Surface material at Mafube consists of weathering products of the sandstones, siltstones and mudstones of the Vryheid Formation. The top layer consists of reddish-brown sandy soil, with clayey sandy subsoil below.

Weathering is deepest in the south and west, and shallowest in the north and east, following the general trend of the topographic surface. The average depth is 9.9 m, reaching a maximum of 23.28 m.

The Mafube area is underlain by a sequence of sedimentary rocks of the Dwyka Group and the Vryheid Formation of the Ecca Group (Karoo Supergroup), which rest unconformably on an uneven floor composed of older gabbro and granodiorite (associated with the Bushveld Igneous Complex) as well as felsite of the Transvaal Supergroup.

The generally flat-lying Vryheid Formation consists of sandstone, siltstone, shale and coal seams. Strata at Mafube are typical of the Witbank Coalfield, with four of the five coal seams being present. Underlying the coal sequence of the Vryheid Formation are glacial deposits of the Dwyka Group, which accumulated on the erosional pre-Karoo basement surface.

The palaeotopography of the pre-Karoo basement largely controlled the deposition of the lower coal seams and partings.

The glacial deposits of the Dwyka Group vary within the project area and consist of fine-grained varved siltstone and shale to very coarse, matrix supported tillites. Clasts within the tillite are typically felsite from the Rooiberg Group, or sandstone and quartzite of the Wilge River Formation of the Waterberg Group.

Within the Ecca Group, the Vryheid Formation comprises zones of alternating conglomerates, sandstone and mudstones within which the coal seams are located. At Mafube, the stratigraphy of the Vryheid Formation may be divided into two main sequences: a basal No 2 Seam Sequence, overlain by the No 4 Seam Sequence.

Four of the five major Witbank Coalfield seams exist within the Mafube Nooitgedacht area. These are (from bottom to top), the No 1 Seam, No 2 Seam, No 3 Seam and the No 4 Seam. The No 4 Seam is confined to the deeper parts (northwest) of the mining area.

The No 4 Seam averages 4.68 m thick. It is confined to the extreme northwest of the Mafube area due to erosion and generally consists of several plies of differing coal quality.

The No 3 Seam is thin and of no current economic significance (average thickness of 0.2 m).

The No 2 Lower Seam (S2L) is the main economic seam with an average thickness of 4.23 m. The quality is variable due to interbedded bright and dull coal plies with some shale and carbonaceous shale, mudstone and occasional sandstone bands. An upper sub-seam, designated No 2 Upper Seam (S2U), is sometimes present. The S2U and S2L are separated by a thin but distinctive parting (designated Number 2 Seam Parting (P2) with an average thickness of 0.41 m). The S2U is fairly thin (averaging 0.77 m in thickness) and consists of poorer quality coal and is therefore not economic.

The No 1 Seam (S1) is thin (average thickness of 1.38 m) and continuous throughout the Mafube area. It lies approximately 0.5 m below the S2L. Two minor seam splits of the No 1 Seam (designated S1L and S1LL) occasionally occur. They are, however, of no economic significance.

The extraction of coal at Mafube is based on opencast mining methods currently focused in the Nooitgedacht area. The LoM plan is based on the extraction of coal from six opencast areas namely:
• Pit MGA;
• Pit MGB;
• Pit MGC;
• Pit MGD;
• Pit MGE; and
• Pit MGF.

Mining operations are based on a combination of contractor and owner-operated mining. Mining contractors were appointed to remove topsoil at an average thickness of 0.8 m and to remove the weathered burden material (softs) at a width greater than the strip width. This prevents the flow of soft over the hard overburden highwall and allows sufficient room for pre-split drilling activities. The presplit holes are drilled to the floor of the coal seam and production drilling to the roof of the coal seam directly below the hard waste burden. Pre-split drilling activities are designed to drill through the hard waste burden to the floor of the coal seam directly beneath. Once the presplit drilling and blasting is completed (conducted before burden drilling and cast blasting to avoid damage to the highwall of the pit), production drilling activities commence. Burden drilling and cast blasting is to the roof of the coal.

Blasted burden waste material is dozed down to a predefined level above the relevant coal seam. This level was pre-determined by a combination of burden thickness and coal seam thickness as contained within the “Dozer percentage” curve in the mine scheduling model. The remaining hard waste burden is removed by owner truck and shovel fleets to expose the coal seams. In areas where the parting thickness between the No 2 Lower Seam and the No 1 Seam exceeds 0.3 m, the parting is removed selectively by mine-owned excavators and haul trucks to expose and mine the No 1 Seam as a subsequent task. Where the parting thickness is less than 0.3 m, the No 2 Lower Seam, the parting and the No 1 Seam are removed as a single mining horizon.

Based on site-specific information, additional geotechnical parameters considered in the mine design and production schedule included:
• The design of the weathered material (topsoil and softs) benches was based on a width greater than the strip width to prevent the movement of weathered material over the highwall back into the pit;
• The maximum softs thickness, included in the blasting bench, was limited to 5 m and all excess material was scheduled for removal by truck and shovel operations;
• The softs bench was designed at a batter angle of 45° towards the lowwall side;
• Pre-split drilling and blasting activities were allowed for on all competent waste material before cast blasting activities commence;
• Pit wall berms of 10 m were allowed for between the softs and overburden hards benches; and
• Pit wall berms of 10 m were left between the overburden hards and coal benches.

The equipment used as the basis for the LoM exploitation strategy for each of the mining horizons can be summarised as:
• No 4 Seam, No 2 Lower Seam and No 1 Seam coal in the pit is exposed mainly by a Hitachi EX3600 coal excavator and Komatsu 730E coal haul trucks;
• Topsoil and softs are removed by a mining contractor fleet;
• Hard overburden and interburden are removed by a combination of dozing by a fleet of Cat D11 dozers and waste hauling through a fleet of Hitachi EX3600 waste shovels and Komatsu 730E waste haul trucks; and
• A fleet of Sandvik DR461i overburden drills are used for pre-split drilling with a fleet of Sandvik SK45S burden drills utilised for the infill burden drilling.

Two of the six LOM pits are currently being mined and the No 2 and No 1 Seam are being extracted.

- subscription is required.

The RoM tip was relocated to the new area and is linked to the CHPP by a 7 km overland conveyor belt. The CHPP is linked to the Rail Load-out Terminal (RLT) by a 14 km overland conveyor.

The plant is operated by the Company on behalf of the JV.

The washplant is a single module, treating coarse and small coal, plus and minus 8 mm, in separate dense medium cyclones (DMC). The discard from these two circuits is combined and fed to a high gravity dense medium cyclone circuit. The plant produces two types of coal: an export product (AAC) and a middling product (PRE). The middling coal was originally delivered to Arnot Power Station, but that contract has been discontinued. Both types of coal are stockpiled at the CHPP and delivered batchwise by a 14 km overland conveyor belt to the RLT.

The plant uses filter presses to process the ultrafine coal (nominally minus 150 microns). If possible, the filter product is sold, but this depends on the market. The ultra ........