OPERATIONS South Africa Region
|Mining method||South Deep is an underground bulk mechanised mine using a mix of full-time employees and contractors. Reserves are accessed through access development, destress and shadow development cuts to manage rock stress and seismic activity. A few selective mining methods, including drifts and benches, are employed but long-hole stoping with backfill is the primary bulk mining method. Given the unique mining method, there is a continuous extraction sequence and mine layout optimisation.|
|Mining operational infrastructure||
The workings are accessed from the surface through two shaft systems, the Twin Shaft Complex (main and ventilation shafts), of which the main shaft comprises a single drop to 110A level, a depth of 2,998m, the vent shaft to 110 level at a depth of 2,947m and the South Shaft Complex, which is a subvertical system (three operating shafts) to 95 level at a depth of 2,786m.
The mine is divided into three main areas:
|Mineral processing and TSFs||
The South Deep processing plant consists of a conventional SAG/ball milling circuit, a gravity gold recovery circuit and a conventional CIL/ CIP circuit. Final product from the gravity and CIP circuits is smelted into doré bars for refining at Rand Refinery.
For tailings retreatment, the South Deep plant also includes a tailings retreatment section that consists of a thickener followed by a dedicated CIL circuit.
South Deep has one active TSF, the Doornpoort TSF, and four dormant TSFs, known as TSFs 1, 2, 3 and 4. TSF 2 is undergoing remining using hydraulic mining methods. The top portion of TSF 1 has also been remined to date. TSFs 1 and 2 were commissioned in 1968 and operated as upstream raised paddock dams. These TSFs cover a combined footprint area of 69ha and have a maximum height of 47m. TSFs 3 and 4 were commissioned in 1982 and are also upstream raised paddock dams. These TSFs cover a combined footprint area of 100ha and have a maximum height of 41m. Deposition on these TSFs ceased in 2011.
The Doornpoort TSF was commissioned in April 2011 and three upstream wall raises have been constructed. The Doornpoort TSF incorporates a gravity decant system with drainage structures beneath the tailings. This facility has a remaining LOM storage capacity of ~149Mt (phase 2).