Name: Kusasalethu mine.

Location: Kusasalethu is situated 14 km south of Carletonville and 90 km south-west of Johannesburg, in Gauteng, South Africa.

Controlling Company: Harmony Gold Mining Company.

Brief Description: Kusasalethu comprises twin vertical and twin subvertical shaft systems, and uses conventional mining methods in a sequential grid layout. Mining is conducted to a depth of 3 388 m, making it Harmony’s deepest mine. It has a life-of-mine of five years. Ore mined is treated at the Kusasalethu plant.

Brief History: Harmony acquired the Elandsrand and Deelkraal mines from the then AngloGold Limited in 2001. Shaft sinking of twin vertical shafts at Elandsrand had begun in January 1975 and was completed in December 1978, with first gold produced in 1979. Elandsrand changed its name to Kusasalethu in February 2010. Kusasalethu means “our future” in Zulu.

Products: Gold.

Geology/Mineralisation: Kusasalethu is situated in the West Wits basin and mines the Ventersdorp Contact Reef (VCR) as its main orebody.

The VCR facies model at Kusasalethu is based on the Paleotopographic or slope and terrace model. One structural and eight sedimentological facie types have been recognised at Kusasalethu. Four of the facies are thick, high-grade, geologically distinct reef terraces separated from one another by thin low-grade slope reef. The sand-filled channel is a thick low-grade facies. The Sandy Terrace complex is found on the same elevation as Terrace complex, but is a pebbly quartzite with no grade. The Mondeor conglomerates have been identified subcropping against the VCR in stopes in certain areas and have been delineated as a separate facies in these areas.

The Elsburgs conglomerates, found on the western side of Kusasalethu, form the footwall to the VCR and are part of the Turffontein Supergroup. It is a predominantly polymictic matrix supported conglomerate.

The VCR is overlain by the Ventersdorp lava belonging to the Ventersdorp Supergroup.

Geological discontinuities observed at Kusasalethu include faults, dykes and sills. Sills may occur in the footwall in areas adjacent to certain dykes. Flat bedding plane faulting also occurs and results in reef duplication, elimination and brecciation. Faults and dykes are classified according to their relative geologic ages – pre-VCR, Ventersdorp, Platberg, Bushveld and Pilanesberg structures.

Reserves: Total mineral reserves as at June 30, 2017, were estimated at 4.9-million tonnes grading 6.85 g/t gold.

Resources: Total mineral resources as at June 30, 2017, were estimated at 25.1-million tonnes grading 9.13 g/t gold.

Mining Method: Kusasalethu employs the sequential-grid method of mining, which is an upside-down Christmas tree configuration. This method is used to direct seismic stresses away from current working areas into virgin rock areas.

Major Infrastructure and Equipment: Ore mined is transported by rail bound equipment to the shaft’s main orepass system where it gravity feeds to 115 level. Ore is then hoisted through the subvertical shaft to above 73 level, where it is transferred by conveyor belt to 73 level and gravity feeds to 77 level from where it is hoisted to surface through the rock and ventilation shaft. Owing to the depth of mining, major engineering infrastructure is complex. Infrastructure includes refrigeration and cooling installations on surface and underground.

Ore mined is processed on site at the Kusasalethu gold plant. Gold is extracted using milling, cyanide leaching, carbon-in-pulp concentration and electrowinning to absorb the carbon to produce doré. No smelting is done on site.

Prospects: Kusasalethu is expected to remain profitable, focusing on higher-grade areas and benefiting from maintenance and engineering improvements conducted in the 2017 financial year.

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