Stiffness degradation of non-plastic copper ore tailings

The accumulation of tailings from ore extraction processes presents significant challenges in geotechnical engineering and environmental management. Tailings possess complex mechanical behaviour and unique characteristics, making them particularly sensitive to seismic activity. This study investigates the stiffness degradation of two non-plastic copper ore tailings collected from a seismically active region in Spain. An extensive experimental programme comprising 72 resonant-column tests was conducted to examine the dynamic behaviour of these materials under various isotropic stress conditions and shear strain levels. The findings were compared with those of other soils, including two well-characterised sands, providing a comprehensive analysis of normalised shear modulus and highlighting the distinct dynamic behaviour of the tailings. The experimental results offer a detailed analysis of the stiffness degradation, emphasising their unique dynamic behaviour and proposing a unified model to reliably describe the shear modulus degradation of these materials. The study underscores the importance of characterising tailings due to their inherent variability, enhancing the safety of tailings storage facilities in seismic regions.