BC Mine Closure Ecological Risk Assessment

Client: Teck Cominco Ltd., Kimberley Operations (for SNC-Lavalin Environment Inc.)

Azimuth staff led the development and implementation of a detailed ERA addressing post-closure contamination scenarios at a mine property. This complex ecological risk assessment (ERA) was conducted in a tiered fashion building on previous site investigations, which have ranged from routine surface water quality monitoring to characterizing site hydrogeology, to designing and testing cover systems for the tailings impoundments, waste rock piles and other areas with elevated contamination. Earlier tiers of the risk assessment addressed broad issues to identify the important ones; subsequent tiers focused on the key issues and refined risk predictions until the associated uncertainty was sufficiently low to make management decisions. The terrestrial component of the ERA used a combination of direct effects measurements (e.g., habitat assessment) and food chain modeling to characterize potential risks to plants and soil invertebrates, birds and mammals. The aquatic component of the ERA included a comprehensive benthic community study, a fish survey, and food chain modeling to assess potential risks to aquatic birds and mammals.

This is the first mine site undergoing closure under the joint jurisdictions of the Contaminated Sites Regulation and Mines Act. The project has posed unique challenges that have led to unique solutions. Throughout the risk assessment process, Azimuth has been directly involved in consultations with local stakeholders and regulators to ensure that appropriate feedback was incorporated into the ERA’s technical approach.