Seismic Induced Flow Failures of Mine Tailings Including a Failure Case History from Chile
The 2010 M8.8 Maule Chile earthquake caused damage over a large area of the country. Of particular interest was the flow failure of a gold mine tailings dam in the central region of Chile. A 25m high tailings dam experienced liquefaction due to strong ground shaking and flowed downslope as far as 350m resulting in several fatalities as well as degradation of the surrounding area. When tailings material liquefies it often behaves like a non-Newtonian fluid, requiring threshold shear stress before exhibiting strain rate dependent shear strength. The transition from liquefaction triggering to steady state flow, to runout involves interesting and complex physics that will be discussed. Predicting the stability of tailings dams subjected to earthquake shaking requires an estimate of the residual strength of the liquefied material. Post-earthquake field investigations of the Chile failure established the in situ engineering properties (SPT, CPT, VS) of the tailings material, and the liquefied residual strength for the failure was derived through the back calculation. The results augment the existing worldwide database to be used for future predictive models that help prevent similar failures in the future.
Moss, Robb, "Seismic Induced Flow Failures of Mine Tailings Including a Failure Case History from Chile" (2018). Public Lecture Series. 133.