Accurately modeling a tailings storage facility (TSF) breach is complicated due to the magnitude of uncertainties associated with the modeling parameters. Currently, there are no industry technical standards for developing the embankment breach parameters during a tailings breach assessment (TBA), and the typically referenced equations used to estimate embankment breach parameters are, in most cases, empirical (DSO 1998) and largely based on past failures of water-retaining dams less than 30 m high—which is not particularly applicable to large TSFs or TSFs in general.
Because of the complexities of a TSF embankment breach study and the inherent subjectivity on how to consider this process, a simplified approach is typically employed by most practitioners. The framework of which is generally based on four pillars:
Pillar 1 à Definition of study objectives
Pillar 2 à Identification of credible failure modes
Pillar 3 à Estimate of volume of tailings released and apply embankment breach parameters
Pillar 4 à Estimate of downstream inundation extents
As every TSF is unique, employing a one-size-fits-all approach for each of the four pillars results in an inaccurate characterization, or biasness, of many TSFs, based on contradictive assumptions. To limit this bias, it is important to use a framework that seeks to manifest logical connections between the four tailings dam breach assessment pillars.
This presentation discusses the four main pillars of a tailings dam breach analysis (TDBA) and how they can be leveraged universally across all TDBAs.