The Richards Bay Minerals (RBM) heavy mineral-rich sands coastal dune deposits (Tisand, Zulti North) extend parallel to the beach. Mining was started within the Tisand lease just north of Richards Bay. Currently, the Zulti North mining lease (north of Lake Nhlabane) is being mined.

The deposit covers a coast-parallel dune belt some 20 km long and about 2 km wide. The height of the dune is about 60 – 110 m, with increasing altitude northwards.

Type of mineralisation: Coastal mineralised sands.

Quaternary heavy mineral-bearing aeolian dunes of the upper portions of the Maputaland Group (Sibayi and Kwambonambi Formations) resting on a Pleistocene beach are mined. Clay-enriched, weathered Kosi Bay Formation dune sands and the Port Durnford Formation estuarine deposits form the underlying beds. KZN Sands, located south of the Mhlatuze River, mined the clay-enriched, rubified weathering profile which formed within the older Umkwelane Formation dune ridge.

According to Wipplinger (1998) the dune sand contains about 10 % heavy minerals, on average consisting of 6.08 % ilmenite, 0.28 % rutile and 0.83 % zircon. The heavy mineral assemblage also comprises monazite and magnetite. The grade of the ilmenite is too low (49.7 % TiO2 on average) to be marketable in its existing form and thus has to be upgraded by a smelting process to produce an 85 % TiO2 slag.

Richards Bay Minerals (RBM) uses a system of ponds and floating dredges to mine the ore body, where heavy valuable minerals such as ilmenite, zircon and rutile are recovered from the sand.

RBM uses six floating dredges at four mine sites (B, C, D and E) at various places within the dunes. In areas inaccessible to the dredges, or in dunes which are higher than 60 m, dry mining is performed.

A large artificial freshwater pond is created in the dunes, on which float the dredger and concentrator plant. While the dredge removes the material from the front end of the pond, the tailings generated by the separation process are stacked at the back; as a result the pond continuously moves in a forward direction. Burrowing into the mining face of the dune, the dredger advances at a rate of 2 - 3 metres per day, depending on the height of the dune. As the sand face is undermined it collapses into the pond forming a slurry, which is sucked up and pumped to a floating concentrator. At this point, the heavy minerals are separated from the sand by exploiting differences in mineral density via a multi-stage circuit of sluices.

A portion of the magnetite and the chromium-containing minerals are removed magnetically, and the resulting heavy mineral concentrate (HMC) stockpiled for transportation by road to the Mineral Separation Plant (MSP).

Upon arrival at the Mineral Separation Plant (MSP), located at the smelter site, the heavy mineral concentrate is re-slurried and pumped into the feed preparation circuit. The nonmagnetic materials, including zircon and rutile, are concentrated for further processing in the dry mill. Roasting, smelting and slag and iron processes are used to extract the final products.

Products are several grades of ilmenite, titanium slag, rutile, zircon and high-quality pig iron. Monazite-rich talings are stockpiled, with RBM investigating its potential as a source of rare-earths.

The ilmenite is processed through an oxidizing roast followed by magnetic separation and is then partially reduced to an 85 per cent TiO2 slag in one of four six-in-line a.c. electric arc furnaces. The slag containing approximately 85 per cent titanium dioxide and a high-purity (low manganese) pig iron as a co-product.

The slag is milled and then classified into two product sizes suitable a ........