HB Mines Tailings Facility

Closure and Remediation Project

Background

• The HB Dam, located 6km south of Salmo, was initially constructed by Teck Cominco (Teck) to retain and store tailings from the nearby HB Mine, which Teck operated intermittently from 1955 to 1978.
• In 1998, the RDCK acquired the HB Mine Tailings Storage Facility and land adjacent to the Central (Salmo) Landfill to be used as attenuation and buffer area for the landfill. Decommissioning of the tailings dam took place between 2002 and 2005 and was partially funded by Teck.
• Since then, the RDCK has been engaged in regular monitoring, reporting and assessment of the Facility. This involves regular inspections, environmental monitoring, annual geotechnical reviews, annual reclamation reporting, annual updates to emergency and operations plans, detailed dam safety reviews and Reclamation Plan updates.
• In 2012, the earth dam nearly collapsed after heavy rains. A collapse would have had disastrous impacts on the nearby highway, downstream properties and the Salmo River, with clean-up costs estimated at up to $84 million. The RDCK declared a State of Local Emergency for the area and embarked on immediate repairs and intensive monitoring.
• In 2016, the Board approved moving forward with passive closure, as defined by the Canadian Dam Association, of the tailings facility which involves construction works to stabilize the dam and remediate the tailings area.
• SRK Consulting Inc. completed the closure and remediation design in August 2020, which formed the basis of a series of permit applications that would allow the closure works to proceed
• The project commenced on June 3, 2021 and was completed in September 2022.
• The Facility is now in the active care phase, anticipated to last 3 to 5 years, where increased monitoring and oversight is completed to assess the Dam’s performance compared to projections in the design.
• Once adequate monitoring has shown that the Facility is geotechnically, geochemically and environmentally stable, the RDCK can apply to reduce monitoring frequencies which will reduce long-term costs.