Bauxite Residue Management

Bauxite Residue

Bauxite residue, known as red mud, is a solid waste produced in the Bayer process, the process of alumina extraction from bauxite ores. Bauxite Residue can be stored in a variety of ways. The method of storage depends on number of factors, such as local topography, how much rainfall an area gets, whether there is regular or irregular seismic activity recorded, the type of mineral being mined and how close the mine is to populated areas.

Identifying the most appropriate method of construction is important to ensure the safe and sustainable operation of a facility. Bauxite Residue storage facilities follow one of three wall construction designs: these are downstream, upstream and centerline.

Downstream

Downstream designs start with an impervious starter dam. The residue is then discharged into the dam and as the embankment is raised, each new wall is constructed and supported on top of the downstream slope of the previous section, so the dam crest moves downstream with each raise. The downstream design was developed for areas with seismic activity and high rainfall or water collection.

Upstream

Upstream construction begins with a starter dam. The residue is then discharged into the facility where they form a beach. The deposited residue adjacent to the dam wall is allowed to drain and then can be compacted to be used to form the foundation for subsequent levels of the wall as the dam is raised. As such, the crest of the dam moves upstream with each raise.

Centerline

The centerline method is a hybrid of upstream and downstream designs. In Centerline construction, the dam is raised vertically from the starter dam. The dam crest therefore remains fixed relative to upstream and downstream directions as the dam is sequentially raised. This design method can also incorporate internal drainage to improve stability.