Modern Mining September 2017

DIAMONDS

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 sys- tem 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 con- cept study on the project in 2003, following up with a pre-feasibility in 2009/10 and a full fea- sibility 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 infrastruc- ture for the new underground mine. One of the innovations it introduced after starting the engi- neering 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 Worley­ Parsons 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

Above: The portal of the new underground mine.

Left: A view of the Venetia mine with the headgears of the two new vertical shafts of the VUP on the skyline.

surges ahead 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 creat- ing 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 min- ing 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 and safer shaft-sinking method originally pio- neered in Canada.

September 2017  MODERN MINING  27