Highveld coalfield hosts up to five coal seams in the middle Ecca Group sediments of the Karoo Supergroup. The stratigraphic sequence in the mine area includes five coal seams that can be correlated with seams found in the Witbank coalfield, named from the base upwards as seam 1 (S1), seam 2 (S2), seam 3 (S3), seam 4 (S4) and S5. Seam splitting is common feature in the area. This is fundamentally attributed to the proximity to the Smithfield Ridge and thus the provenance of detrital material. S2 may be split into seam 2 upper (S2U) and seam 2 lower (S2L) while S4 is split into three subseams, seam 4 lower (S4L), seam 4 upper (S4U) and S4A. Furthermore, S4A may be split into S4A1 and S4A2. S5 is generally split into the S5 and seam 5 lower (S5L).

The thickest and most ubiquitous being the S2, S4 and S5 seams. S1 is restricted to palaeo-lows while S3 only occurs on the western side of the complex. The principal economic seams currently exploited are S2L and S4L, with the remaining seams being either too thin, laterally discontinuous, poor quality or impractical/uneconomical to mine.

FZO complex is characterised by two adjoining palaeo-valleys, one in FZON and the other in FZOS. The valley in FZON has higher-quality coal while FZOS is characterised by lower-quality coal. The different coal qualities are indicative of different depositional environments and thus the different geological domains. Remnants of the Smithfield Ridge exist in the north-western ........

The Forzando complex covers 13 233ha and comprises two underground operations, namely Forzando North and Forzando South with Forzando North placed under care and maintenance in March 2020. Forzando South is characterised by mechanised bord-and-pillar mining using a suite of continuous mining equipment. The operation is currently exploiting the S4L with four continuous mining sections, and is supported by a fleet of primary and secondary mining equipment. Forzando North also used mechanised bord-and-pillar mining using a suite of continuous mining equipment to exploit primarily the S4L although S2L was also previously exploited.

RoM from Forzando South is conveyed by surface to the beneficiation plant at Forzando North supporting the export market.

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