Modern Mining January 2016

DIAMONDS

than conventional cactus grabs, at the same time providing far greater safety. The VSMs are also able to manoeuvre the kibbles – which can weigh a ton or more – into position, eliminating the potentially dangerous practice of handling them manually. Both the drill rigs and the VSMs being used at Venetia were originally developed by a Canadian company, MTI, now part of Joy Global. Each shaft at Venetia will be served by two sling-down rigs and two VSMs and these have already been delivered to site by Joy Global. A further VSM is in use at Bentley Park. Delivery of explosives has also changed in the new method, with pumpable bulk emul- sions being used – a more efficient way of charging holes than the stick-type explosives previously employed. It is expected that the

system,” he continues. “The facility repre- sents a major investment by Murray & Roberts Cementation but a very necessary one, as the intention is that all the company’s future shaft- sinking contracts – and not just Venetia – will be executed using the methodology.” In terms of equipment, the new system involves the use of ‘sling down’ jumbo drill rigs and vertical shaft muckers (VSMs) accommo- dated in the sinking stage. The sling-down rigs, apart from dramatically reducing the number of workers required on the shaft floor during drilling, offer greater drilling precision than the jumbo rigs used in the past. As for the VSMs, they are equipped with long, extendable booms with jaws on the end and are operated from the stage in a remote-controlled manner. They will clean the shaft floor faster and more effectively

The high-capacity batch plant serving both the verti- cal shafts and the decline. It has a capacity of 110 m 3 /h.

The Venetia site in October 2015, with headgear erec- tion at an advanced stage (photo: De Beers).

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