Modern Mining: Featured News

With a new Engineering, Procurement and Construction Management (EPCM) project delivery model in place, the Venetia Underground Project (VUP) – the biggest single investment ever by De Beers in South Africa – is continuing to make excellent progress. Not only is it running on time and within budget but there are also options being considered that will accelerate production by at least a year. Modern Mining recently spoke to Christoff Kϋhn, Head of VUP, De Beers Consolidated Mines, and Robert Hull, Project Director for the EPCM contractor, WorleyParsons, to learn more about the current status of the US$2,1 billion project, which will extend the life of Venetia well into the 2040s.

By any measure, the VUP is a huge enterprise. It is certainly the biggest mining project currently under development in South Africa, and probably Africa as well, and the EPCM contract is the largest ever project award received by WorleyParsons RSA. In pure shaft-sinking terms, the VUP is also notable. It is one of only a handful of deep shaft complexes currently under construction worldwide and is also seeing the deployment for the first time in South Africa of a new
and safer shaft-sinking method originally pioneered in Canada.

Venetia Underground Project surges aheadThe portal of the new underground mine.

The VUP is a critical project for De Beers as it represents its future in South Africa. The only other South African operation, Voorspoed, is a much smaller mine and has a limited life of mine. Says Kühn: “By creating an underground mine beneath the current open pit, the VUP essentially doubles the life of Venetia and ensures that De Beers remains a major player in South African diamond mining for many years to come. Although the VUP can be seen as a life extension project, it can also be viewed as an expansion as the ore treated annually at Venetia will rise from approximately 5 Mt to 5,9 Mt. Over the life of mine, around 132 Mt of ore will be produced from two orebodies – K01 and K02 – yielding an estimated 94 million carats.”

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. To access the ore­bodies, two vertical shafts, 7 m in diameter each, are being sunk to a depth of 1 050 m, and a decline system for trackless equipment with a total length of 7 km is being developed. In all, the project involves the development of around 70 km of shafts, tunnels, chambers, workshops and water and ventilation systems – with this figure rising to just over 200 km over the life of mine.

Projects such as the VUP are a long time in the making. De Beers undertook the first concept study on the project in 2003, following up with a pre-feasibility in 2009/10 and a full feasibility in 2011. Board approval to proceed was given in late 2012 and the construction phase was launched in October 2013, when the first sod was turned on site.

WorleyParsons RSA has been involved continuously with the project since the pre-feasibility stage and was commissioned to execute the detailed engineering design for both the surface and underground infrastructure for the new underground mine. One of the innovations it introduced after starting the engineering design was the creation of a 3D model of the vertical shaft complex infrastructure that incorporates technical information of every component. Not only has the model shortened and de-risked the design process, but – once the underground mine is in production – it will give management a powerful tool that can be used for maintenance planning and control.

In October last year, the scope of Worley­Parsons RSA’s involvement was widened when it was awarded the EPCM contract. Commenting at the official signing of the contract, a senior spokesman for WorleyParsons RSA, said: “This contract is the result of the combined efforts from all parties who worked tirelessly for over a year to evolve the project into a different format. During our negotiations De Beers’ holding company, Anglo American, was in the process of changing its project execution synopsis, and this is the first contract signed globally in line with Anglo American’s new model.”

Explaining the scope of the contract, Robert Hull says that WorleyParsons’ responsibilities include project management, project accounting and project administration, project controls and document controls, engineering and design, procurement and materials management, construction management and quality management, as well as commissioning and operational readiness support. “This is a flagship contract for WorleyParsons and the first on this scale within WorleyParsons RSA,” he says. He adds that the contract covers all surface and underground infrastructure although the development and shaft sinking – but not the shaft equipping – is excluded.

WorleyParsons RSA is a ‘global centre of mining excellence’ within the wider WorleyParsons Group, which is a major international provider of project delivery, engineering and consulting services to the resources, infrastructure and energy sectors. The South African arm of the Group has huge experience of shaft projects and in recent years has been the EPCM contractor on the majority of the many shaft projects – most of them now complete – undertaken within the Southern African region, including Impala Platinum’s giant No 17 shaft.

As Project Director, Hull is based at the WorleyParsons RSA offices in Melrose Arch in Johannesburg but visits the Venetia site as required. A mining engineering graduate of the University of the Witwatersrand, he worked for De Beers earlier in his career before joining TWP (the predecessor company of WorleyParsons RSA) in 2007. After a stint as director and partner of a small mining consultancy, he re-joined WorleyParsons RSA in 2016 to deliver the Venetia project. He has been associated in many senior roles with some notable projects, including Wesizwe’s Bakubung platinum mine and the Harmony Newcrest JV’s Wafi-Golpu copper-gold project in Papua New Guinea.

According to Hull, WorleyParsons has a substantial team committed to the VUP. “The size of the team will vary as the project progresses but generally will be increasing from now through to 2018,” he says. “We have a team in Johannesburg and, at the site itself, we currently have a construction manager and certain other positions already in place and the number of personnel permanently based at the mine site will ramp up by up to 12 people by mid-2018.”

An interesting point is why De Beers has opted to move to an EPCM model after having managed the project directly for several years. “The short answer is that it is difficult for a mining company such as De Beers to establish its own in-house EPCM capability, particularly on a project of this scale,” Kühn responds. “One of the key challenges we had was establishing proper project controls and integrated systems. So we started talking to WorleyParsons and the result is the present EPCM arrangement, which gives us far more flexibility and which constitutes a very holistic approach. It is working extremely well and our forecasting and planning capability has significantly improved.”

According to Kühn, WorleyParsons RSA forms an integral part of the ‘tripartite alliance’ tasked with the delivery of the project. “The key players on the project are De Beers itself, of course, WorleyParsons RSA and Murray & Roberts Cementation, which is responsible for shaft sinking and the development of the decline system and related underground works. The alliance is working very effectively. We all work together as a team but we also have some very tough conversations – which is a sign of the mature relationship between the parties.”

Detailing the progress on the project, Kühn says that the sinking of the two vertical shafts is roughly at the half-way point, with the production shaft 40 or 50 m ahead of the service shaft. The decline system is also well advanced, with around 2,5 km of linear advance having been recorded (representing a vertical depth of approximately 500 m). “The decline has been a real success story. In 2016 we saw a 35 % improvement year on year in efficiencies and expect to achieve another 15 % this year, so the past two years have been characterised by significantly improved advance rates” he says. “As regards the new shaft-sinking method, our experience thus far has indicated that it is safer than traditional methods but not necessarily faster.”

Kühn believes there is every prospect that first production from the underground – presently scheduled for 2023 – could be brought back to 2021. “The good progress on the decline in particular is assisting us to look at potential opportunities to accelerate underground production.” He notes that with the underground mine starting just beneath the final depth of the open pit (approximately 450 m), safety considerations mean that there is little opportunity to overlap the final open-pit operations with the start-up of the underground mine. He adds that the project team, in conjunction with the mine management, is looking at measures to avoid a significant dip in production during the changeover.

Finally, Kühn makes the point that the VUP could be a pace-setter in terms of levels of mechanisation and automation. “An autonomous trucking loop – similar to the one that De Beers put in at Finsch when it still owned the mine – is the preferred option for Venetia,” he says. “Autonomous longhole drilling and autonomous LHDs are also part of the current plan. Our vision is for Venetia Underground to be a state-of-the-art mine that will set new standards in safety and production. We believe we are on course to achieve this goal.”

Report by Arthur Tassell, photos courtesy of De Beers

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Title: Editor
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Email: mining@crown.co.za
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Fax: +27 11 615-6108

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