+ Tailings Stored: 40 Mt
+ PAG Waste Rock Stored: 160 Mt + Max Dam Height: + North Dam: 97 m + South Dam: 50 m + East Saddle Dam: 10 m
South Dam
Staging
Sequence Includes:
+ Dewatering (5 m)
+ Road construction
+ Foundation preparation (excavate to bedrock)
+ Dam construction
+ Liner installation
+ Tailings and reclaim water pumping system installation
+ TMSF Commissioning
Liner Subgrade Preparation and Subgrade Approval
Placement (GCL) Extrusion Welding
+ Containment of shallow seepage to the east and west of the facility expected
+ Potential for intermediate and deep seepage at low rates-to be field verified against existing predictive GW model.
+ Monitoring to be located as close as possible to allow early detection
+ Monitoring to include:
+ monitoring wells
+ surface seepage monitoring
+ surface water quality monitoring
+ Management: Trigger Response Plan and Adaptive Management Plan
+ PAG waste rock will initially be deposited along the west shore of the TMSF using mine fleet haul trucks
+ Autonomous dozers will spread PAG waste rock into the TMSF open water until PAG waste rock encompassing the entire northern portion of the TMSF has been developed
+ Tailings will be deposited from a single point discharge location at the southern end of the facility in Year 1
+ From Year 2 onwards, tailings will be discharged from the southern PAG waste rock bench
+ Prioritize safety for entirety of facility existence
+ Align with Tahltan Sustainability Requirements
+ Long term monitoring and compliance with TCG guidance
Note: Section is vertically exaggerated 5:1
+ PAG material: saturated with 1 m water cover
• PAG material and Closure Cover: targeted material placement provides extra layer of protection behind dams
• Tailings: bound by additional rock material between dams
+ Closure cover: adjacent to north and south dams
+ Small access road: to be maintained along western shore
Mining Association of Canada – Tailings Guide, Version 3.2
+ Failure Pathways and Control Measures:
+ Overtopping Operation Spillways
+ Internal Erosion Coarse Rockfill Dam
+ Foundation Failure Strip foundation to Bedrock
+ Operational/Design Review, Monitoring, and Safety Practices:
+ Engineer of Record (EOR)
+ 3rd Party Independent Review
+ Independent Tailings Review Board (ITRB)
+ Dam Safety Reviews (every 5 years)
+ TSF Qualified Person
Aligned with: Health, Safety and Reclamation Code for Mines in BC, April 2024
+ Operation, Maintenance and Surveillance (OMS) Manual – QPOs and TARPs
+ Annual Facility Performance Report (March 31st each year)
