Tailings Facility Expansion and Operation Plan "Overcoming Weak Foundation Challenges"

To accommodate an increased mine life, Seabee Mine required an expansion to their tailings storage capacity. This meant an increase in containment for their existing East Lake and Triangle Lake tailings management facilities (TMFs). Due to regulatory, operational, and space limitations, innovative solutions were necessary. Specifically for the East Lake TMF, staged construction of a waste rock containment dike directly over historically deposited tailings was required.   

A foundation characterization program was undertaken prior to completing the TMF expansion design. This characterization confirmed the presence of unconsolidated tailings zones with variable thickness overlying more competent ground. The impact of this variability was examined through rigorous sensitivity analysis in the initial design analysis of the structure; followed by construction of a full-scale test section within the existing facility footprint. Test section monitoring data was used to reassess and confirm the design analysis such that full-scale construction could commence. Stage 1 construction was completed in May 2016 with tailings placement immediately after in accordance with a detailed operations plan that includes a comprehensive tailings deposition plan and associated water balance.   

This paper presents an overview of the findings from the test section monitoring, details of the operations plan, and a discussion of Stage 1 operation during the summer of 2016. The information presented demonstrates how rigorous numerical analysis coupled with sound experiential judgement can be used to overcome challenging operational issues continuously faced by mining companies.