Name: Bambanani mine.

Location: Bambanani is located 10 km south-east of Welkom, in the Free State, South Africa.

Controlling Company: Harmony Gold.

Brief Description: Bambanani has two surface shafts – East and West. The East shaft is bound to the west by Bambanani West shaft and to the north by President Steyn No 2 shaft.

Mining is conducted at a depth of 2 365 m. Activities at the mine focus on the Basal reef and are limited to shaft pillar extraction. The ore mined is sent to Harmony One Plant for processing.

Brief History: Anglo American Corporation started shaft sinking operations at President Steyn 4 shaft in February 1969. Sinking was completed in September 1971, at a final depth of 2 365 m below surface.

The Basal reef was intersected at a depth of 2 075 m yielding 1 252 cmg/t, or centimetre grams a tonne, over 235.7 cm. The subvertical shaft was sunk in the late 1970s to a depth of 3 328 m below surface. The subshaft came into production in 1982.

The shaft became known as Freegold 1 East in 1997, when President Steyn closed. In October 1998, the shaft became part of the then AngloGold and its name was changed to Bambanani East. In January 2002, the shaft was sold to the Harmony/African Rainbow Minerals consortium and, in October 2003, Harmony became the sole owner.

Products: Gold.

Geology/Mineralisation: The Basal reef is the main gold-bearing reef at Bambanani. The Steyn facies of the Basal reef covers about 90% of Bambanani’s mining lease area and overlays, with a very slight angular subconformity, the UF1 quartzite of the Welkom formation.

It is overlain by the Khaki shale unit of the Harmony formation in the north, but to the south it is overlain by the younger Waxy-Brown Leader quartzite that erodes the Khaki shale. Decisions to undercut the Basal reef may be influenced by the presence and thickness of the Khaki shale. Thickness of the reef may vary from a few centimetres to more than 10 m, but it is typically between 1 m and 3 m thick.

The Stuirmanspan fault in the west and the De Bron-Vermeulenskraal fault system in the east, bound the Basal reef at Bambanani mine. Both are northward-striking dextral extensional faults, with significant westerly downthrows. The reef dips easterly and varies from 25˚ in the west to 45˚ in the east, which can lead to vertical reefs in places.

Smaller faults break up the reef but are generally subparallel to the main structures.

Reserves: Total proven and probable reserves as at June 30, 2017, were estimated at 1.1-million tonnes grading 11.54 g/t gold.

Resources: Total mineral resources as at June 30, 2017, were estimated at 900 000 t grading 15.5 g/t gold.

Mining Method: Bambanani is in the final stages of its life-of-mine and mining is limited to the extraction of the shaft pillar.

Major Infrastructure and Equipment: Work is continuing in the shaft pillar on levels 66, 69, 71 and 73. Ore is transported by using a decline system, stretching from 58 to 75 levels, situated on the northern side of the shaft pillar, to West mine, where hoisting takes place. The linking level is the 60 level, where cross tramming is undertaken.

Bambanani does not have its own mineral processing plant and the mine’s ore is transported by rail for 7 km to the Harmony 1 plant for processing. This is a centrally located plant that is used by other Harmony mines in the Free State.

Prospects: Given the high risk of seismicity at Bambanani, efforts are focused on managing support systems and the rehabilitation of areas with challenging ground conditions.

Contact Details:
Harmony Gold
Tel +27 11 411 2000
Fax +27 11 692 3879
Email HarmonyIR@harmony.co.za
Website https://www.harmony.co.za