Dewatered tailings facilities (thickened, paste, filtered) are generally considered safer alternatives to conventional tailings disposal, primarily due to the lower amounts of water stored as a pond or interstitially within the tailings mass. While it is acknowledged that a risk-based approach to TSF design should always be followed, the pressure to deliver projects quickly and often within limited budgets creates a tendency to rely on standards-based design criteria which may not always be directly applicable to dewatered tailings facilities.
Key design criteria commonly adopted from conventional TSF design are driven by the Population at Risk (PAR) and Dam Failure Consequence, slope stability Factors of Safety (FOS), Stormwater storage and Earthquake Loading. For dewatered tailings facilities it is important for stakeholders to recognise that prescriptive design elements, typically adopted from conventional TSFs, may not represent the most critical sources of risk, and therefore selection of design criteria should be case-specific.
There is arguably a void in international guidelines with respect to incorporating a design flowchart to streamline the design of dewatered tailings facilities. This paper discusses current practice for evaluating key TSF design criteria, taking as a base leading guidelines such as MAC (2019), ANCOLD (2012) and CDA (2007, 2014), and relates this to the context of dewatered tailings facilities. It identifies important elements to consider, issues likely to be encountered and areas of improvement, and provides a basis for continuing research and discussion.
