On the Behavior of Bauxite Tailings under High Stresses

Abstract

Despite the vital importance to the contemporary economy, some drawbacks are mainly associated with the waste derived from mining activity. Essentially, this waste consists of tailings that end up being hydraulically disposed of in large impoundments, the tailings dams. Thence, as the dams are enlarged to accommodate higher amounts of materials, the stress states at which the deposited tailings are submitted change. This may be a concern for the stability of such structures once the geotechnical behavior of this sort of material may be complex and difficult to predict considering the existing approaches. Thus, the present study concerns the mechanical response of bauxite tailings under a wide span of stresses, ranging from 25 kPa to 4,000 kPa. One-dimensional compression tests, CIU, and CID triaxial tests were carried out on undisturbed and remolded samples of the bauxite tailings. The after-shearing grain size distribution was, as well, characterized. The results have shown a stress-dependency of the critical state friction angle for the intact material which may be related to fabric alterations derived from structure deterioration and particle breakage.