ICOLD – sustainable design and post-closure performance of tailings dams

Abstract

The International Commission on Large Dams (ICOLD) is a non-governmental international organisation that was established in 1928 as a forum for the exchange of knowledge and experience in dam engineering. This organisation is made up of various subcommittees, one of which is the Committee on Tailings Dams and Waste Lagoons. Formed in 1928, this subcommittee has produced a number of bulletins related to tailings dam design. The next bulletin, "Sustainable Design and Post-Closure Performance of Tailings Dams", will be published in 2011/12 for tailings dam designers intending to achieve sustainable development. Sustainable development in this paper is defined according to the Bruntland Report (UNWCED, 1987): "development that meets the needs of the present without compromising the ability of future generations to meet their own needs". This means that mining projects, including tailings management facilities (TMFs), should be financially viable, technically appropriate, environmentally sound and socially responsible (ICMM, 2008). In order to fulfil that brief, closure of TMFs need to be managed carefully. This new ICOLD Bulletin is intended to be a guide in this process. The Bulletin is compiled into three major sections, with in-depth discussion on the following:  Sustainable closure principles, covering closure objectives, closure design life, the influence of deposition methods, financial principles, regulations and risk management principles.  Sustainable design considerations, covering consequence classification at closure, long term physical stability, ecological and social stability.  Long-term monitoring: covering instrumentation and control after remediation has taken place. This paper sets out some of the guiding principles and details that will be contained in the new ICOLD bulletin.

A importância das pesquisas relacionadas aos desastres: colapso da barragem de Fundão Mariana-MG

“…A tarefa de armazenar rejeitos de minas com segurança e eficiência é substancial e, crucialmente, quase certa de estar em uma escala significativamente maior no futuro. As partículas dos rejeitos geralmente são angulares a muito angulares, e essa morfologia impõe um alto ângulo de atrito nos rejeitos secos (Bjelkevik, 2005).…”

O que significa descaracterizar barragens de rejeitos de mineração? Uma revisão sistemática da literatura

“…Segundo Bjelkevik (2011), o planejamento do fechamento de barragens de rejeito deve começar concomitantemente ao planejamento da estrutura a fim de Figura 1 -Infográfico sobre a geração de rejeitos e métodos de alteamento de barragens de rejeitos.…”

Critical gradients for tailings dam design

“…This rule is, despite the lack of scientific verification, commonly accepted for the long term stability of tailings dams' slopes in Sweden. According to the Swedish dam safety guidelines RIDAS, the safety factor FS determined by limit state analysis being 1.5 is regarded being sufficient (Bjelkevik, 2005a). However, a major problem for this assessment is the determination of tailings' friction angle, as it can vary between 18º up to 45º (Jantzer et al, 2008).…”

“…These mounds were studied with respect to stable slope angles; their inclination varies from 16 to 28º. There are additional examples of manmade earth mounds, burial and entombment sites all over the world that are up to 6,000 years old (Bjelkevik, 2005a). The landscape in Scandinavia is characterised by numerous lakes as a result from an inland ice cover that was responsible for sedimentation and erosion.…”

“…The increasing demand of metals and minerals has made it economical to mine low-grade deposits, which in turn results in immense quantities of waste material. In fact, mine wastes are the largest waste volumes produced on earth (Mitchell and Soga, 2005;Bjelkevik, 2005a). These waste volumes comprise fine grained particles with varying characteristics dependent on the origin of the ore and different extraction processes.…”