‘The Role Of Hydrocyclones In Tailings Management’ – Article Preview

Tailings management is, by its very nature, site specific; every tailings storage facility (TSF) has to contend with a unique series of risk factors depending on the site’s local climate, topography, hydrology, and the physical and chemical properties of the tailings themselves.

As an original equipment manufacturer (OEM), Weir Minerals cannot take a one-size-fits-all approach. Instead, the company works closely with its customers to understand their requirements and their site’s particular challenges; its process engineers help develop innovative flowsheets; and its product experts draw on their know-how and experience to support miners at every stage of the project.

This close customer collaboration has been fundamental in the development of Weir Minerals’ Cavex^® DE hydrocyclone. This double-effect classification unit – with two stages of separation incorporated into the one piece of equipment – works without the need for intermediary pumping, piping, or sumps.

Aside from being highly efficient, it is also increasingly being utilised to address some of its customers’ other operational challenges.

Tailings storage facility dam wall construction

The development and success of the Cavex DE hydrocyclone is attributable, in part, to the fact that South America is one of the most earthquake-prone regions in the world. Seismic activity is caused by complex interactions of the South American tectonic plate with adjacent plates along the Pacific, Caribbean and Antarctic coastlines, as well as by several hundred faults located throughout the South American plate itself.

Therefore, TSF dam walls need to be stable and reliable in the event of an earthquake. It is not uncommon for operators to utilise tailings in the construction of the dam wall; however, the sand needs to be of a certain consistency and quality to ensure the TSF’s integrity. The plant tailings are hydro-cycloned, producing a relatively coarse free draining sand that can be used to build the dam wall.

The relatively free-draining characteristic of the sand is defined by the mass fraction of particles of less than -200 mesh (75µm). This is a concept borrowed from the soil sciences where, by definition, free drainage occurs at a particle mass fraction of 5% passing -200 mesh. In tailings dam construction, sand is commonly regarded as relatively-free draining at 15% passing -200 mesh.

This requirement helps prevent liquefaction, the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid. For this reason, the Cavex DE hydrocyclone is also the ideal solution for mines located in regions that experience high levels of rainfall, where the risk of liquefaction is most severe.

Typically, tailings would have to pass through several stages of hydro-cycloning to achieve this sand quality; however, with the Cavex DE hydrocyclone, it can be achieved in a single stage.

With a conventional hydrocyclone, 35 – 40% of mass is usually sent to the underflow, however, with Cavex DE, it is approximately 45 – 55%.

This is a preview of an article that was originally published in the November/December 2022 issue of Global Mining Review. The full version can be read here.

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Read the article online at: https://www.globalminingreview.com/mining/29122022/the-role-of-hydrocyclones-in-tailings-management-article-preview/