Mineral Resources and Mineral Reserves
Two Rivers

Two Rivers is located on the eastern limb of the Bushveld Complex, some 35km south-west of Burgersfort. The location is shown in the adjacent map.

During 2001, Assmang elected to dispose of its platinum interests at the Dwarsrivier Chrome Mine. Two Rivers, the incorporated joint venture between Avmin and Implats, secured the platinum rights in December of that year. Subsequent corporate activity involving Avmin, ARM and Harmony resulted in the transfer of Avmin’s share in Two Rivers to a new, empowered platinum entity, ARM Platinum, a division of ARM. The joint venture partners began development of the Two Rivers project in June 2005. The concentrator plant was commissioned early in 2007 and in 2008 the mine successfully made the transition from project to operation.

Two Rivers holds a contiguous old-order mining right over 2 140ha on a portion of the farm Dwarsrivier. The conversion to a new-order mining right was executed during 2013. The operation is managed by ARM and Implats has a 45% stake in the joint venture.

Shareholders should note that agreement has been reached to incorporate portions 4, 5 and 6 of the adjoining farm, Kalkfontein, as well as portions of the farm Tweefontein held by Impala, into the mining area. When this happens, Implats’ effective interest will increase to 49%. Agreement has also been reached to transfer the remaining Implats owned mineral rights on portions of the farms Kalkfontein and Buffelshoek to Two Rivers in exchange for a royalty payment. These transfers had not been effected as at 30 June 2014. Additional details can be found in the Tamboti section of this report.

Both the Merensky and UG2 Reefs are present but only the UG2 is currently exploited. The UG2 Reef outcrops in the Klein Dwarsrivier valley over a north-south strike of 7.5km and dips to the west at 7° to 10°. The vertical separation between the Merensky and UG2 Reefs is around 140m. Due to the extreme topography, the Merensky Reef outcrops further up the mountain slope.

The topography also means that the UG2 occurs at 935m below surface on the western boundary. The geological succession is broadly similar to other areas of the eastern limb of the Bushveld Complex. Three distinct reef types have been defined for the UG2 Reef, namely the “normal” reef with a thick main chromitite layer; a “split” reef characterised by an internal pyroxenite/norite lens within the main chromitite layer; and a “multiple split” reef with numerous pyroxenite/norite lenses occurring within the main chromitite layer. The multiple split reef predominates in the southern portion of the mining area.

The Merensky Reef is a pyroxenite layer with a chromitite stringer close to the hangingwall contact and also at the basal contact. Mineralisation is primarily associated with the upper and lower chromitite stringers. The grade profiles at Two Rivers are generally similar to that at the adjoining Tamboti Project. The graphical illustration of the profiles is shown in the Tamboti section.

The UG2 orebody is accessed via two decline shaft systems situated 3km apart, namely the Main Decline and the North Decline. Reef production is through a fully mechanised bord and pillar stoping method. A mining section consists of eight 12m bords, with pillar sizes increasing with depth below surface. In the shallow areas up to 100m below surface, the pillars are 6m x 6m in size. The rooms are mined mainly on strike.

A 3D geological model with layer grades and widths per stratigraphic unit is utilised. The mine scheduling of the two declines is done in Mine 2-4D^TM. The schedule is evaluated against the grade and thickness block model. The three distinct reef types impact significantly on the mine plan.

Dilution calculations are based on the specific reef type and pay limits are applied to the final mining cut. Hangingwall and footwall overbreak, percentage off-reef, ore remaining (mining losses), geological losses (potholes, faults, dykes and replacement pegmatoid) and a shaft call factor are applied to the planned areas to generate the tonnage and grade profiles.