Paste Tailings Research Articles

Dynamic imaging and modelling of multilayer deposition of gold paste tailings

Surface deposition of paste or thickened tailings is increasing contemplated as an alternative to conventional slurry deposition. One important challenge in managing paste is to predict the evolving geometry of the tailings stack during deposition. This study dynamically images multilayer deposition of paste in flows in flume and axisymmetric flows. Each layer is left to self-weight consolidate for a day before the next layer is placed. It is found that both the steady-state profiles and the dynamic flows can be modelled as a Bingham fluid using equations developed from lubrication theory. Yield stress and viscosity were determined using rheometry and slump tests. It is shown that the yield stress obtained from the slump test may overestimate the yield stress of significance to flow deposition; namely that yield stress that characterizes when the tailings stop flowing. The lubrication theory equations show that the overall angle of a tailings deposit at steady-state is dependant on the scale of the flow, which may explain the discrepancy between laboratory flume angles and field angles noted in practice.

Microstructural and geochemical evolution of paste tailings in surface disposal conditions

Surface paste tailings disposal has recently been proposed in the mining industry for the management of mill tailings. This new disposal method can represent an advantageous alternative to traditional tailings impoundments, as it favours water recycling and the control of free water during deposition, reduces the need for costly water-retaining dykes, and facilitates site rehabilitation. In this paper, the microstructural and geochemical properties of surface paste tailings were assessed. Column leaching tests were conducted on sulphide-rich paste tailings deposited under different configurations (cemented and uncemented). The leached samples were characterized and the results were compared to those obtained on the reference (unleached) samples. The paste microstructure was characterized by mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) microanalysis. A part of the study focussed on the impact of cracks, which were found to influence the paste reactivity observed for some disposal configurations. The paper illustrates how to use paste technology and a small amount of ordinary Portland cement (0.66 wt.% in configuration L2) to stabilize sulphide-rich acid generating tailings (AP = 953 kg CaCO 3/t).

Modelling evaporation of paste tailings from the Bulyanhulu mine

Accurate predictions of drying rates are desirable to optimize surface deposition of thickened or paste tailings. A series of laboratory and field trials were implemented to study evaporation from tailings at the Bulyanhulu gold mine and were compared with numerical simulations using the unsaturated flow model SoilCover. The laboratory tests included two “large-scale” experiments on 10 cm thick layers of tailings 2 m by 1 m in plan, and a smaller column test on a 20 cm thick and 20 cm diameter sample. Data monitored during these tests included albedo, volume change, degree of cracking, matric suction, water content, and drying rate. Field data included gravimetric water contents and albedo values. The model could reasonably simulate the laboratory experiments when adjustments were made to account for self-weight consolidation and the effect of volume change on the relative permeability function. The model could simulate drying in the field for up to 3 weeks after deposition before the accumulation of gypsum and magnesium sulphate salts began to affect evaporation. Cracking and salt accumulation were observed both in the laboratory and in the field. A general model for simulating drying from paste tailings should incorporate the effects of cracking and salts.

Tailings management facility topography modelling to identify flow accumulations and pond geometry

Water management is one of the key parameters influencing the stability of a tailings storage facility. Most conventional impoundment failures have occurred because of incorrect water management leading to loss of freeboard and eventual overtopping. These events normally occur during or after storms or when there is a rapid ingress of water into the impoundment (e. g. upstream snow/ice melts). For conventional tailings facilities with uneven beaches a rise in the supernatant pond can cause localised freeboard loss increasing the risk of overtopping. Attempts have been made in the past to try and model the surface of a tailings facility mainly by using photogrammetry and LIght Detection And Ranging (LIDAR). For thickened and paste storage facilities the low elevation areas of the deposit can be determined to establish future discharge flow paths, areas of acid generating tailings that require cover and the current volume of the tailings that are currently stored. This paper presents a realistic technique that can be used on conventional, thickened and paste tailings facilities to model the topography and accurately determine water and tailings volumes. Using Geographical Information System (GIS) software a conventional tailings impoundment can be modelled to determine available water storage volumes and the areas that have the lowest freeboard and are more susceptible to overtopping.

A Novel Approach in Preparing a High Strength Total Tailings Paste Backfill Through Tailings Agglomeration

Mineral Resources EngineeringVol. 06, No. 02, pp. 75-87 (1997) No AccessA Novel Approach in Preparing a High Strength Total Tailings Paste Backfill Through Tailings AgglomerationLaxman Amaratunga and Glen HeinLaxman AmaratungaSchool of Engineering, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada Search for more papers by this author and Glen HeinLaurentian University Tailings Agglomeration Research Laboratory Sudbury, Ontario, P3E 2C6, Canada Search for more papers by this author https://doi.org/10.1142/S0950609897000097Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractA large problem in the mining industry from a waste disposal and environmental perspective is the effective disposal of mill tailings. The use of tailings in underground backfill has been the most common means of reducing the quantity of tailings for surface disposal in tailings ponds. While the coarse fraction of the tailings are used, only a small percentage of the fine tailings are incorporated into underground "paste fills", with aggregates often needed to enhance the strength. This paper evaluates the potential of utilizing agglomerated fine mill tailings as an aggregate resource in the production of a total tailings paste backfill, thereby allowing a greater percentage of fine tailings to be disposed of underground. It was shown that agglomerated tailings can be effectively utilized as an aggregate resource in producing a high strength total tailings paste backfill. In developing this paste backfill it was found that high strength and low binder costs can be achieved by using Type C fly ash and Portland cement as binders. By utilizing this approach to paste fill design, operational benefits such as the elimination of the need for outside aggregate resources and high strength are realized. This approach as well has environmental benefits such as reduced tailings impoundment on the surface and the associated reduction in acid mine drainage potential. FiguresReferencesRelatedDetails Recommended Vol. 06, No. 02 Metrics History PDF download