Modern Mining February 2018

DIAMONDS

After a slowish start, the US$2,1 billion Venetia Underground Project (VUP) of De Beers Consolidated Mines (DBCM) – the South African arm of the De Beers Group – is now running slightly ahead of schedule and well within budget. In an interview with Modern Mining’s Arthur Tassell at the Mining Indaba in Cape Town, DBCM’s Chief Executive, Phillip Barton, said that rates of advance on the decline system and the vertical shafts had improved significantly since the start of the project. Venetia project picks up pace

T he VUP is key to De Beers’ future in South Africa as Venetia will soon – once the Voorspoed mine in the Free State is sold – be the only De Beers mine left in the coun- try. As is now well known, the VUP will extend Venetia’s life until 2045 while allowing annual production to be maintained at roughly the current level of 4,5 million carats a year. “When the VUP kicked off in 2013, progress on the decline was slow, with only 50 to 60 m of advance per month being achieved,” says Barton. “Since those early days, rates of advance have been steadily increasing, first doubling and now tripling. In January this year, we achieved 188 m which is abso- lutely world class.” Improvements on the vertical shafts have been less dramatic but still noteworthy. “The shaft-sinking teams were struggling to do 30 m a month per shaft when the main sinking phase started,” states Barton. “Now they’re consis- tently achieving 40 m or more a month and 50 m a month is in sight.” The two shafts, which are being sunk to a depth of just over a kilometre, have both passed the 600 m mark and are on course to reach their full depth in 2019. To sink the shafts, the con- tractor, Murray & Roberts Cementation, is using its Canadian shaft-sinking system for the first time in Africa. Comments Barton: “The system has no cost advantage over conventional shaft-sinking methods but it is inherently safer as it elimi- nates concurrent activities and this was a critical consideration for us. Being a new meth- odology, there has inevitably been a learning curve but the teams have now mastered the equipment and techniques required and have developed a steady rhythm. We need to sink at a rate of at least 30 m a month and we’re comfort- ably exceeding this. We’re certainly not looking to break any shaft-sinking records – we’d rather

be on time and safe than way ahead of schedule but with safety perhaps compromised.” The VUP is being executed by a ‘tripartite alliance’ consisting of De Beers and the two main contractors on the project, WorleyParsons RSA, which has the EPCM role, and Murray & Roberts Cementation. “The alliance is work- ing well,” says Barton. “It took some time to bed down but we can now see it has matured. Everyone is totally committed to making a suc- cess of the project and the team has a good track record of coming up with ideas that have helped us in terms of time and cost – among other things, we’ll now be getting access to underground ore in 2021 which is considerably earlier than originally anticipated.” Barton acknowledges that the extended transition from the open pits to the VUP will inevitably have some impact on Venetia’s production, despite a number of mitigation measures that have been taken. “We’re expect- ing to see a fairly steep dip in 2019, which could see production decline to about 2,5 million carats. This is significant for DBCM but small when viewed from a De Beers Group perspec- tive, as our global production is now running at over 30 million carats annually. We’ll see a second, but much smaller dip, in 2023, when we transition from the K1 pit to underground.” On the subject of mechanisation and auto- mation, Barton says that Venetia Underground will be a state-of-the-art mine and will almost certainly incorporate automated trucking loops – which De Beers introduced at Finsch over a decade ago. “We’ll be building on this experi- ence at Venetia and will opt for autonomous mining wherever we think it is appropriate. Having said this, we’re not going to be pio- neers. Venetia is too important to the Group for us to implement anything that is untried and untested,” he explains. “The great thing is that autonomous min- ing technology is getting better all the time and we still have at least a couple of years before we have to make final decisions on the degree of automation we adopt. In addition, we’ve

Phillip Barton, Chief Executive of DBCM.

34  MODERN MINING  January 2018