Modern Mining: Featured News

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.

           The headgears of the Venetia Underground Project (VUP).

The 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 country. 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 absolutely 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 consistently 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 contractor, 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 eliminates concurrent activities and this was a critical consideration for us. Being a new methodology, 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 comfortably 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 working 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 success 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 expecting 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 perspective, 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 automation, 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 experience at Venetia and will opt for autonomous mining wherever we think it is appropriate. Having said this, we’re not going to be pioneers. 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 mining 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 built in a high degree of flexibility to the mine design. For example, the VUP has a ventilation system that caters for diesel-driven equipment and an electrical system that caters for electrically-driven equipment, which gives us a great deal of optionality.”

While the VUP secures Venetia’s future until 2045, Barton believes that the mine could operate for even longer. “I would say that a further extension of life is almost a given. We’ll be mining the larger K1 ore body to just short of a kilometre and the K2 kimberlite to approximately 670 m. There’s definitely potential to go deeper on both these ore bodies,” he states.

“Kimberlite is not competent rock and the rule of thumb has always been that a kilometre is about as far down as one wants to go – which is the depth we mined to at Wesselton in Kimberley, which was the deepest diamond mine in the world when it closed in 2005. But there’s no real reason we can’t go deeper – particularly when you consider that by the 2040s mining methods and technology will have advanced considerably from where they are today. Certainly, we have ‘blue sky’ scenarios that suggest that Venetia could still be going in 2060.”

On the all-important issue of safety, Barton notes that DBCM has made huge strides in recent years. “Our last fatality was at Finsch in 2008, when the mine was still part of our stable. So we’re heading for 10 years without a fatality within DBCM. Our last Lost-Time Injury (LTI) at our Voorspoed mine was in October 2014. Regrettably, Venetia has not done quite as well and we’ve had 10 LTIs at the mine over the past two years, nine of these in the shafts and none of them involving DBCM employees. The question we’ve asked ourselves is ‘why are our contractors having LTIs?’ There has been intense discussion around this and we’re working very closely with our contractors to rectify the situation.”

On the plus side, the production shaft of the VUP has now gone 18 months without an LTI and the decline more than four years. “The record of the team on the decline is particularly impressive, if you consider that more than 3,5 km of development has been completed,” Barton points out.

Moving on from the VUP and safety, Barton says that the sale process for the Voorspoed mine is going well. “The interest has been greater than we expected,” he states. “Of course, not all the interested parties will necessarily meet the requirements we’ve set down. We will only consider bidders who have access to sufficient capital, impeccable BEE credentials (and the more broad-based, the better), the requisite mining skills and a value-set which is in alignment with the values of the De Beers Group. These requirements will no doubt rule out quite a few parties but we’re nevertheless confident that we will be able to announce a successful bidder in May this year.”

Barton adds that Voorspoed is a quality asset, albeit one with a limited remaining life. “Our belief is that the right player can probably do another ‘half cut’ on the open pit which will allow mining to continue till at least around 2024. Certainly, there is some good money still to be made,” he observes.

Finally, what of the future for DBCM in South Africa – is it likely to continue as essentially a single-mine operation or is there a reasonable prospect that it could develop new mines? “We would definitely like to have more than one producing asset,” Barton responds. “It’s therefore very good news that we’re finally getting movement on our exploration licence applications after a long two-year period when we seemed to be getting nowhere. We’ve now had 16 of the more than 50 applications we’ve submitted approved and we’re hopeful that others will follow soon. All those granted thus far are in the Northern Cape, specifically the Kimberley area, but we’re also targeting ground in the Free State, North West and Limpopo provinces.

“With our new permits in place, we’re preparing to launch a new and intensive programme of exploration in South Africa after a long hiatus. Any new discoveries are likely to be under relatively deep cover but our exploration technologies are now very sophisticated – if the kimberlites are there, we have a good chance of finding them. There are obviously no guarantees but we’re optimistic that our exploration efforts might eventually deliver one or more new mines.”

Contact Modern Mining

Title: Editor
Name: Arthur Tassell
Email: mining@crown.co.za
Phone: +27 11 622-4770
Fax: +27 11 615-6108

Title: Advertising Manager
Name: Bennie Venter
Email: benniev@crown.co.za
Phone: +27 11 622-4770
Fax: +27 11 615-6108

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