Which mine tailings are suitable for repurposing?

Start with the material you have, not the commodity, as tailings associated with the same commodity can yield different outcomes. Two iron ore operations, for example, may generate materials with distinct characteristics that suit different applications. The same applies to copper, gold and polymetallic operations.

The first step involves representative sampling and characterisation, which builds a detailed picture of the material and how it might perform across different fields. That work typically includes chemistry, mineralogy, particle size distribution and liberation studies. Together, these show how the material is distributed within the tailings and what uses those streams can support.

The presence of contaminants alone does not necessarily prevent reuse. Fine sulphide tailings often raise concerns because they can contain elevated levels of contaminants. They may also be too fine for direct use in applications that rely on coarser material.

Mapping where contaminants occur in the material, and understanding how they can be separated from the non-metallic fraction, often uncovers non-metallic streams that can support reuse. Contaminants associated with sulphides, for example, may be concentrated into a smaller stream through processing. If that happens, the remaining silicate-rich fraction may contain substantially lower contaminant concentrations and, subject to environmental testing and classification, may be suitable for beneficial reuse.

Projects may use magnetic separation, gravity separation, desliming and flotation concentrated contaminants into a smaller stream to produce a cleaner non-metallic material, which can serve a wider range of reuse options.

Beyond understanding the material composition, you should have a clear understanding of whether that material can satisfy an industry’s requirement. In many cases, the material can be separated into multiple sub-streams, each supporting a different product or end use. Representative sampling, characterisation and preliminary product screening provides a basis for meaningful discussion with potential end users.

Concrete manufacturers and ceramics producers evaluate feedstocks against their product specifications. Tailings only become relevant when they can satisfy those requirements, which may include mineralogy, chemistry, particle size, moisture content, contaminants, consistency and available volumes.

Engage in early discussions with manufacturers and end users, alongside your environmental assessment and product validation. Those conversations reveal whether the material can meet industry specifications and support a commercial application.