A study on the mechanical behaviour of three different fine-grained mine tailings

Mine tailings stored in the tailings storage facility (TSF) are normally loose and failure-prone for several reasons, such as liquefaction, erosion, overtopping, piping, and high excess pore water pressure (PWP). The investigation of the mechanical behavior of tailings material is essential for engineering design and safety evaluation of the TSF during mining operations, closure, and rehabilitation. As such, laboratory compaction, consolidation, and direct shear strength experiments are carried out on three different fine-grained mine tailings, named coal tailings (CT), red mud (RM), and gold tailings (GT). Compared to CT and RM, GT showed higher dry density at the optimum moisture content (OMC) and lower compressibility. The permeability of GT is similar to RM but much higher than that of CT. CT and GT showed the highest cohesion and angle of internal friction, respectively, among the tested materials. The direct shear test, among all the methods used, provided the highest dry density and lowest void ratio. The final state parameters obtained in compaction, consolidation, and direct shear tests are critically compared, which is the novelty of this study. This research explored useful information on the geotechnical properties of different tailings that can help mining operators and researchers effectively design and manage the tailings in the TSF.