Influence of Non-Plastic Fines Content on the Mechanical Behavior of Filtered Iron Ore Tailings
Bender elements, Hollow cylinder, Critical state, Filtered stacks
The mining industry is one of the largest contributors to Brazil's PIB. In the last decade, two major dams constructed in Brazil for tailings disposal have ruptured, causing the deaths of hundreds of people and severe environmental damage. A promising alternative for safer disposal is the stacking of filtered tailings. Recent failures in such structures highlight the need for more extensive investigation of these materials and the adoption of measures to reduce mining risks. Enhancing the safety of tailings disposal is crucial, especially in the current scenario where the impacts of climate change are contributing to an increase in extreme precipitation events. Combining strength and stiffness results has proven to be promising in evaluating the susceptibility of mining tailings to flow liquefaction. However, the percentage of fine particles present in the material significantly affects its shear strength, liquefaction potential, and stiffness. In this context, the present research aims to evaluate the effect of the percentage of non-plastic fines on the maximum shear modulus, instability, and critical state parameters. For this purpose, various triaxial tests, bender element tests, resonant column tests, and hollow cylinder tests were conducted. The results demonstrate that the fines content directly affects the strength and stiffness parameters of iron ore tailings. These findings are relevant and aim to contribute to the construction of safer and more efficient tailings piles.