Modern Mining January 2016

DIAMONDS

the blast cover effectively prevented fly rock from leaving the shaft barrel when the blast was set off. In contrast to the vertical shafts, the 6 x 5 m decline is being developed using standard methods. “The decline – which, like the shafts, is being excavated through very com- petent rock – has thus far progressed smoothly and we’re now 1,2 km in from the portal,” Chamberlain observes. “We have, incidentally, adopted our Australian sister company’s pol- icy of using highly-skilled machine operators and we’ve had Australian coaches over here to assist with training. Part of this training takes place at Bentley Park and the machine simula- tors we’ve installed there are bench-marked to Australian standards.” The primary mining fleet deployed for the decline comprises Sandvik machines. Two Sandvik DD421 twin boom electro-hydrau- lic jumbos are used for drilling the face and for rock support and work in conjunction with Sandvik LH514 LHDs and Sandvik 40-t capacity underground haul trucks. The aux- iliary equipment fleet – for example, utility vehicles, concrete mixers and shotcreters – includes machines from Getman and Normet. All the equipment is owned by De Beers but operated and maintained by Murray & Roberts Cementation. Reviewing the progress thus far on the con- tract and the road ahead, Christoff Kühn says that the VUP is currently on schedule and within budget. “We’re pleased at the way the project is unfolding. Soon we will be in the full sink mode which will continue through to 2018 when both shafts will have reached their final depth, when the focus will move to equipping the shafts and lateral development,” he says. “By 2021 – when the open pit will have reached its final depth of approximately 450 m – we will be commissioning the new mine and potentially this will be one of the most challenging parts of the project, as there

is very limited opportunity to overlap open-pit operations with the start-up of the underground mine. All the options for the transition are cur- rently under intensive study with a view to avoiding a significant dip in production during the change-over.” Finally, an interesting point is whether the underground mine currently being developed will be the final phase of Venetia. The kimber- lite resource extends well below the maximum depth of mining allowed for in the VUP and there is therefore a clear possibility that the mine life could be extended even further. Comments Kühn: “Obviously this is a decision which is years away and which will be taken by the De Beers board and its shareholders at the appropriate time in the light of market conditions and other relevant factors. What I can say with confidence, however, is the mine we are currently creating will be a world-class operation which assures De Beers’ future in South Africa for years to come and will pro- duce diamonds for our grandchildren besides, if necessary, providing the platform for a fur- ther extension of Venetia’s life beyond what is currently envisaged.” Photos by Arthur Tassell (unless otherwise acknowledged)

One of the winders being used in the sinking of the production shaft. The permanent winders for the project – two ground- mounted Koepe winders for the production shaft and a double-drumwinder and a single-drumwinder for the service shaft – have been ordered from ABB.

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January 2016  MODERN MINING  53