Influence of the particle size distribution on the Critical State Properties of Mine Tailings

Arguably, critical state soil mechanics (CSSM) is now the preeminent methodology for understanding static liquefaction of mine tailings, having been used in the mining industry by the expert panels retained to investigate recent TSF failures. One of the key ingredients of the CSSM framework is the assessment of a critical state line, which separates contractive from dila-tive states. A critical state line is often defined by a linear relationship and two parameters, namely the altitude of the critical state line at 1 kPa (¿) and its slope (¿). In this study, we use the TAILENG mine tailings database to investigate potential relationships between the particle fea-tures and the particle size distribution and the critical state properties. Towards this end, the crit-ical state line is evaluated for a range of mine tailings with broad gradations and compressibility, defining ¿and ¿, with known particle size distributions. This information is subsequently used to investigate potential correlations. Insights from the observations are shared, and potential funda-mental mechanisms in explaining correlations between the critical state properties and particle features are discussed.