The Yankee Girl site is an abandoned tailings area located on the shore of a river in the small community of Ymir, British Columbia, Canada. Tailings periodically eroded into the river and oxidation resulted in the release of contaminants, including cadmium, lead and zinc, into a high-value fish habitat. After extensive consultation, the BC Crown Contaminated Sites Branch and the local office of SNC-Lavalin arrived at a remediation objective that would turn the area into a park-like setting for use by the local community.
In 2007, SRK was awarded a design-and-build project in partnership with Quantum Remediation, a well-respected BC contractor specialising in contaminated site remediation. SRK’s design centered around the relocation of low-lying tailings from the river floodplain into an engineered containment system constructed on an upper tailings bench.
During the relocation, lime was added to neutralise acidity and precipitate soluble contaminants. The engineered containment system included a bentonite-amended soil cover to minimise the infiltration of water. A passive treatment system, constructed using organic wastes from a nearby pulp mill, was incorporated to remove any residual contaminants from the underlying groundwater.
The design-build partnership provided an opportunity to create a number of construction efficiencies in the design while delivering a quality product. Innovative QA/QC methods were developed to control the addition of lime to the tailings and the mixing of bentonite with the lower layer of the soil cover.
The project incorporated several features selected by the local community, including an amphitheatre and parking area for concerts, natural topography and vegetation, and provision for a disk-golf course. The construction was completed on schedule and within budget, and transformed an unproductive and hazardous site into a high-value recreational area for the local community.
