Mechanised development drilling
at South Deep

Latest statistics reveal that the company’s annual gold production is currently more than 4.1 million ounces, its ore reserves have reached almost 93.8 million ounces, and its mineral resource figure stands at 251.7 million ounces.

Executive vice president and head of South African operations, Terence Goodlace, confirms that a breakdown of the company’s four main local operations for F2007 shows that Driefontein produced just over 1 million ounces, Kloof topped 920 000 ounces, and Beatrix was close to 550 000 ounces, while South Deep produced 163 000 ounces since its acquisition.


The South Deep twin shafts at dusk

In an exclusive interview with Mining Review Africa, he predicts that Driefontein and Kloof should maintain their current production levels this year. “And while Beatrix is likely to show a slight reduction,” he adds, “South Deep should produce 320 000 ounces this year, and should ramp up by more than 25% in F2008 reaching a level in excess of 400 000 ounces.”

As far as capital investment spending is concerned, by far the greatest contribution revolves around South Deep, which is one of the most important developing gold mines in the world, with reserves of 29.3 million ounces contained in a resource of 67 million ounces.

“The eventual total paid for South Deep amounted to R22.2 billion, with R8.3 billion going to Barrick, R2.9 billion to Barrick Gold Africa, R7.1 billion to Western Areas, and R3.9 billion to settle the Hedge,” reveals Goodlace


Loco drill rig in use at Kloof gold
mine to improve development

“Added to this,” he says, “the capital being spent on Phase One for the first five years will show a 23% increase from the R3.5 billion estimated in January 2006 to a current revised level of R4.3 billion.” There are four main reasons for the escalation:

  • The cost of development below 95 Level has risen more than 50% from R1.347 billion to R2.044 billion for a 32 km section, due mainly to escalation and new contractor rates. The development project below 95 Level entails developing the 100, 105 and 110 levels to reef with access by twin intake haulages and return airway with conveyors for ore return to the shaft hoisting facilities. “The contract has been awarded to Murray and Roberts, which is already mobilising,” says Goodlace. “The forecast development contract or value could amount to approximately R1 billion over the five-year period”
  • Expenditure on the ventilation shaft deepening project is up more than 12.5% from R586 million to R660 million. This project has been underway since January 2006, and the estimates are based on contracts in place. This project involves installing a brattice wall in the ventilation shaft and deepening the shaft by 241m to 3 005m below surface. The shaft will then be equipped for rock hoisting, and a Blair Multi Rope rock winder identical to the one in Main Shaft will be installed and commissioned. Installation of the brattice wall is planned for commissioning by January 2008, and is critical for the commissioning of the 94 Level refrigeration plants. The shaft will then be equipped with permanent services and steelwork from February through to November 2008, when shaft deepening begins. This blind sink for 241m is scheduled for completion by February 2010
  • Costs of the refrigeration plant on 94 Level have risen 25% from R130 to R163 million, again due to escalation and revised contracts. This project started at the beginning of 2006, and is on track for commissioning and operation by the end of 2007. It will assist significantly in achieving the mine design of 28.5 degrees Celsius in reject wet bulb environmental conditions. The surface main ventilation fans are commissioned with the completion of the brattice wall and surface duct, and significant chilled water piping is installed to commission bulk air coolers in each of the mechanised projects. The major construction and procurement contracts for this phase are in place
  • A surface exploration project has been introduced for 11 surface boreholes at a cost of R131 million.

Geologists Khaya Sibeko and
Hemla Reddy inspecting core
at surface drill rig KEA 4
in the Kloof extension area

To date the Gold Fields board has approved these four sub-projects, which amount to almost R3 billion of the total R4.3 billion which will be required. Still to come are the plant upgrade and backfill and tailings facilities, which will make up the balance of R1.3 billion.

“Phase One – which commenced in January 2007 – is scheduled by 2012 to complete the infrastructure required to expand production from 220 000 tonnes milled to 330 000 tonnes,” Goodlace continues. “At this point underground production would be sustained at this level, with the balance of Phase One capital expenditure taking place between 2013 and 2020,” he adds.

“Phase Two (the future mine) would require additional capital expenditure to sustain the milling rate of 330 000 tonnes per month, and a production level of 800 000 ounces per annum,” he points out. Goodlace explains that there are no further details available at this stage. “That phase goes beyond 2020, and forms the basis of the Kloof / South Deep Optimisation Projects, (KSDO projects),” he says.

Terence Goodlace

Gold Fields executive vice
president and head of
South African operations
Terence Goodlace

Goodlace confirms that Gold Fields is looking at the feasibility of combining the operations of South Deep and Kloof. “We have developed six scenarios out of an original 64 options,” he reveals, “and these are what we call the KSDO projects. Four of them involve linking the two mines underground and using the Kloof infrastructure to process about 150 000 tonnes per month of ore from Phase Two of South Deep. Two of the scenarios assess the two mining operations as separate entities,” he adds.

Preliminary details of the study have been released at this stage, but the intention is to announce the results by the end of the year. “We will select the best of the six scenarios and should move straight into a pre-feasibility study,” Goodlace reveals.

Cost of the shaft deepening project at Driefontein – originally estimated at R3.3 billion – will now rise by almost 25% to R.4.1 billion. “A change of scope has been carried out to minimise project timing and technical risk,” he explains.

The change of scope adds an additional R844 million to:

  • Sink a sub-vertical ventilation shaft to mitigate the risk of the raise boreholes in proximity of the Spotted Dick (water-bearing) Dyke; and
  • Provide additional capital for seven-day sinking costs to mitigate changes in methodology and to complete the shaft barrel infrastructure.

Number Four shaft at Kloof
gold mine

In essence, four ventilation raise-bored holes are being replaced by a single, conventionally-sunk ventilation shaft. “The depth – from 3 083m to a final level of 4 121m – makes it (to my knowledge) one of the deepest shaft systems in the world,” Goodlace contends.

“The project sink is scheduled to kick off in November 2007,” he reveals, “and original estimates are that sub-vertical ventilation shaft sinking will be completed by August 2011, and equipping will begin in September and end by June 2013,” he calculates.

“With the change of scope the top four levels will be developed via the sub-ventilation shaft, and this is planned to commence in January 2013 through to May 2015,” says Goodlace. He estimates that the bottom three levels will start in July 2013, and intersect the reef in October 2015. Planned full production of 170 000 tonnes per month is scheduled to be achieved by 2019.

The current reserve for this project is 31.1million tonnes at a head grade of 8.5 g/t, and delivered gold of almost 8.5 million ounces. The resource stands at 36.6 million tonnes at a mined grade of 11.8 g/t and in situ gold of 13.9 million ounces. Life of mine will extend to 2036.


Number Nine shaft at Driefontein
gold mine

The planned R1.4 billion project to develop a decline shaft system to provide access to the Kloof Extension Area (KEA) has been put on hold.

“There are two main reasons for stopping the project,” Goodlace explains. “First, we are evaluating the KSDO options, as mentioned earlier – one must bear in mind that the mine’s Four Shaft, the KEA project and South Deep Phase 2 are inter-dependent,” he emphasises.

“Second, we are awaiting the results of a surface drilling campaign which should be completed by the end of 2007,” he continues. “There have been indications that there is less ore body continuity, and that the project might have to be re-scoped. We will provide an update on this project once all the drilling and the KSDO scoping project have been completed,” Goodlace concludes.