Modern Mining August 2018

DIAMONDS

Volvo machines add muscle to Steyn Diamante’s fleet Steyn Diamante, arguably the most successful alluvial diamond miner operating in the Northern Cape, has bolstered its mining fleet over the past year with several ‘new generation’ high-end machines from Volvo Construction Equipment (Volvo CE), including an L350H wheel loader, the flagship of Volvo’s loader line-up, and three Volvo A60H articulated haulers, all supplied by Volvo CE dealer Babcock. Modern Mining’s Arthur Tassell recently visited Steyn Diamante’s Schutsekama mine to talk to Schalk Steyn, the company’s founder and CEO, and view the newmachines in action.

T he Schutsekama mine is located south-west of Kimberley on the Riet River, a tributary of the Vaal, downstream of the village of Ritchie. It is currently Steyn Dia- mante’s only active operation although the company has in the past mined at several sites along the Middle Orange River (MOR), which – along with the Vaal – is the main source of the Northern Cape’s alluvial diamonds. Steyn Diamante established Schutsekama in 2015 and the remaining mine life is currently esti- mated at seven to eight years. Explaining the mining operation at Schutsekama, Schalk Steyn says it is essen- tially a large-scale earthmoving exercise. “The diamond-bearing gravels, which are buried under up to 15 m of overburden, have a grade which only averages around 0,4 carats per hun- dred cubic metres of gravel, which is quite low

even by the standards of alluvial diamond mining,” he says. “So to

survive we have to move vast amounts of mate- rial as efficiently and economically as possible. Typically, we’ll handle between 700 000 and 850 000 tons of material a month.” Currently, there are two active pits at Schutsekama. Diamond-bearing gravel from the pits is mined by heavy excavators and then trucked just a few hundred metres to four Finlay 893 screens. The oversize material is scalped off and taken back to the pits where it is used for rehabilitation while the minus 100 mm fraction is then sent to the processing plant, which consists of a scrubbing section followed by eight Russian-made Bourevestnik X-ray sort- ers divided into three lines – oversize, medium and fines. The final concentrate is hand sorted. Says Steyn: “Traditionally, pan or DMS plants are used to process diamond-bearing gravels but we’ve been using the Bourevestnik technology since 2010. We find the machines are very effective and we’re very satisfied with the performance they deliver.” Steyn says that what makes Schutsekama profitable is the value of the diamonds recov- ered – which is generally in the range of US$1 500 to US$2 000 per carat – and the occasional recovery of very large stones. “The biggest we’ve had so far is a ‘fancy yellow’ of nearly 160 carats,” he states. Commenting on what makes for success in the hard, unrelenting game of alluvial diamond mining, Steyn says that management has to be hands on. “There’s no margin for error when you’re dealing with a low-grade deposit such as this. For example, it’s important not to handle material more than once. If you let things slip, you can be out of business within weeks. So we place a great deal of emphasis on having

Seen here with the L350H in the background are (from left): Wikus de Winnaar, Mine Manager; Johan Vorster, Manager of Babcock’s Kimberley depot; and Schalk Steyn, founder and CEO of Steyn Diamante.

22  MODERN MINING  August 2018