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Petra Diamonds' Cullinan c-cut Phase 1 Expansion Celebrates Signoficant Advancement Progress with Murray & Roberts Cementation
Sunday, 1 November 2015
The underground portion of the C-Cut Phase 1 Expansion project at Petra Diamonds’ Cullinan mine, initiated in 2011 and due for completion in 2019, has already been recognised as a major success. Shaft sinking specialist, Murray & Roberts Cementation believes that its dedication to its portion of the overall contract has helped position the project well ahead of schedule.
The expansion project is transforming Cullinan mine and will deliver a new operation which will outperform its last years of operational performance. “The new mine gives us access to greater volumes of fresh, high grade undiluted ore for at least another 16 years. It will also ensure the mine retains its status as one of Petra Diamonds’ flagship diamond mines well beyond 2016,” says Petra Diamonds mining projects manager, Andre Cloete.
The C-Cut Phase 1 Expansion project entails the development and construction of a new block cave on the western side of the ore body, 200 m below the current operational B block mining horizons, situated between 645 level and 885 level below surface.
Once in full production, the new C-Cut block will increase Cullinan’s Run-Of-Mine production from 2.5 Mtpa in FY 2015 to 4 Mtpa by FY 2019. By accessing the C-Cut block and mining high grade undiluted ore, ROM grades are set to increase from 24 cpht in FY 2015 to grades in excess of 50 cpht in FY 2019. As a result ROM carat production is expected to increase from 0.6 Mcts in FY 2015 to +2 Mctpa by FY 2019.
In addition to the upgrade and expansion of surface infrastructure, the expansion includes the deepening of both the men & material shaft (3 Shaft) from 805 level to 885 level and the rock hoisting shaft (1 Shaft) from 580 level to 934 level. It also includes new north and south decline declines and conveyors; heavy-duty, high volume north and south crushers; two big storage silos and the requisite access area development.
Murray & Roberts Cementation’s contract, awarded in August 2012, includes the shaft sinking extensions for both 1 and 3 Shaft. The company believes that its contribution towards the project’s success continues to play a pivotal role in maintaining the development schedule but more importantly, moving ahead of it.
The actual underground project scope is 64% complete and to date equates to about 2 km of development ahead of the original targets Cloete notes. “Mining/production build-up from the C –Cut has in fact already started and by year-end we will be in a position to deliver upfront tons.”
The project manager notes that the Murray & Roberts Cementation sinking team is particularly effective with time utilisation. “We have focused intensively and simultaneously on all project aspects and variables as well as upfront scheduling which utilises our 307 employees’ time effectively. This has minimised delays resulting from unforeseen sinking challenges for example,” Robbie Duyts, Murray & Roberts Cementation’s senior project manager explains.
“The Cullinan team’s combined shaft sinking experience has also played a major role in ensuring this project continues to advance smoothly.”
To date, sinking at 3 Shaft (7 m diameter / 6 m diameter lined) has been completed and Murray & Roberts Cementation is working to complete equipping and lining shortly. Sinking at 1 Shaft (9.6 m x 2.3 m lined) is also well advanced and Duyts notes that sinking will reach the loading box by December this year. The raiseboring technique has been used for both shafts – another project aspect which has ensured on-schedule development rates as equipping and sinking can occur simultaneously.
In addition to the shaft sinking contract, Murray & Roberts Cementation has also started with the slipe and line for the two storage silos (13 m x 36 m). It has also facilitated engineering for the Koepe winders – the first was completed in December 2014 and the second is due for completion in December 2015.