| Popis: |
Tailings dams retain the waste by-products of mining operations and are amongst the world’s largest engineered structures. Recent tailings dam failures highlight important gaps in current monitoring methods and a pressing need to advance research on tailings dam monitoring technologies, considering growth predictions for the mining of metals. At an active tailings dam in northern Canada, we combine ambient noise interferometry with a quantitative stress model to monitor shear wave velocity (Vs) changes. Changes in seismic velocities of less than 1% correlate strongly with water level fluctuations at the adjacent tailings pond. A stress model, calibrated using pond level recordings and Vs profiles obtained from cone penetration tests, demonstrates that the seismic velocity changes obtained with ambient noise interferometry are predominantly changes in Vs. Furthermore, this model constrains Vs changes to a depth of ~16 m, corresponding to uncompacted tailings below the dam. As Vs is used to assess the liquefaction potential of soils, this method provides important advances for understanding changes in dam performance over time. |
