Modern Mining January 2019

DIAMONDS

production start of the K01 ore body in order to align with the improved open-pit depletion which allows us to reach steady-state produc- tion in 2024,” said Sahu. “This is a noteworthy achievement.” He noted that measures facilitating an advance of the original schedule include a raisebore shaft from the underground workings to serve the underground ore bodies, which will be piloted in 2019, as well as an incline from the ‘top of mine’ to the open pit, which is being driven upwards from underground. “These measures are temporary ground-handling solutions and are designed to maximise the optionality we have in bringing ore to surface during the transition period,” he explained. As is well known by now, a feature of the shaft sinking for the VUP is that Murray & Roberts Cementation is using – for the first time in Africa – its Canadian shaft-sinking method. The method – which involves the use of ‘sling down’ vertical drill rigs (VDRs) and verti- cal shaft muckers (VSMs) – is not necessarily faster than conventional South African-style shaft-sinking but is considered far safer as it eliminates concurrent activities on different working levels. It also reduces the number of people required to sink a shaft by around a third compared to the traditional method. Commenting on Murray & Roberts Cementa- tion’s experience with the method, Du Plessis said the company was more than satisfied with the results. “There was a bit of a learn- ing curve initially but we’ve now mastered the method and we’ve managed some very good rates of advance over the past year,” he said. “Murray & Roberts Cementation has taken the decision to only use the Canadian method in future. There’s no doubt that it is exceptionally safe and that very acceptable sinking rates are achievable.” From the point of view of WorleyParsons RSA, the VUP is a flagship mining project. The company was involved in the feasibility study and was subsequently commissioned to exe- cute the detailed engineering design for both the surface and underground infrastructure for the new underground mine. Its role further expanded with its appointment in 2016 as the EPCM contractor. A challenge for WorleyParsons RSA has been to ensure compliance not only with De Beers’ very demanding safety standards but also its policy of maximising local employ- ment opportunities and building capacity amongst emerging contractors and suppliers in the Venetia area. “We’ve had to assist with this process and also ensure that all contractors

reporting to us are aligned with De Beers’ poli- cies and vision,” said Greyling. Currently there are around 1 300 people working on the VUP but the peak is still ahead with the workforce predicted to number around 2 000 from late 2020 through till late 2021. Finally, and on the subject of automation, Sahu said that although De Beers would not be using any untested technologies in the Venetia underground mine, automation is being pur- sued intensively. “The mine will certainly be ultra-modern and incorporate best practice from around the world but the degree of automation is still to be determined – an autonomous truck- ing loop is a strong possibility – and we are currently engaging with market leaders on the solutions they are developing and can provide. “All our options are open as the mine design gives us a great deal of flexibility. The likeli- hood is that Venetia Underground will not be fully automated from day one but that it will become progressively more automated with time, as the technologies available from suppli- ers become more mature and well-established,” he concluded. „

The open pit at Venetia. The challenge for De Beers is to wind down open-pit operations and ramp up the VUP in such a way as to minimise the impact on the mine’s production profile.

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January 2019 _ MODERN MINING _ 47