Mining

Kenmare is mining the Namalope deposit. Mining is carried out by two dredges. The main advantage of dredge mining is its lower cost of production compared to alternative mining methods, such as dry mining.

The dredges cut the ore at the base of the ore face, allowing the mineral bearing sands to collapse into an artificial freshwater dredge pond approximately 800m long, 300m wide and up to 15m deep. The mineral-bearing sands are pumped by the dredges to the WCP which floats in the dredge pond. The first stage of the WCP uses two trommels to reject oversize material, with the underflow material passing into the surge bin. The feed is then pumped from the surge bin to banks of spiral separators which separate the heavy minerals (HMC) from the silica sand and clay (slimes) tailings. HMC is a mixture of the valuable minerals ilmenite, rutile and zircon as well as some non-valuable constituents including aluminosilicates and any remaining silica. The HMC, representing approximately 5 per cent by weight of the total sand mined, is pumped overland to the MSP where it is stockpiled prior to further processing.

Tailings, which consist of a coarse silica fraction (sand) that settles immediately, and a fine clay fraction (slimes) that settles less quickly, are deposited at the rear of the dredge pond where they are spread out for future rehabilitation. This rehabilitation involves contouring the deposited sand and then covering it with a layer of clay-rich slimes mixed with sand. The slimes and sand layer helps the subsoil retain moisture and nutrients to aid re-vegetation of the tailings.

Finally, the stored topsoil containing seeds, organic material and microorganisms are placed onto the tailings. The rehabilitation process is completed by fertilising, seeding or planting with a variety of native, other species and food crops. The rehabilitation process is being fine-tuned with input from local communities, competent authorities and non-governmental organisations.

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