UNDRAINED SHEAR BEHAVIOR OF MIXED WASTE ROCK AND TAILINGS
Matteus Hamade1; Christopher Bareither1
1 Colorado State University
Resumo
General Topic/Theme: Shear behavior of mixed mine-generated waste. Sub-theme: Evaluation of shear behavior of synthetic waste rock and tailing mixtures. Abstract: The risks associated with storage and long-term management of mine tailings in impoundment facilities highlights the importance of finding alternative methods for mine waste management and potential reuse applications. Mixtures of mine waste rock and tailings (WR&T) have been evaluated for beneficial reuse applications and as a management technique to decrease the volume of mine waste required for storage. Mixing WR&T has been researched to decrease acid rock drainage (ARD) potential from waste rock piles via sealing the large porous network of waste rock with low hydraulic conductivity fine-grained tailings. The coarse-grained material contributes on low compressibility of the WR&T mixture, expanding possibilities of reuse. There has been additional focus on understanding other engineering properties of WR&T mixtures to use mixed mine waste for engineering solutions in earthwork construction (e.g., road base) or water-balance covers for waste containment facilities. The objective of this study is to evaluate the effect of mixture ratio (R) and tailings composition on the shear behavior and shear strength of mixed mine WR&T. The mixture ratio is defined as the dry mass ratio of waste rock to tailings and can range from R = 0 as pure tailings to R = ∞ as pure waste rock. An optimum mixture ratio (Ropt) exists for a given waste rock void ratio and represents a mixture where tailings completely fill void space of the waste rock. The focus off this study is on WR&T mixtures higher and lower than Ropt to assess shear behavior as the material transitions from a predominantly tailings structure (R < Ropt) to predominantly waste rock structure (R > Ropt). Shear behavior of tailings, waste rock, and mixed WR&T will be measured in consolidated-undrained triaxial compression. Two types of synthetic mine tailings and one synthetic mine waste rock were
Palavras-chave: Geoenvironmental; Mine Waste; Shear Behavior; Shear Strength; Triaxial Test