Evaluation of the Liquefaction Susceptibility of Filtered Iron Ore Tailings from the Iron Quadrangle (Brazil)

Abstract

Over the last few years, there has been a substantial increase in the degree of complexity of requirements regarding the licensing of tailings dams in Brazil. The stacking of filtered tailings is currently proposed as an alternative solution for tailings storage facilities; however, there are numerous challenges to understand and manage these structures in regions of high rainfall and high disposal rates. In this context, the objective of this article is to evaluate the liquefaction susceptibility of filtered iron ore tailings, based on field (piezocone) and laboratory tests (characterization and triaxial compression), both performed at an experimental landfill, located in the Iron Quadrangle (Quadrilátero Ferrífero), Minas Gerais state, Brazil. Therefore, a few methodologies were used to evaluate liquefaction susceptibility by means of the critical state theory, furthermore the fragility index of the material were also evaluated. Results indicated that the constructive method used in the experimental landfill (i.e., compaction energy, moisture and layer thickness) resulted in variability in the in-situ void ratio, indicating susceptibility to liquefaction for materials on depths greater than 0.75 m from compaction surface. In addition, from laboratory tests it was possible to determine the critical state line of the filtered tailings.