South Africa region - Asset fundamentals


South Deep
General location   South Deep gold mine is situated in the magisterial districts of Westonaria and Vanderbijlpark (Gauteng province), some 45km south-west of Johannesburg at latitude 26º 25’ S, longitude 27º 40’ E. It is accessed via the N12 provincial road between Johannesburg and Potchefstroom.
Climate   The regional climate is classified as Cwb (warm temperature; winter dry; warm summer) under the Köppen-Geiger climate classification.
Licence status and holdings   South Deep converted its mining right (old order) to new order mining rights on 13 July 2010, as required by the Mineral and Petroleum Resources Development Act 28 of 2002 (as amended). The new order mining rights have been granted in respect of the mining area totalling 4,268ha (including the area known as Uncle Harry’s).
Operational infrastructure and mineral processing  

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 2,998 metres, the vent shaft to 110 level (2,947m) and the South Shaft Complex, which is a sub-vertical system (three operating shafts) to 95 level at a depth of 2,786m.

The mine is divided into three main areas:

  1. Current Mine, characterised by selective mining methods scattered over a large area originally exploited by means of conventional tabular mining. Current Mine is accessed from three active levels (90, 93 and 95) from both the South Shaft and Twin Shaft complexes.
  2. The North of Wrench (NoW) area, directly south of Current Mine comprises six mining corridors separated by regional pillars that extend southwards to the Wrench fault. A bulk non-selective mining method is applied here resulting in a higher Resource to Reserve conversion ratio.
  3. South of Wrench (SoW) East and West, situated south of NoW, which will be mined in the same manner as NoW.

South Deep gold mine operates one on-property gold plant. The comminution circuit comprises two stage milling with a free gold recovery circuit and gold recovery is carried out using a conventional leach/carbon-in-pulp (CIP) circuit. Final product from both the free gold and CIP circuits is smelted into bullion.

Tailings storage facility   South Deep utilises one tailings storage facility (TSF) known as the Doornpoort TSF. The TSF footprint is designed to accommodate the life-of-mine tonnage after backfill. The first phase of the dam was completed in 2011 and the top of the starter wall has been reached with the first wall raise completed in January 2018. Based on the current LoM plan the Phase 2 TSF infrastructure expansion will be required in 2020.
Mineralisation characteristics  
  1. Mineralisation hosted by conglomerates (reefs);
  2. Laterally continuous with long-range predictability;
  3. Clear patterns of predictable mineralisation governed by sedimentary characteristics; and
  4. Ore body definition and resource modelling programmes are ongoing.
Local geology and deposit type  

The reef horizons exploited in the South Deep LoM include the Ventersdorp Contact Reef (VCR) and the Upper Elsburg formation conglomerates. In the western half of the mining lease area the VCR occurs as a single reef horizon that overlies footwall lithologies of the Turffontein Subgroup. The Upper Elsburg reefs, subcropping below the VCR in a north-northeast trend, comprise multiple stacked reef horizons forming an easterly-divergent clastic wedge as illustrated in the schematic section opposite.

This wedge attains a thickness of approximately 120 to 130 metres in the vicinity of the eastern boundary of the mining right area. The Upper Elsburg Reefs constitute ~99% of the South Deep Mineral Reserve ounces, while the VCR makes up the remaining ~1%.

LoM   It is estimated that the current Mineral Reserves will be depleted in 2095 (78 years).
Social licence to operate  

South Deep reports its level of compliance in respect of its Social and Labour Plan (SLP) and Mining Charter commitments, on an annual basis. Furthermore, during Q4 2017, a compliance inspection was conducted by the Department of Mineral Resources (DMR) on the title conditions contained in South Deep’s new order mining right. No material issues were noted and South Deep has not received any formal communication from the DMR on the outcome of the review. The mine’s current SLP period has come to an end, and in December the next five-year SLP for the period 2018 to 2022 was submitted for approval to the DMR.

An amendment to the current approved water use licence was submitted during May 2015. Progress has been made in the processing of the amendment although approval is still pending. A consolidated Environmental Management Plan (EMP), current EMPs were approved in 2010 and 2012, was submitted for approval during Q4 2016, this is still under review by the DMR. The mine’s Safety and Environmental Management Systems are OHSAS 18001 and ISO14001:2015 certified. The mine is certified in compliance with the International Cyanide Management Code (ICMC).

Schematic west-east section through the South Deep ore body
West Wits line