The Bushveld stratigraphic sequence at Zondereinde is typical of the northern portion of the western limb. The Critical Zone stratigraphy is compressed and dominated by mafic lithologies, with the vertical separation between the Merensky and UG2 Reefs ranging between 20 m and 40 m. Both reefs dip at 20° towards the south-east and extend from a depth of 1 100 m to 3 000 m below surface.

While there is lateral continuity of both reefs across the mine property, the Merensky Reef displays a variety of reef sub-types. The distribution of these is determined from a combination of surface exploration boreholes, ongoing prospect drilling from underground development and on-reef mapping in mine excavations.

Merensky Reef
The Merensky Reef is a zone of mineralisation that straddles the base of the Merensky cyclic unit. In the area of Zondereinde mine, the Merensky Reef consists of two sub-facies of the Zwartklip facies, namely the Normal and Regional Pothole sub-facies. The latter may be further subdivided into three sub-types, each of which occurs at a specific stratigraphic level below that of the Normal sub-facies. Sub-types include NP2 and P2, which constitute the main sources of ore, and FWP2 which, whilst not historically considered a primary mining target due to its undulating morphology in the central portions of the mine, is now successfully exploited in the western portion of the current mining area where it displays lesser disruption. This trend is ........

Mining of the narrow tabular orebodies in the intermediate to deep level mining environment is successfully conducted using a conventional mining method. The mining layout is a breast configuration on both the Merensky and UG2 Reefs. The Merensky Reef excavation is backfilled, which has, historically, then been followed by the extraction of UG2 Reef in a destressed mining zone. UG2 operations are migrating to areas where there has been no previous Merensky mining. In these areas, support regimes and layouts similar to those employed on the Merensky Reef are adopted.

The underground workings are accessed from a twin vertical shaft system. The Number 1 Shaft extends below 13 level (2 102 m below surface) and Number 2 Shaft serves workings down to 8 level (1 724 m below surface). The shafts have a lateral separation of 90 m and are interconnected at an intermediate pump chamber (IPC) at 1 019 m below surface, as well as on mining levels 2, 4, 6, 7, 8 and 9. Workings below 13 Level are serviced by decline access ways, designed to accommodate both people and materials, and equipped with a conveyor belt system that transports the ore and waste rock. The relatively narrow vertical separation between the two reef horizons allows for both of these to be accessed via the same primary tunnel development.

The vertical interval between levels is 63 m. With the ore body dipping at 20°, this provides a raise back length of 180 m and allows for six stoping panels of 30 ........

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