Name and Location
Cullinan C-Cut Phase 1 expansion programme, Gauteng, South Africa.

Client
Petra Diamonds (74%), Thembinkosi Mining Investments (14%) and the Itumeleng Petra Diamonds Employee Share Trust (12%).

Project Description
The Cullinan mine contains a world-class resource base of 199.6-million carats, including 17-million carats in tailings. Petra plans to capitalise on this by undertaking an expansion programme to increase production to 2.2-million carats a year by the 2019 financial year, comprising two-million carats run-of-mine (RoM) and 200 000 ct of tailings.

C-Cut Phase 1 will establish a new block cave on the western side of the orebody, in the upper portion of the major C-Cut resource, which is estimated to contain 133-million carats, it will also involve a large tailings retreatment operation.

The development plan will allow for the tonnage profile to gradually switch from the old mining areas, heavily diluted with waste rock, to the new mining areas, thereby providing access to undiluted ore. As a result, the RoM grade is expected to increase in future years from about 26 carats per hundred tonnes (cpht) to more than 50 cpht by the 2019 financial year, when the C-Cut Phase 1 block cave is in full production.

Petra’s current mine plan envisions a life-of-mine (LoM) to 2030, but the major residual resources at the mine indicate that the actual LoM could be more than 50 years.

Value
Not stated.

Duration
The plan is to increase production from 800 000 ct in the 2014 financial year to 2.2-million carats by the 2019 financial year.

Latest Developments
The underground project scope is 64% complete, which equates to about 2 km of development ahead of schedule.

Murray & Roberts Cementation has reported that mining/production build-up from C-Cut has started and that by year-end, the company will be in a position to deliver upfront tons.

To date, sinking and 3 Shaft has been completed and Murray & Roberts is working to complete the equipping and lining of the shaft shortly.

Sinking at 1 Shaft is also well advanced and will reach the loading box this month.

Raise boring has been used for both shafts – another project aspect that has ensured on-schedule development rates, as equipping and sinking can occur simultaneously.

Murray & Roberts has also started with the slipe and line for the two storage silos. It has also facilitated engineering for the Koepe winders – the first was completed in December 2015 and the second is due for completion in December 2015.

Key Contracts and Suppliers
Murray & Roberts Cementation (deepening of Shaft 1 and Shaft 3, as well as associated infrastructure and planned level development) and ABB (upgrade of the Koepe winder and ropes).

On Budget and on Time?
The project is on time and within budget.

Contact Details for Project Information
Petra Diamonds, email info@petradiamonds.com.
Murray & Roberts Cementation, tel +27 11 201 5000.
ABB (South Africa), tel +27 10 202 5000 or fax +27 11 579 8000.