Khwezela North is located in the Witbank Coalf ield where f I've coal seams are present. These consists of, from bottom, the No 1 Seam, sequentially to the No 5 Seam at the top and all contribute to the resource and reserve base. At Navigation pit, all seams, with the exception of the No 3 Seam, to a greater or lesser extent, have previously been mined underground, with the select portion of the No 2 Seam mined most extensively. The No 4, 2 and 1 Seams currently contribute to the colliery’s export product.

Washouts have been intersected in the north where the coal seams have been eroded by palaeo-rivers, with the resultant channels filled with clastic sediments. The edges of the washouts are irregular due to differential compaction. Northeast – southwest trending floor rolls are also encountered.

Both the No 1 and the No 2 Seam occur, separated by the No 1 Seam parting (P1). The floor to the No 1 Seam consists of a thin carbonaceous shale band, which conformably overlies a reworked tillite of the Dwyka Formation. The No 1 Seam is present over the majority of the Navigation area and has been previously mined via underground workings (bord and pillar). It averages 1.27 m thick but reaches a maximum thickness of 2.63 m.

The P1 is variable in thickness, ranging from zero to 4.20 m with an average thickness of 1.74 m.

The No 2 Seam is present across the entire Navigation area; the select portion of the seam ( the Number 2 Seam Select, S2 ........

The Navigation pit is an opencast operation with a pre-strip operation allocated to a truck and shovel fleet. The overall stripping ratio is low compared to other similar opencast operations. The main operational risks are the potential spontaneous combustion in the old workings and local subsidence effects.

The primary mining equipment includes a dragline, hydraulic shovels, haul trucks, overburden drills and a coaling drill and is supported by the necessary ancillary equipment.

The mine design is planned to maximise the use of the dragline excavating the interburden material between the No 2 and No 4 Seams. The remaining material above the No 4 Seam and the No 5 Seam, which is a combination of soft and hard overburden, is excavated with a truck-shovel fleet. This process material allocation allows the pre-strip and No 5 Seam to be in advance of the dragline operation whilst allowing the maximum use of the dragline, which is the most cost-effective method of interburden removal. The large degree of underground workings dictates that buffer blasting is required; the dragline is the most effective for this.

The material excavated by the truck-shovel in advance of the dragline is then trucked around the pit and placed on the spoils or on the available spoil dump areas at the beginning of the pit. The access to the coal and for the dragline relocation will be through highwall ramps to the No 4 Seam elevation and by a lowwall ramp to access the No ........

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