The iMpunzi Complex falls within the southern margin of the central portion of the Witbank-Springs Coalfield. The coalfield is underlain by pre-Karoo formations, mainly Bushveld felsite. Historic glaciation events resulted in the deposition of tillite (Dwyka Formation) over most of the area. Within the Karoo Sedimentary Sequence the Ecca Group rests on top of the Dwyka Formation. In the Witbank-Springs Coalfields the coal bearing Vryheid Formation occur at the bottom of the Ecca Group conformably to the underlying Dwyka Formation.

The Dwyka Formation consists of tillite, siltstone and sometimes a thin shale development. The Ecca Group consists predominantly of sandstone, siltstone, shale and coal. The Vryheid Formation in the Ecca Group contains five bituminous coal seams, numbered as No. 1 to No. 5 from bottom to top. The No. 2, No. 4 and No. 5 seams are the most economical coal seams to mine in the Witbank-Springs Coalfield.

The Tweefontein North development includes all five seams present in the Vryheid Formation. The 1, 2, 4 and 5 seams form part of the mineable and economic Coal Resources. The resources have the potential to be extracted via both opencast truck and shovel or dragline, and underground bord and pillar mining methods.

Tweefontein South Complex is contained in the Tavistock and Klippoortje old order mining authorisations, situated within the Witbank Coalfield. The complex development includes all five seams, however, only the 1, 2, 4 and 5 seams form part of the potentially mineable and economic Coal Resources.

The iMpunzi Complex consists of four (4) sections, namely: Arthur Taylor Colliery (ATC), Phoenix (decommissioned), Arthur Taylor Colliery Opencast Mine (ATCOM), and ATCOM East.

Currently all major opencast mining is undertaken using the strip mining method with draglines. All hard overburden (shale/sandstone) and coal is blasted using bulk explosives (heavy ANFO emulsion). The coal is transported by truck to the Crushing and Pillar Screening Plant. Smaller opencast areas are mined by truck-and-shovel techniquesto the Crushing and Pillar Screening Plant.

ATCOM

This opencast mine has 2 areas in which mining is being done – ATCOM North and the South Pit triangle (Plan 9e).

The North area has virgin No. 4 seam and No. 2 seam pillars which are mined by Dragline and truck and shovel operations. The overburden is removed down to the No. 4 coal seam which is then removed by a Company owned fleet. The interburden between the No. 4 and 2 seams is removed by Draglines. Coaling is again done by the company owned fleet.

The South Pit triangle contains all virgin coal on the No. 5, 4 and 2 seams. This area of operations will be done entirely by T&S fleets. The over and interburdens will be removed with the coaling undertaken by the company owned fleet. The rollover method will be done ensuring earlier and continuous rehabilitation. Currently a large area of the South Pit has been mined and a section has been rehabilitated. The remainder of the area forms part of the South Pit dump project and will therefore not be rehabilitated at this stage. The smaller triangle section will be mined once sufficient dewatering has been completed (2013) as per the license conditions.

ATC

The opencast area, the Butterfly, is being mined by contractors utilizing the truck and shovel – Rollover method. This operation should last until early 2013 and will then move to the Office Pit area utilizing the same method and will continue until 2018
(see Plan 9c).

The mining operations at ATCOM East consist of opencast mining, both dragline and truck and shovel. Using T&S the topsoil and overburden is removed down to the No. 4 seam coal which is then removed by a Company owned T&S fleet. The interburden between the No. 4 and 2 seams is removed by draglines. The No 2 seam coaling is again done by the company owned truck and shovel fleet.

The mining area has been divided into 5 separate areas – Steenkoolspruit, Vandyksdrif South, Vandyksdrif West, River Shaft South and River Shaft West. River Shaft West may be extended within the LOM of ATCOM East towards the north east towards Steenkoolspruit. The Dragline, supported by the T&S operations will be utilized at the Steenkoolspruit and Vandyksdrift South areas while the other 3 areas will be done by Truck and Shovel only. See Plan 10a and Plan 10b.

Tweefontein Complex.
Underground mining is conducted using conventional drill and blast methods (including total extraction mining, i.e. stooping), as well as fully mechanised, continuous miner equipment on a bord and pillar system.

Opencast mining is undertaken using the strip mining method with dragline. All hard overburden (shale/sandstone) and coal is blasted using bulk explosives (heavy anfo emulsion). The coal is transported by truck to the Crushing and Pillar Screening Plant. Smaller opencast areas are mined by truck and shovel techniques.

iMpunzi consists of an opencast mining complex, a coal handling and preparation plant, and the iMpunzi dump reclamation operations feeding to the ATC coal handling and preparation plant, which produce a combined 7 million tonnes per annum, of which approximately 55 per cent. is exported.

The coal is transported by a fleet of trucks to the crushing and pillar screening plant (Golder, 2016b).

Arthur Taylor Colliery (ATC)
The operation has its own coal processing plant and has rail load-out facilities for coal transportation, via the adjacent Transnet railway.

Arthur Taylor Colliery Opencast Mine (ATCOM)
The coal mined at ATCOM is transported to the ATCOM Central Plant where it is washed and conveyed to the linear stockpile at ATC. From there, it is conveyed to a rapid load-out silo situated at ATC, from where it is transported via rail to Richards Bay for export (Jones & Wagener, 2014).

Subsequent to the completion of the Tweefont ........