Paste and thickened tailings – myth busting and clarification

Abstract

It is the contention of this paper that there remains considerable confusion regarding the mechanisms and benefits of thickened tailings schemes. The terminology and interpretation of terms like 'thickened tailings' and 'paste' receive some consideration, in light of some observed contradiction in the industry. It is also noted that a number of tailings related misconceptions prevail amongst tailings practitioners. This paper attempts to clarify some of these issues, with the intention of dispelling some tailings myths. The subject of tailings beach slope prediction is one particular topic that deserves some consideration in the interests of clarity. A large portion of this paper is devoted to this topic, which has been approached from a number of directions over the past 40 years. Various prediction methods have been presented. Some prediction methods are analytical, with no need for any flume testing. Others have relied on a deposition test in a flume. The use of different types of flumes and deposition tests, either for providing validating data or input data, has created a great deal of confusion over what works and what does not, what is relevant and what is not. There has also been further confusion created by the presentation of the results, with some workers presenting fitted data as predictions. This paper discusses the mechanism of tailings deposition, with a view to evaluating the applicability of some of the approaches that have been presented. Various flume types and their relevance to the process are then discussed. Deposition tests and trials are also discussed in terms of the beach slopes that have been observed. Finally, some protocols are proposed for making the presentation of data more consistent and transparent.

The influence of slurry density on in situ density

“…Hypothesis A has been suggested by Barrera and Riveros (2006). It has also been explicitly outlined by Fitton and Seddon (2013), who state that following incremental deposition and settling on a thickened tailings deposit "there is a thin layer of tailings on the beach, at a density that is independent of the concentration of the slurry it was deposited from. All subsequent drying and consolidation processes are independent of the initial slurry density".…”

Aplicação De Polieletrólito Catiônico Para Desaguamento De Lama Vermelha: Produção De Sedimentos Adensados

“…Conforme as polpas são adensadas para produção das pastas, as suspensões minerais passam a se comportar como fluido não newtoniano com tensão limite de escoamento, que é a tensão mínima necessária para que ocorra a deformação irreversível do material. Tendo as pastas minerais a característica de apresentar tensão limite de escoamento mínima de 200 Pa [4], esta variável denota a transição entre o comportamento de polpas e pastas. Assim sendo, o monitoramento desse parâmetro é fundamental para o projeto de disposição dos rejeitos como pastas minerais [1][2][3][4].…”

Rheology applied to the environmental management of mineral tailings: focus on safer disposal and water reuse

“…The difference between pastes and thickened tailings is determined by yield stress, which measures the ability of the tailings to withstand deformation. Pastes are thickened tailings with a lower limit of the yield stress of 200 Pa (Clayton et al, 2003;Boger, 2013;Fitton and Seddon, 2013). Thus, a good understanding of the rheological properties of paste is important for the mining industry.…”