The Highveld Coalfield is located in southeastern Mpumalanga Province, immediately south of the Witbank Coalfield. The width of the coalfield is some 95km, stretching from Nigel and Greylingstad in the west to Davel in the east, and is about 90km long, from just north of Kriel to beyond Standerton in the south and covers an area of approximately 7,000km2. After the Witbank Coalfield, the Highveld Coalfield is the next largest producing coalfield, on a tonnage basis, in South Africa.

The coalfield is host to up to five coal Seams contained within the middle Ecca Group sediments of the Karoo Supergroup, approximately 280 million years in age. And is characterized by the fact that in the northern regions, almost all the coal Seams, attain mineable thicknesses with economic potential. At Zibulo Colliery only Seam 2 and Seam 4 are mined. First seam 2 is mined, seam 4 which is easier and shallower will be mined at a later point in time.

The depth to the coal Seams increases in a southerly direction, it can be mined by opencast in the Kriel (northern) district, while it occurs at a depth of around 200m in the Standerton (southern) district. The coal Seams are generally flat-lying to gently undulating with a slight regional dip to the south.

Zibulo Colliery is sited within the Witbank Coalfields, which are usually comprised of five seams numbered. The colliery extracts No. 2 seam. The disturbed and relatively shallow coal seam is mined using the bord and pillar method due to the low capital investment and operating costs required, together with its level of selectivity and safety.

Coal is hauled by means of both battery haulers (BHs) and shuttle cars (SCs) at Zibulo Colliery’s underground operation. The background of the coal hauling equipment at the eight sections of the mine.

A total of 21 new coal haulers were ninitially purchased; 9 SCs and 12BHs. The SCs were employed in sections 1, 2, and 3. Sections 4, 5, 6, and 7 were using BHs. During this start-up phase, three redundant BHs were purchased from Goedehoop colliery, an Anglo American Thermal Coal underground operation.

Coal mined at the Zibulo Underground Colliery is transported directly to the plant by means of an interconnecting conveyor system, Zibulo Opencast coal is road hauled .

Coal from Zibulo Colliery is processed at the Phola processing plant – an Anglo American Inyosi Coal/ BHP Billiton joint venture operation. Zibulo Colliery is connected to the Phola Processing Plant by means of the long, undulating and curved overland conveyor which transports 1 650 tons/hour of ROM coal.

The Phola coal washing plant (beneficiation plant) conveyor system consists of 21 conveyors of which the longest are about 2 km long. The complexity of the system is due to the joint venture between BHP Biliton and Anglo American Inyosi Coal. The conveyor system feeds coal from both mine sites to the Phola coal washing plant.

The coal washing plant separates the coal into two products, i.e. coal for Eskom consumption and coal for export. From the product stockpiles coal is loaded into unit trains consisting of 100 wagons via 8 000 ton silos and load-out stations. The conveyor system can also bypass the product stockpiles and deliver the coal directly to the load-out silos for export use for both companies. The silos are 70 metres high for both Eskom and export purposes.