Name and Location
South Deep gold mine expansion, Gauteng, South Africa.

Client
Gold Fields.

Project Description
South Deep is a fully mechanised underground mine, extracting a wide multiple band reef at depths of between 2 000 m and 3 000 m below surface. The extraction of such deep-level, wide reefs have not been totally mechanised elsewhere in the world. The production methods used at the mine are, therefore, unique and differ markedly from the labour-intensive mining method traditionally applied in underground mines in South Africa.

The project comprises a main shaft and a ventilation shaft – collectively referred to as the Twin Shaft complex, which will have a combined hoisting capacity of 370 000 t/m of ore.

The main shaft was completed in 2004 and comprises a single drop to a depth of 2 995 m.

The ventilation shaft has been deepened from 2 760 m to about 2 950 m and is fully equipped with ore-storage silos and conveyor belts at shaft bottom, a new rock winder and new headgear.

The mine’s headgear at the vent shaft was completed in 2011 using one of the largest fabricated steel headgear frames in the world.

The South Deep metallurgical plant, which was commissioned in November 2012, has also been expanded and has increased processing capacity from 220 000 t/m to 330 000 t/m.

From 2010 to 2012, the mine completed the construction of the centralised tailings storage facility, developed and installed infrastructure around the shaft systems and also changed to full plant tailings backfill for increased production levels. The backfill plant was commissioned in early 2012.

The South Shaft complex will add an additional 120 000 t/m of hoisting capacity to the mine, bringing the total combined hoisting capacity to 450 000 t/m.

The South Deep operation had a mineral resource of 70-million ounces as at December 31, 2013, and a mineral reserve of 35.1-million ascertained ounces, which will give the operation a life-of-mine until about 2087.

Value
An estimated $4-billion has been invested to date.

Duration
A timeline for the roll-out to steady-state production is still being developed.

Latest Developments
Gold Fields has adopted a strategic mine design change in the distress methodology, with a detailed transition programme developed to guide the change process.

The conversion from low-profile (2.5 m vertical height) to high-profile (5 m vertical height) started in the quarter ended September 30, 2015, and is expected to simplify and derisk the mining process. The transition to high-profile distress is expected to continue until early 2017.

In the quarter ended September 30, several important activities at the mine, had progressed including:
• Development increased 58%, from 939 m in the June quarter to 1 486 m in the September quarter, which included 347 m of new mine development (Phase 1, sub-95 level), an increase from 83 m in the June quarter.
• distress mining increased from 6 056 m2 in the June quarter to 9 523 m2 in the September quarter, which was attributed to stress mining is attributed to the commissioning of the new low-profile fleet, improved mining cycles and the introduction of a dedicated supervision per activity per corridor.
• Total reef tonnes broken increased 37% to 333 000 t. Longhole stoping accounted for 40% of total ore tonnes mined, compared with 37% in the June quarter.
• Secondary support improved by 14% during the September quarter to 1 584 m, while backfill cubes increased by 42% from 79 m3 in the June quarter to 113 m3 in the September quarter.
• Twenty out of the 27 new category 1 equipment bought during the year was commissioned by the end of the September quarter. The renaming of seven category 1 units are expected to be commissioned by the end of 2015.

Production for the full year is expected to be between 5 900 kg and 6 000 kg, with the second half being up about 50% on the first half of the year. Gold Fields expects 2016 production to be significantly better than 2015.

Key Contracts and Suppliers
Redpath (backfill piping, battrice panel installation and replacing the South Shaft steelwork); Newrack (secondary support); TWP (metallurgical plant design); AEL Mining Services (supply of explosives for blasting) Atlas Copco and Sandvik (suppliers of HME and spares).

Previous contractors and suppliers:
Murray & Roberts Cementation (mine development and shaft deepening); Wilson Bayly Holmes-Ovcon (WBHO) and Wade Walker (tailings dam); MM&G (steelwork fabrication); Steel Services and Allied Industries, Hatch and Cadhouse Design Enterprises (ventilation shaft headgear); Howden Africa (commissioning of main surface-ventilation fans) and Sarens South Africa and Crane Corporation (overhead crane for the ventilation shaft headgear).

On Budget and on Time?
The project is on budget, but a timeline for the roll-out to steady-state production has not yet been determined.

Contact Details for Project Information
Gold Fields VP Corporate Affairs Sven Lunsche, tel +27 11 562 9763 or email media@goldfields.co.za.
Redpath, tel +27 11 974 2051.
TWP, tel +27 11 218 3000, fax +27 11 218 3100 or email twpinfo@twp.co.za.
AEL Mining Services, tel  +27 11 606 0000.
Atlas Copco, tel +27 11 821 9000.
Sandvik, tel +27 11 929 5300.

Previous contractors and suppliers:
Murray & Roberts Cementation, tel +27 11 201 5000.
MM&G, tel +27 11 914 4740.
Wade Walker, tel +27 11 466 0377.
WBHO, tel +27 11 321 7200, fax +27 11 887 4364 or email wbho@wbho.co.za.
Steel Services and Allied Industries, tel +27 18 787 2059 or fax +27 18 787 3416.
Hatch, tel +27 11 239 5300 or fax +27 11 239 5790.
Cadhouse Design Enterprises, tel + 27 16 429 1643 or email info@cadhouse.co.za.
Howden Africa, tel +27 11 240 4000, fax +27 11 493 0545 or email enquiries@howden.co.za.
Sarens South Africa, tel +27 11 861 3800, fax +27 11 861 3899 or email info@sarenssa.co.za.