Abstract
As global demand for minerals rises, mining operations are extending mine life and increasing production, driving the need for efficient tailings and mine waste storage. Simultaneously, the industry is striving to reduce water consumption and enhance risk mitigation. Dewatering technologies, such as thickening and filtering, are emerging as preferred alternatives to conventional tailings management methods. Thickened tailings are layered and compacted into stable, self-supporting structures that eliminate the need for operational water ponds and large retaining embankments. Co-disposal with mine waste, such as waste rock, offers another promising approach. Unlike conventional facilities, compacted tailings deposits are moisture-conditioned and compacted to remain partially saturated, typically exhibiting dilative behavior under operational loads. Despite these advantages, compacted filtered tailings storage facilities present unique geotechnical challenges. As spatial constraints tighten and production increases, tailings storage facilities are designed to accommodate larger volumes by increasing deposition heights, leading to higher effective stresses on underlying layers. Material thicknesses can exceed 100 meters, resulting in confinement pressures greater than 1 MPa. Evaluating material behavior under high-pressure conditions is essential, particularly the potential transition from dilative to contractive response, which could impact long-term stability, as materials initially exhibiting dilative behavior at lower pressures may transition to a contractive response at higher stresses.
This study presents a comprehensive laboratory investigation of a co-disposal compacted filtered tailings facility currently under pre-feasibility design stage. The experimental program included conventional undrained triaxial tests on tailings specimens at high stresses (up to 4.5 MPa) across various densities, large-scale isotropically consolidated undrained triaxial tests on tailings-waste rock mix samples, and one-dimensional consolidation tests exclusively on tailings specimens. A comparison between the mechanical behavior of tailings-waste rock mixtures and pure tailings is also discussed.
Findings provide insights into the geomechanical behavior of compacted filtered tailings under high-pressure conditions, across various tailings to waste rock mixtures, contributing to the development of safer and more reliable tailings storage strategies.
Authors
- Nicolás Alscher, Consultant (Civil/Geotechnical Engineering) | SRK Canada
- Ignacio Cueto, Senior Geotechnical Engineer | SRK Argentina
- Leonardo Carrizo, Staff Consultant | SRK Argentina
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