Collaborative approach to remediation at the Howard Mine Mill and Tailings Area Croston, Jonathan; Bains, Harbey; White, Jennifer; Sinnett, Geoff
SNC-Lavalin Inc. was contracted by the Crown Contaminated Sites Program (CCSP) of the BC Ministry of Forests, Lands, Natural Resource Operations and Rural Development to complete investigations and remediation at the former Howard Mine Mill and Tailings Area (Site) located south of Ymir, British Columbia. The Site included a mill and tailings deposit along the banks of the Salmo River. The mine wastes were determined to be acid generating, contain metal concentrations greater than soil standards protective of human and ecological health and were a source of contamination to the river. The mine wastes were located on Crown land; however, a small portion extended onto adjacent residential properties and contaminated a local drinking water well. CCSP prioritized the Site for remediation. Engagement with community, Indigenous Peoples and government agencies was an important part of the remedial planning process. It included meetings to seek input on the remedial plan and reclamation design. Through this engagement, consensus on the plan was achieved and the remedial work was approved by the BC Ministry of Environment and Climate Change Strategy. Remediation was completed in 2015 and included excavation and consolidation of mine waste into an approved hazardous waste facility covered with a bituminous geomembrane liner and growth medium. All disturbed areas were reclaimed and an erosion barrier/artificial floodplain with fish habitat was constructed on the east bank of the Salmo River. A new drinking water well was installed for the adjacent landowner. The site is currently undergoing long term monitoring to ensure the remedial works are performing as designed, as well as to measure natural attenuation of residual contamination in groundwater. Performance verification results indicate the remediation was successful in removing terrestrial risks to human and ecological receptors and reducing metals concentrations in groundwater, porewater and surface water across most of the Site.
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