Modern Mining January 2016

DIAMONDS

surface. In addition, the company will under- take horizontal tunnel development to access and establish the two caves and provide associ- ated infrastructure, including two large crusher chambers near shaft bottom. According to Graham Chamberlain, Project Executive with Murray & Roberts Cementation, the VUP also marks a watershed inasmuch as it is the first project where the Canadian shaft- sinking methodology is being adopted in its entirety. “We have deployed aspects of the system on some of our other current or recent projects but the VUP will see it being used from start to fin- ish in a systematic manner,” he says. “The main motivation for adopting the method is its inher- ent safety as all activities in the shaft-sinking cycle now occur sequentially. At no point do you have personnel working simultaneously at different levels within the shaft – as you do with conventional techniques – with all the safety risks that this brings and there are fewer people working in the shaft barrel at any one time. Teams are multi-skilled and perform all required tasks. This compares to the old sys- tem where you had one crew to drill, another to lash, a third to support and so on. Now we use a single ‘super-crew’. “To develop the necessary skills here in South Africa, we’ve built shaft mock-ups at our Bentley Park training academy near Carletonville on the West Rand where trainees are given total exposure to both the techniques and equipment – and, importantly, the ‘mind- set’ – required to implement the Canadian

modification and expansion of the plant will be required but the capex involved is minimal.” The underground resource will be mined by means of the Sub Level Caving (SLC) mining method in the case of the bigger K01 orebody with a modified SLC system being used for K02. The K01 cave will produce 4 Mt/a and the K02 cave 1,9 Mt/a. “The mining methods are conventional and well proven, so there’s no pioneering involved,” says Kühn. “What could, however, be unusual is the possible use of an automated trucking loop on the lines of what De Beers put in at the Finsch mine in the Northern Cape roughly ten years ago when it owned the operation. We’re already in preliminary dis- cussions with a couple of the OEMs on this, although it must be stressed that at this stage the use of driverless trucks is no more than a possibility.” He adds that semi-automated drill- ing is also under consideration. While a project the size of the VUP will typically have many different contractors, sub- contractors and suppliers involved, Murray & Roberts Cementation is handling the lion’s share of the work. “Essentially, they’re respon- sible for delivering the project to De Beers in terms of the shafts and underground infrastruc- ture required,” Kühn says. Elaborating, he notes that Murray & Roberts Cementation is responsible for the two vertical shafts the project requires, both 7 m in diameter and 1 080 m deep, one a production shaft and the other a service shaft, as well as a decline for trackless equipment which will ultimately be 7 km long and provide access to 900 m below

The portal of the decline. Ultimately the decline will have a length of 7 km.

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48  MODERN MINING  January 2016