Probability Distributions of Tailings Dam Breach Volumes by Failure Mode as Part of a Risk Screening-Level Tool

The mining industry is constrained by available qualified professionals to perform detailed risk assessments for tailings storage facilities. As such, a suite of simple spreadsheet models and guidance to support assessment of tailings dam risk using a combination of failure statistics and engineering judgment is being developed by the authors. The objective of this work is to complement expert-based quantitative or semi-quantitative risk assessment methods and accelerate the adoption of risk-informed decision making in all phases of tailings dam management. Designers and dam owners can apply this framework to improve consideration of risk in site selection and preliminary design; support rapid screening and prioritization of large portfolios of dams; inform expert-based assignments of failure mode probabilities; help assess the reasonableness of risk assessment results generated using more rigorous methods; and inform the range of dam breach analysis scenarios that should be conducted in consideration of the risk drivers. The current work, and focus of this paper, is estimating tailings release volume using a statistical approach to assign preliminary probability distributions of the release volume by failure mode. Guidance is provided for adjusting the baseline release volume distributions according to site conditions, such as impounded tailings volume, pond volume, liquefaction susceptibility, dam height, fill materials, and dam configuration.

Conference paper