Weather hazards are a leading cause of tailings storage facility (TSF) failures, with weather‑triggered flow incidents increasing (Rana et al. 2021).
While spillways are a common means of providing TSF flood discharge capacity, many facilities are designed as ‘non-discharge’ systems which contain all inflows within the basin.
Designing non-discharge TSFs requires an understanding of the critical storm duration, yet guidance is inconsistent and practice often defaults to 24–72‑hour events with limited justification.
This paper presents a practical method for identifying the critical storm duration for non‑discharge TSFs using water-balance modelling in parallel with emergency response assumptions.
