How to Prevent Flow Failures in Tailings Dams

Roberto Rodríguez,Julio César Arranz-González,Cristóbal García-García,Francisco Javier Fernández-Naranjo,Alejandro Muñoz-Moreno,Ángel Brime-Barrios,Alberto Alcolea,Virginia Rodríguez-Gómez,Ana Vanessa Caparrós

doi:10.1007/s10230-021-00752-8

Abstract

Based on research carried out at 67 tailings dams in Spain: (1) tailings dams contain alternating sedimentary layers with contractive and dilative geomechanical behaviours; (2) tailings saturate quickly but drain more than 10 times slower due to the high-suction capacity of the porous sediments (2–300 MPa); and (3) over the long-term, a stationary flow regime is attained within a tailings basin. Four temporal and spatial conditions must all be present for a tailing dams flow failure to occur: (1) the tailings must experience contractive behaviour; (2) the tailings must be fully saturated; (3) the effective stress due to static or dynamic load must approach zero; and (4) the shear stress must exceed the tailings residual shear stress. Our results also indicate that the degree of saturation (Sr) is the most influential factor controlling dam stability. The pore-pressure coefficient controls geotechnical stability: when it exceeds 0.5 (Sr = 0.7), the safety factor decreases dramatically. Therefore, controlling the degree of tailings saturation is instrumental to preventing dam failures, and can be achieved using a double drainage system, one for the unconsolidated foundation materials and another for the overlying tailings.

Highlights

Tailings dams (TDs) failures have been widely addressed (e.g. Agurto-Detzel et al 2016; ICOLD 2001; AyalaCarcedo 2004; Oldecop et al 2008; Zandarín et al 2009; WMTF 2020), along with their environmental consequences
Numerous post-failure investigations have concluded that more than one defect in the design, construction, and/or operation must converge before TDs fail (Alonso and Gens 2006; ANCOLD 2019; CDA 2014; Crippen 2018; ICOLD 1982; Oldecop and Rodríguez 2006; Rico et al 2008; Rodríguez 2018; WISE 2020; WMTF 2020)
TDs are classified according to their operating status: active (Figs. 3, 4), abandoned (Figs. 5, 6) and restored (Fig. 5, Table S-1)

Summary

Introduction

Tailings dams (TDs) failures have been widely addressed (e.g. Agurto-Detzel et al 2016; ICOLD 2001; AyalaCarcedo 2004; Oldecop et al 2008; Zandarín et al 2009; WMTF 2020), along with their environmental consequences Numerous post-failure investigations have concluded that more than one defect in the design, construction, and/or operation must converge before TDs fail (Alonso and Gens 2006; ANCOLD 2019; CDA 2014; Crippen 2018; ICOLD 1982; Oldecop and Rodríguez 2006; Rico et al 2008; Rodríguez 2018; WISE 2020; WMTF 2020). TD failure is a consequence of a flaw of design, construction, or management, or a combination of these (Brown et al 1969; Caruccio and Geidel 1984; Jennings 1971; Martin et al 2002; Morgenstern et al 2016; Rodríguez 2018; Smith 1969; Van Zyl and Robertson 1980; Zandarín et al 2009). TD failure is a consequence of a flaw of design, construction, or management, or a combination of these (Brown et al 1969; Caruccio and Geidel 1984; Jennings 1971; Martin et al 2002; Morgenstern et al 2016; Rodríguez 2018; Smith 1969; Van Zyl and Robertson 1980; Zandarín et al 2009). Martin et al (2002) provide 10 basic rules of good practice for the design, construction, and management of upstream TDs that should

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Conclusion