Determination of the soil-water characteristic curve for multimetal tailings of the mining industry of Chile

Abstract

Tailings storage facilities are exposed to a series of phenomena that promote the desaturation of the materials, e.g. seepage and evaporation fronts. The desaturation generates negative pore pressure, the so-called suction, in the pore space, which controls
unsaturated seepage, transport of solutes, and  shear strength of the facility. If these phenomena need to be characterized, the Soil Water Retention  Curve (SWRC) is needed. This curve relates water content and suction. The construction of the SWRC in fine-grained soils requires significant equalization times, when using conventional direct methods, which limits its routine  determination. Therefore, practitioners use approximate models, which are not commonly available for tailings. Regarding this,
the present study explores SWRC determination in tailings samples recover from 13 tailings in Chile. A simplified estimation model is proposed based on basic properties of the material, e.g. fines content, saturation water content and the soil’s specific gravity.
This type of model will allow for the construction of the SWRC in the early development of engineering for tailings. In addition to this, unsaturated permeability of the tailings is characterized.