Supporting continued mine production since 1969
Since 1969, KCB has been involved in the design, construction and decommission planning of tailings storage facilities at the Highland Valley Copper (HVC) mine – a copper-molybdenum mining complex located near Logan Lake, 50 km southwest of Kamloops, British Columbia. The HVC mine, owned by Teck Resources, is one of the world’s largest copper mining and milling operations.
Challenges
- Design for annual tailings dam raises to match mine production
- L-L starter dam constructed over lacustrine deposits up to 12 m thick (in the 1970s)
- Understanding and mitigating impact on ground-water conditions
- Understanding, designing for and establishing preventative measures for potential failure modes
- Continued development and expansion of mining resource and management facilities while managing impacts and risks to natural environment
- Tailings management is an integrated system involving several groups including mine operations, mill operations, environment, dam safety team, engineering group and contractors
Solutions
- Adopted centreline tailings dam design for two dams with impervious glacial till core
- L-L Dam constructed from hydraulically-placed cycloned sand; H-H Dam constructed from earth and rockfill
- L-L Dam design includes drainage features to limit seepage losses to the foundation and maintain low phreatic level in downstream shell
- Planned, installed and monitored groundwater monitoring wells and instrumentation
- Failure Modes Effects Analysis to define potential risks and triggers to failure
- Documented preventative controls for each trigger and implemented Observational Method to compare design predictions to observed behaviour and incorporate back into design and proactive decision making
- Developed conceptual and numerical groundwater models to support permitting
- Integrated management systems developed with input from other groups and based on a “plan-do-check-act” system focused on continual improvement
Successes
- Each dam is designed and built to suit availability of borrow materials at each site; combined, they retain a tailings impoundment with storage capacity of approx. 1.3 billion tonnes
- Both dams meet permit requirements related to downstream water quality and designs have been adaptive to evolving hydrogeological understanding and regulatory/stakeholder expectations
- State of practice dam surveillance program integrated with operations, design, mine planning and site wide risk management systems
- Presented findings to First Nations, regulatory agencies and other stakeholders as part of permit applications
- Tailings management, dam safety, surveillance, emergency response and short to long-term planning are integrated across multi-disciplinary teams and consistent with side wide practices.
