Challenges with Conducting Tailings Dam Breach Assessments
Author: Alana Shewan, Anna Akkerman, Violeta Martin
Conference: 85th Annual Meeting of International Commission on Large Dams
Date: July 3-7, 2017
ABSTRACT
Following the recent tailings dam breaches at Mount Polley, Canada, and Samarco, Brazil, the mining industry and regulatory agencies worldwide increased the demand for tailings dam breach analyses and flood inundation mapping. The results of such studies are used to determine the hazard classification of a dam through the assessment of dam failure consequences, to support emergency preparedness and response planning, and to inform environmental assessments. Dam breach studies involve the selection of a dam failure mode and appropriate hydrologic conditions, the approximation of the breach size, the estimation of the volumes of released tailings and water, and the modelling and mapping of the runout pattern of released materials. There is considerable uncertainty in each step of the analysis, which combined with the lack of a standardized approach for completing such studies, necessitates that practitioners rely on experience and sound professional judgement to conduct the studies and assess the results. In this paper, we review some of our recent experiences with tailings dam breach assessments and discuss challenges encountered and lessons learned for various case studies, including selecting credible failure modes, selecting appropriate hydrologic parameters, determining the range of possible breach parameters, and estimating the volumes of released tailings.
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