Simulation of tailings release in dam break scenarios using physical models

Tennison Freire Souza Jr,Sidnei Helder Cardoso Teixeira

doi:10.1590/0370-44672018720098

Tennison Freire Souza Jr, Sidnei Helder Cardoso Teixeira

Open Access

https://doi.org/10.1590/0370-44672018720098

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Abstract

Abstract This article presents an experimental study performed to evaluate the volume of material released from the reservoir during a tailings dam failure event using models. To verify the influence of the parameters related to the breach geometry and the undrained shear strength (Su) in a failure event, 20 scenarios were simulated considering the absence of water in the reservoir. The material used to simulate tailings was bentonite, due to the similarity between the properties of the mud and mineral tailings sludge. Geometry and undrained shear strength were adjusted considering a scale factor of 1: 500. Regarding the studied parameters, the geometry of the breach was based on data from literature, whose lateral slopes were 0.50 H: 1V, 0.51 H: 1V and 0.5467 H: 1V in the trapezoidal breaches and 1: 1 (L / H = 0.97) and 1: 1 (L / H = 1.1) in the rectangular ones. The undrained shear strength ranged from 0.030 to 0.20 kPa. The results allowed to conclude that the mobilization of material increases with the average aperture width of the trapezoidal breach, being this the distinct behavior in rectangular breaches. Although the rectangular breaches had smaller average widths compared to the trapezoidal breaches, their base widths were larger and it is possible to infer that the mobilized volume depends on the geometry and the average width of the breach.

Highlights

The mining activity generates millions of cubic meters of materials extracted and handled in the beneficiation process each year
The amount of mobilized material increases with the moisture content of the material, which is dependent on its undrained strengths;
The lateral slope of the breach influences the amount of post-failure mobilized material;

Summary

Introduction

The mining activity generates millions of cubic meters of materials extracted and handled in the beneficiation process each year. In the case of tailings, the produced amount depends on the used process for extraction, the ore concentration and the deposit location. The quantification of this material is complex, due the diversity of operations and technologies used in the extraction and processing technics. If the dams are inadequately built or designed, these structures represent a great risk to society, to the environment and to the economy. These materials raise uncertainties regarding their mechanical behavior, either due to the low shear strength or the variable permeability. Continuous monitoring of the material throughout the construction and operational process is necessary

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