*This is an abstract only. No full paper is available for this abstract.* In the last decade, the mining industry has responded to the sustainable development agenda through the Global Mining Initiative, the International Council on Mining and Metals and other venues. While progress has been made in a number of areas, an improvement in mine waste management (tailings) has been mixed. Incidents of poor mine waste management practice are one of the most conspicuous and negative features of the industry. Tailings spills, dam failures, seepages, unrehabilitated sites and cases of direct discharge to waterways have resulted in severe and long-term environmental and social consequences._x000D_
The resource industries, which include minerals, coal and the sand mining of oil, are the world's largest producers of waste. Much of this waste is produced as a fine particle suspension that is pumped to a storage area, generally at a low concentration, where it behaves like a Newtonian fluid. Simply removing water from the suspension and reusing and recycling water represents a step towards a more sustainable practice in the industry. As the concentration of such a suspension is increased by dewatering, the materials exhibit non-Newtonian behaviour, which is characterised by shear thinning, a yield stress and, in some instances, thixotropic behaviour. Such high-concentration, non-ideal (dirty) suspensions in the resource industries has meant that new rheological methods and techniques were needed for both shear and compression rheology to measure and interpret the basic flow properties. In addition, some older empirical techniques needed to be modified and interpreted in a more fundamental way so that the results could be used in design._x000D_
Dewatering to a high-concentration, paste-like consistency and the transport of the high-concentration suspension to tailings storage has resulted in dry stacking, which was pioneered by the alumina industry in the 1980s. Dry stacking has been made possible by significant advances in thickener design through the development of compression thickeners and advances in pump technology._x000D_
The feed to a compression thickener generally comes from the last clarifier/thickener in the extraction process. The stream is then flocculated again. Flocs form in the compression thickener, and water is separated from the flocs as they settle and form a bed. Additional water is removed as a result of aggregate densification, bed compaction and shear effects from raking. This material is then pumped with a high shear rate pump and transferred via a pipeline to a disposal area. Depending on the shear rates and shear history seen in the pump and the pipeline, the high-concentration flocculated material can be degraded where the flocculated structure has been destroyed. The concentrated suspension discharged to the storage area is a non-aggregating suspension. Further dewatering occurs as a result of evaporation, yielding a solid-like material that allows dry stacking._x000D_
A more recent process is the use of inline flocculation where the compression thickener is eliminated. The idea of inline polymer flocculation is not new. In the 1980s, the US Bureau of Mines demonstrated the process for dewatering coal tailings. There are now many patents in the area (both existing and pending) about which there is an air of secrecy. However, there are at least two videos on the web illustrating the process._x000D_
In inline flocculation, the flocculant is added in the pipeline in such a way as to establish optimum flocculation upon discharge to the disposal area, whereupon rapid water release occurs. This inline flocculation produces a flocculated, concentrated tailings, whereas compression thickeners can produce a non-flocculated concentrated tailings after pumping to the deposition site. In principle, both of these could produce dewatered tailings at the same solids concentration. However, there are some obvious advantages to successful inline flocculation. The large capital costs associated with compression thickeners are eliminated and the tailings can be pumped as a low-concentration fluid in turbulent or transitional flow, thus reducing operating costs relative to paste pumping and the uncertainties associated with settling in a laminar flow pumping situation. This presentation is an overview of 30 years of work with the resource industries on tailings minimisation. Aspects have been published in the proceedings of the Paste and Thickened Tailings conferences held annually since 1999 , in Chemical Engineering Science (Boger, 2009) and now in Annual Review of Chemical and Biomolecular Engineering (Boger, 2013)._x000D_
REFERENCES Boger, D V, 2009. Rheology and the resource industries, Chemical Engineering Science, 64:4525-4536._x000D_
Boger, D V, 2013. Rheology of slurries and environmental impact in the mining industry, Annual Review of Chemical and Biomolecular Engineering, 4:239-257._x000D_
CITATION: Boger, D V, 2015. Advances towards more sustainable management of mine tailings, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 3-4 (The Australasian Institute of Mining and Metallurgy: Melbourne).