Goodlace says that all conventional mining has ceased and, in addition to the massive mining under way at South Deep, Gold Fields is also moving to something that is also new for the mine, namely mechanised destressed mining.

Goodlace says that massive mining is something new for the Wits deposits, other than the Target mine, in the Free State.

He says that South Deep has a shaft system all the way down to 3 000 m.

“It’s designed to be a modern mechanised mine,” he tells Mining Weekly.

“What you will see in the future is the use of highly mechanised equipment and not as many people exposed in the underground situation. If you were to take an analogy, look at any modern massive mining,” he adds.

Meanwhile, the rehabilitation of the primary support of ramps within South Deep will be completed by the end of August.

As a result of the depletion of the Ventersorp contact reef and the cessation of conventional distressed mining, Gold Fields operational head Vishnu Pillay says that 1 700 South Deep employees have accepted voluntary retrenchment in the last two months and the mine is in the process of looking at voluntary retrenchment for another 350.

South Deep formerly had a staff complement of 4 300 people and 1 200 contractors, and is expected to have a final complement of 2 200 people. With the 1 200 contractors, it will leave the operation with a staff complement of some 3 400 people.

Some R70-million has been set aside for the payment of voluntary retrenchment.

Kloof Shaft Rebuild

As part of Gold Fields’ heightened safety awareness, infrastructure is being scrutinised across the operations.

What was identified during this period is that the Kloof main shaft steelwork is in urgent need of rehabilitation.

The area worst affected is below 17 level.

“Simply put, we have had to stop that shaft and do this work, which is going to take about six months,” says new Gold Fields CEO Nick Holland.

“Unfortunately, that is one of the main shafts where we hoist about 60% of our gold and we are putting contingency plans in place to deal with that.

“I don’t want to delay these kinds of issues and that is why I have taken these very hard decisions, but the right decisions, and we have to stop that shaft,” he said, involv- ing a loss of 500 kg a month for six months.

“The situation is such that we have this 40-year-old shaft. It has got significant corrosion below 17 level,” says Goodlace.

A large quantity of steel will be requi- red and steel bunton sets have to be replaced.

Engineering and procurement for the repair programme have still to be carried out.

The mine needs to be kept going simultaneously, requiring a significant change of logistics and ore flows.

One of the critical aspects is to take the 3 000 people who currently use the shaft down one of the other shafts.

The transfer of people between shafts will take place on the platform level of Kloof’s 23 level.

Driefontein Support

Steps are being taken to improve secondary support at Driefontein, which means that the gold mine’s production will be reduced by 400 kg in the next quarter as high-grade areas are upgraded.

“Secondary support has been a problem for years and we have taken the view that we cannot continue with it,” says Holland.

Holland expects Driefontein to be over the worst of that in the December quarter and back up to the targeted 6,8 t of gold a quarter.

Goodlace says that it is critical to ensure that haulages can withstand seismicity and depth in deep-level mines.

“We are mining down to 3 500 m below surface and we need to make sure that we keep all of our haulages open,” Goodlace points out.

This entails going over and above the primary support patterns and installing secondary support tendons, lacing, meshing and shotcreting of those haulages.

“We aim to eliminate the backlog over the next six to nine months,” he says.

Greater Safety

The overall aim of the Driefontein secondary support programme, the Kloof main shaft rebuild, the pillar and remnant mining review and the rehabilitation of South Deep ramps is to bring about a safety step change.

“Safety is an absolute imperative. That’s what has to come first, and we are putting our money where our mouth is,” says Goodlace, who leaves the organisation at the end of September.

To subscribe to Mining Weekly's print magazine email subscriptions@creamermedia.co.za or buy now.