Tailings dike seepage mitigation through adaptive tailings deposition sequencing

ABSTRACT: This paper presents the summary of a seepage remediation strategy put in place to mitigate the water seepage observed underneath a tailings retention dike at a mine site located in a permafrost environment in northern Canada. Effective seepage mitigation was achieved through adaptive tailings deposition sequencing. Following the first observations of seepage, field investigations and extensive numerical modelling were performed to understand its mechanism, establish appropriate mitigation options and quantify the efficiency of the mitigation strategy over time as the tailings storage facility was operated and sequentially raised. In addition, the seepage mechanism understanding gained was incorporated into a detailed Trigger Action Response Plan for the dike. This paper provides an overview of the evolution of the situation over the operational life of the structure, which is now nearing closure stage, and provides insights about the use of tailings deposition as a seepage mitigation tool.