This paper explores geotechnical aspects of closure as it relates to valley type tailings storage facilities (TSF). At closure differential settlement of the final tailings surface within a valley tailings storage facility can be problematic. As the tailings consolidate, a ‘dish’ is formed within the tailings storage basin, typically near the main embankment dam. The formation of a concave top surface has implications for closure of the facility as rainfall runoff can migrate through the TSF top surface cover into the deposited tailings. In addition, this may have implications with respect to the long term stability of the main embankment as factors of safety may be reduced as the pond moves towards the embankment. Investigation of a valley tailings storage in Northern Australia and subsequent consolidation analysis indicated that estimates of post closure tailings settlement for the proposed top surface cover were manageable with the likelihood of significant ponding on the TSF cover considered to be low.
Christopher Hogg (Fri,) studied this question.