Perceived and realised benefits of paste and thickened tailings for surface deposition

Abstract

Interest in the potential use of high density, thickened tailings has recently increased significantly. Reasons for considering this new technology vary across projects, but commonly include the need to conserve water, perceived lower risk of catastrophic failure, potential easier closure or even reduced overall costs. As with any new technology, there has been some tendency to overstate its potential benefits. This paper reflects on whether or not the potential benefits that have been attributed to paste and thickened tailings have been realised. Using a grading system, thirteen benefits that were ascribed to the new technology some years ago are evaluated. Data are taken from case studies, and it is suggested that the key proven benefits appear to be reduced operating costs in some cases, reduced wall-building costs and reductions in water consumption. One key potential benefit that has not been universally achieved is a reduction in the footprint of the tailings facility. Reports in the literature highlight the sometimes confusing nature of trade-off studies. Unless full life-of-mine costs are considered, these studies can be misleading and incorrect. The need to establish a consistent basis for comparative studies is discussed.

Synergising water and energy requirements to improve sustainability performance in mine tailings management

“…This is due to the difference in the amount of mass solids contained in the tailings. Conventional tailings typically consist of 30% solids and P&T consists of up to 70% solids (Fourie, 2012). Some of the advantages of P&T tailings are identified by Jones and Boger (2012), and Boger (2013) including maximizing density of tailings in the TSF,…”

“…This enables Alcoa to reduce the total volume of waste and recycled water, and to recover caustic materials with total saving costs of approximately A$ 10 M/year (Cooling, 2007, Boger, 2009, Boger, 2013. Other examples of rheology benefits in mine tailings operations include Sunrise Dam, a gold mine in Western Australia which was able to reduce their mine tailings operational costs by approximately A$ 0.28 per ton when applying Thickened Tailings (TT) (Fourie, 2012). The Chihong mine in China was able to produce cemented paste backfill based on rheological experiments by increasing percent solids up to 80% (Yin et al, 2012), and the Sangan iron mine project in Iran recovered 0.87 Mm 3 of water when applying paste thickening technology (Rashidinejad and Naraghi, 2011).…”

Surface erosion effect on tailings

“…There are also many other advantages to considering dewatered (thickened, paste, or filtered) tailings as a tailings management option, including improved geotechnical performance, reduced closure/reclamation costs, and even enhanced permitting expediency. Some key issues have been assessed (Fourie, 2012), leading to a conclusion of perceived and realised benefits of the dewatering tailings technology.…”

Durability, strength, and stiffness of compacted gold tailings – cement mixes

“…Although this method requires a high amount of water and is not eco-friendly, it is widely employed because D r a f t 3 of its cost effectiveness (Adiansyah et al 2015). Boger et al (2012), Fourie (2012) and Moolman and Vietti (2012) claim that the implementation of new techniques such as thickened tailings (TT) and tailings paste (TP) technologies is capable of reducing future cost of mining rehabilitation and maintenance. Additionally, Boger (2011) affirms that these technologies increase the mine liability and hence the susceptibility to environmental damages.…”