Khwezela Operation (Landau and Kleinkopje Collieries) consists of two sections, namely the Kromdraai Section and the Navigation Section (Navigation West extention).

Surface material at Khwezela (Figure 4-4) consists of weathering products of the sandstones, siltstones and mudstones of the Vryheid Formation, with a small area of weathered doleritic material found in the southern-most corner of Khwezela North. The top layer consists of reddish-brown sandy soil, with clayey-sandy subsoil below.

The depth of weathering across Navigation and Bokgoni varies between five and twelve metres; the overburden material is therefore likely to be relatively competent. However, deep weathering may be encountered below the wetlands in the SACE Lifex areas.

Navigation
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 reac ........

The Bokgoni Pit was placed on care and maintenance in December 2020 due to the prevailing economic conditions; as such, no Coal Reserves have been declared as a new mine plan would need to be developed by the Company in order to extract any future coal, should economic conditions improve sufficiently. Additionally, select mining equipment has been reallocated to other sections, including the Navigation Opencast Section.

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 2 and No 1 Seams. Pit access will be not be optimal due to the small s ........

Navigation CHPP
The Navigation Tip consists of a 1200x1200 mm static grizzly above a primary bin. The -1200 mm material is extracted via an apron feeder and fed onto a vibrating grizzly with an aperture size of between 80-100 mm. The grizzly oversize is fed into a jaw crusher and crushed to -350 mm. The material is then fed into a single rotary breaker for reduction to between 80-100 mm. The crushed material from the rotary breaker joins the vibrating grizzly undersize material and conveyed to the RoM bunkers which were previously used to receive railed and trucked RoM coal. Rotary breaker waste is fed to a 300 t rock bin for disposal back to the pit.

Bokgoni CHPP
Each tip has grizzlies with 750 mm x750 mm apertures onto which coal is tipped by trucks. The coal passes through the grizzlies into the RoM bins, each of which has a 1 200 t capacity. Below each of the RoM bins are feeders which feed raw coal into their respective rotary breakers. The rotary breaker picks the coal up four to five times, the coal preferentially breaks and falls through 150 mm diameter holes. Numerous magnets are positioned to attempt to remove some of the extraneous metal in the feed. Some material will not break, passes through the breaker and is rejected.

From Tip B (and previously Tip A), the reject from the rotary breakers passes to the W1 Conveyor and into a stone bin. This waste is taken back to the mine by trucks loaded from the stone bin. The coal from the Tip C bin is also fed onto a vibrating grizzly cutting at 150 mm, with the +150 mm material being fed into the rotary breaker.

In the past, the rotary breaker reject was fed into a jaw breaker to reduce all the material to -150 mm as the roof coal and the discard material is considerably harder and potentially contains more of the lower grade product coal for which it will be washed. The crushed oversize material is then combined with the rotary breaker underflow. However, this has now been changed and the jaw crusher has been taken out of circuit. The circuit is now essentially the same as Tip B, with the waste rejected from the rotary breaker joining the waste from Tip B.

Kleinkopje and Landau were two of the original plants in the original submission to the Japanese steel mills to produce low ash coal.

Navigation CHPP
The Navigation CHPP replaced the Landau CHPP in 1992, processing coal from the Kromdraai Pit. The same infrastructure is now used to process the RoM from the Navigation Pit instead. The plant consists of two identical modules, A and B. The wash plant has had modifications, which will be described, but the major change has been the change in feed coal from the now-depleted Kromdraai Pit to the Navigation Pit. This is planned to extend the life of the reserves by eight years.

The Coal Handling Preparation Plant (CHPP) has a nameplate throughput capability of 6.0 Mtpa (nominal), but this has never been achieved due to a lack of RoM. The best feed-to-plant (FTP) achieved was 5.64 Mt in 2012. The plant was originally conceived as a two product plant, with two stages. The second stage cyclone plants were replaced by u ........