Résumé - Abstract
Fluid fine tailings (FFT) are the by-product of mineral extraction of almost all mining operations. Conventionally, these waste materials are transported hydraulically as slurry and stored behind dams. These dams, which are constructed from the coarser fraction of the tailings materials, cause serious problems such as the poor stability of impoundments and land reclamation. The second waste stream of surface mining operations is the waste rock which is typically hauled to waste dumps. These dumps cause geotechnical stability problems and are prone to generate acid rock drainage (ARD).
The reoccurrence of the problems mentioned above has encouraged the industry to seek an alternative approach to conventional tailings and waste rock disposal methods. To remediate these predictable issues, an engineered homogenous mixture of waste rock and tailings, paste rock, is proposed to be deposited in self-supporting dry stacks. This homogenous mixture would address the conventional disposal issues by benefiting from both waste streams' desirable properties. This research investigates the characteristics of paste rock, which depend on the properties of its constituent materials and their mixture ratio. In this research, the geotechnical and geochemical characterization of paste rock with several different mixture ratios is investigated using column permeability tests and computerized axial tomography (CAT) scan imaging. Also, centrifuge tests and slurry consolidometer tests will be conducted to replicate material deposition and analyze the unsaturated mixture's compression and self-weight consolidation behaviour. Additionally, the slurry consolidometer test results will be numerically modelled using FLAC3D software to investigate porewater pressure changes during the material's stacking and simulate mixture deformation. The results of these numerical modelling can be upscaled to understand the full-scale field performance.