Greenside colliery 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, with inter-seam partings consisting of mainly shale or siltstone and sandstone, with thicknesses ranging between 1.5 m and 23 m. The No 4 Seam is currently the only contributor to the colliery’s export product.

The colliery is sub-divided into two distinct domains, by a major northwest, southeast trending normal fault system with a measured maximum throw of 30 m in the southeast. The throw gradually
decreases to a ~1 m throw towards the northeast. Mining has been constrained by the fault system, with development from the east and west, stopping on approaching the fault zone. Several dolerite dykes have been identif ied by drilling and mining, but the impact on mining is limited to occasional cases of poor ground conditions experienced during mining.

Surface material at Greenside consists of weathering products of the sandstones, siltstones and mudstones of the Vryheid Formation, with isolated patches of dolerite in the southwestern part of the GAR. The top layer consists of reddish-brown sandy soil, with clayey-sandy subsoil below.

Weathering generally does not extend deeper than approximately 12 m at Greenside, except where adjacent to dolerite dykes and close to surface water bodies. In these instances, weathering may reach up to 17 m below the surface. Weat ........

Greenside is an underground colliery using mechanised bord and pillar mining to exploit the coal within the GAR. There are five CM sections, all currently in the northwestern part of the mine. The three coal preparation plants produce an export-grade product that is sold through the RBCT. A domestic product is derived from recovering MRD material and blending it with some of the primary product discard material; this is sold into the domestic market via third parties.

The main target seam is the No 4 Seam as the No 5, No 2 and No 1 Seams were mined previously. Pillar coal remains and may be considered a resource in the future, provided suitable studies are conducted to demonstrate viability. Future mining will move to the southeast into East Block, where the coal is of somewhat lower quality and reduced thickness.

The first cut-off parameter used is a minimum mining height of 2.5 m, governed by the restriction on the mining equipment (CMs). The minimum roof depth cut off is set at 20 m to surface to avoid potential weathering of the coal seam.

The following general criteria were used to design the layouts:
• Primary developments: 9 - 10 roads per panel;
• Secondary developments: 9 - 10 roads per panel;
• 15 to 16 m centres for square bord and pillar sections– depending on safety factors and width-to height ratios, a minimum 16 m centre is used. This suits the advance of the CM in terms of cutting depth without support and minimi ........

The mine currently has three plants, one to wash raw, primary mined coal known as the ”4 Seam plant”, one to primarily wash discard material from the very large mineral residue deposits, known as the “5 Seam plant” and a later plant which only treats the ultrafine material from the No 4 Seam plant.

No 4 Seam Plant
Underground operations run from Monday morning 6 am to Saturday morning 6 am, so the stockpiles need to be reasonably full to ensure that the plant can operate as planned over the entire weekend. The No 4 Seam plant consists of three modules, with Modules 1 and 2 being identical and joined by a common fines (spirals) plant. Module 3 is separate and has its own fines (spirals) plant. Ultrafine coal, nominally minus 150 microns, from the three modules is sent to a flotation plant for recovery of coal, which is dewatered using filter presses. Presently, the No 4 Seam plant produces a primary product of 5 800 kcal/kg Net As Received Calorific Value and a middlings ........