine is located approximately 100 km south of Atlin, British Columbia, on the Taaltsux̱éi Héen. The mine is approximately: • 10 km upstream of confluence of Taaltsux̱éi Héen (Tulsequah River) and T'aakú Héeni (Taku River) • 30 km from the US border • 50 km NE of Jun
Slide 5: Timeline of the Tulsequah Chief Mine
TIMELINE OF THE TULSEQUAH CHIEF MINE Teck voluntarily conducts Objective: Teck and TRTFN developing a final remediation plan for the site remediation planning. Redfern Remediation discussions purchase the with Teck, BC, and mine. TRTFN, including current efforts focused on long- Cominco term permane
Slide 6: Site Layout
SITE LAYOUT Upper and lower mine workings, airstrip, camp, lime sludge pit waste rock, WTP (not functional), lime sludge pit, exfiltration pond barge landing, barge camp, fuel storage 6
Slide 7: Mine Workings Cross Section
MINE WORKINGS CROSS SECTION ground surface 6500 Level Upper workings 6400 Level 5900 Level (blocked at 90m) tunnels Lower workings 5400 Level mined out cavity 5200 Level (dam at 390m) Current remediation concept - Secure all portals to prevent human entry - Plug 5200, 5400 to prevent acid mine drain
Slide 8: , Poe Blas
, Poe Blas ar, cant 5400 Level ie + Wasie Rock Ore Storage icv A SS -NORPAG Bedrock —2 at 7) hy Welty 4 ae H PAG, Bedrock Waste.Rock Fuel Storage Hazardous Wastes A onc 5200 Level & " ‘ * a J 3 Exfiltration Pond and Spillway
Slide 9: Progress Made During 2024 and 2025 Field Seasons
PROGRESS MADE DURING 2024 AND 2025 FIELD SEASONS Water Safe Underground Management Mined Rock Environment Waste Access (U/G) and Monitoring Maintain safe, Clean up and Install temporary Remove reliable access Secure assess existing sediment control Quantify waste some historic to site underground wa
Slide 10: Safe Access
SAFE ACCESS Challenging Site Access • Airstrip maintenance and weather station setup Historic camp not usable • Temporary accommodation setup Limited safe access to site components: • Construction of helipads at upper portals • Urgent maintenance on two bridge decks • Scaling of loose rock Footnote
Slide 11: Before After
Before After Teck Teck - Internal/Interno
Slide 12: Underground
UNDERGROUND 2024 and 2025 Drone Surveys: • Conducted in 5200, 5400, 5900, and 6400, and 6500 Levels. • 5200 Level dam observed retaining water but past design life—potential safety risk. • Data will inform engineering for safe access. Footnote if requ ired 12
Slide 13: Sludge depth estimated to be 45 cm
Sludge depth estimated to be 45 cm 13
Slide 14: 5200 L Portal Dam at 392m
5200 L Portal Dam at 392m IN FLIGHT | UPTIME || ASSIST) 341 SIS ||sPoRT X: 310m Y¥. 236m | Z: 235m D:3924m H: 355° Kd <1 (TP) prisceed < 100 >
Slide 15: Underground
UNDERGROUND 2025 Underground Stabilization Work: • 5400 Level: Debris cleared, timber replaced. • 5900 Level: Reinforced with timber and bolts. • 6400 Level: Loose rock removed. Footnote if requ ired 15
Slide 16: May 2025 August 2025
: 4 ; i q : a i is ¢ May 2025 August 2025 Teck Teck - Internal/Interno
Slide 17: Teck - Internal/Interno
17 Teck - Internal/Interno Teck
Slide 18: Water Management
WATER MANAGEMENT Clean and inspect existing temporary water treatment plant Assessed potential refurbishment requirements Footnote if requ ired 18
Slide 19: Water Treatment Plant (WTP)
WATER TREATMENT PLANT (WTP) Black mould remediation Equipment assessment Control systems assessment 19
Slide 20: Water Monitoring
WATER MONITORING Sampling: 2024: AEMP (Water quality, sediment, benthic invertebrates, slimy sculpin) 2025: Monthly water quality sampling at 36 valley locations. Sediment samples collected in June and September. TRTFN participated in 2024 and 2025 Footnote if requ ired 20
Slide 21: Water Quality
WATER QUALITY • Water from UG and waste rock dumps is acidic • High concentrations of Al, Cd, Cu, Fe, Zn • Elevated concentrations of As, Pb, SO4 Downstream Impact: 5400 • Elevated Metals: higher metal levels in water and sediments up to 3 km downstream, beyond that, conditions normalize. • Benthic
Slide 22: How Does the Mine Affect Salmon in the Taaltsuxéi Héen?
HOW DOES THE MINE AFFECT SALMON IN THE TAALTSUX̱ÉI HÉEN? . Salmon Impact: • High metal levels can affect survival and navigation. • Acidic water can harm insects & habitats for feeding/spawning. • Adult salmon migrating past the mine unlikely to accumulate metals. • Habitat use within 0-3 km would i
Slide 23: Environment
ENVIRONMENT Bat Monitoring: • Equipment installed at portals to detect bat roosting/hibernation. • Monitoring to continue to 2027 to inform planning for remediation of underground. Climate Change Studies • Focused on future temperature, rain, and snow trends. • Results to guide long-term engineering
Slide 24: 2026 Proposed Plans
2026 PROPOSED PLANS Water Safe Underground Management Mined Rock Environment Remediation Access (U/G) and Monitoring Planning Maintain safe, Assess options for Draft Quantify the Understand reliable access Secure mobile water Remediation geochemistry of aquatic risk to to site underground treatment
Slide 25: Next Steps
NEXT STEPS Teck and TRTFN will continue collaboration on remediation planning: • Plan 2026 field season • Review information from technical reports • Renew regulatory approvals • Advance community engagement efforts 25
Slide 26: Thank You
Teck THANK YOU
Teck Resources — Juneau Mining Forum Information Webinar 2026 on 6ix