Abstract

This study estimates the fundamental frequency of an 85 m height sand tailings dam in Central Chile using the singlestation Horizontal-to-Vertical H/V Spectral Ratio Method (HVSR), calculated from seismic ambient noise and earthquake records. The dam was constructed by compacting hydraulically deposited sands classified from integral copper tailings, following the downstream construction method. A proper estimate of the dam fundamental frequency is critical for evaluating its seismic response and secure the safe tailings containment when subjected to intense ground motions generated by interface and intraslab earthquakes. Results from the HVSR method are compared with those of the Standard Spectral Ratio method (SSR) calculated as the ratio of the response of the dam crest and that recorded at the dam toe. The fundamental frequency of the dam is about 0.9 Hz in the dam central part away from the abutments, but differences in the vibration frequency are identified along the downstream slope and along the crest axis from the north to south abutment. An analytical relationship between the dam fundamental frequency, the dam height, and the shear wave velocity (Vs) profile is validated.

Abstract

A combined ground-based slope stability radar (SSR) and satellite-based (InSAR) monitoring system was trialled at a remote mine site in the Northern Hemisphere in order to investigate relative changes in displacement experienced by a mine waste storage facility. The relative changes in displacements along the InSAR line-of-sight (LoS) were compared to the relative changes in displacement provided by the ground-based SSR LoS. Although the two LoS are different, this study showed good agreement between the magnitude of relative displacements observed by both remote sensing technologies on the slope of the facility. Additionally, the study looked at the effectiveness of InSAR and SSR on capturing relatively shallow operational works undertaken on the tailings storage facility slope. Results showed that SSR is able to provide near real-time information about progressive trends in displacements and alert mine site personnel of potential areas that might need attention. InSAR could detect anomalies in surface deformations during the period when SSR did, but the radar signal was sufficiently low to not unequivocally attribute these responses to real surface deformations