Kloof is located along the West Wits Line that forms part of the Far West Rand of the Witwatersrand Basin. The Witwatersrand Basin comprises a 6,000m vertical thickness of sedimentary rocks, extending laterally for some 350km northeast to southwest by some 120km northwest to southeast, generally dipping at shallow angles toward the centre of the Witwatersrand Basin. The Witwatersrand Basin outcrops at its northern extent near Johannesburg, but to the west, south and east it is overlaid by up to 4,000m of volcanic and sedimentary rocks.

Gold mineralisation occurs within laterally extensive quartz-pebble conglomerates called reefs, which are developed above unconformable surfaces. As a result of faulting and primary controls on mineralisation processes, the goldfields are not continuous and are characterised by the presence or dominance of different reef units. The reefs are generally less than two metres thick and are widely considered to represent laterally extensive braided fluvial deposits or unconfined flow deposits, which formed along the flanks of alluvial fan systems around the edge of an inland sea. Dykes and sills of dolerite composition are developed within the Witwatersrand Basin and are associated with several intrusive and extrusive events.

Gold generally occurs in native form, often associated with pyrite, carbon and uranium. Pyrite and gold within the reefs display a variety of forms, some obviously indicative of detrital transport within the depositional system and others suggesting crystallisation within the reef itself.

The Kloof ore bodies comprise four gold-bearing reefs, namely the Ventersdorp Contact Reef (VCR), the Middelvlei Reef (MVR), the Kloof Reef (KR), and the Libanon Reef (LR). The VCR, located at the top of the Central Rand Group, is the main exploited reef accounting for 68% of ore mining at Kloof, while the KR, MVR, and LR account for 21%, 9% and 2%, respectively.

Accordingly, both the Kloof and Libanon reefs subcrop below the VCR in the extreme north and south of the property. Approximate dip of all reefs is 25 to 35 degrees to the southeast and strike is approximately northeast southwest, however local variations in structure and the slope and terrace model can see these dips increase to 45 degrees.

Kloof Reef ("KR")
The KR zone is situated some 50m to 70m above the LR and it is exploited at Main Shaft, No. 3 Shaft, No. 7 Shaft and No. 8 Shaft. It comprises of a number of conglomerate bands and interbedded quartzites. The base of the zone is marked by a thin grit to small pebble conglomerate, called the Footwall Marker, overlain by coarse grained light green to grey quartzite.

The economic KR is known as the KRS1, and when payable it comprises robust large pebble conglomerates, generally oligomictic, but with polymictic upper bands common.

Above the reef, an argillaceous quartzite is present and varies from a few centimetres thick to less than 2m. This quartzite is often "blocky" due to the many bedding planes. An argillite marker or argillite parting can often be noted in this zone.

Above the argillite marker is a conglomerate (or occasionally a pair of conglomerates) known as the KRS2. These are small to medium pebble conglomerates usually oligomictic with generally sub-angular small white and smoky quartz clasts. It is often well mineralised and carries gold. Faulting in stopes often exposes this band.

Eight facies types are recognised for the KR.

A recent change to the KR facies model was undertaken in 2021 due to an investigation of faulting within the KR expansion project. A northeast southwest trending 25m downthrow fault (the Split Fault) was also found to have approximately 200m left lateral shift. This unexpected shift meant that the expected payshoot that the expansion project was based on shifted 200m further south. Additional development will therefore be required to access this payshoot. This shift can also be observed in the facies plan below.

The impact has considerably affected the Kloof K8 Upper project and the timing for stoping and has decreased the grade in these areas from 14 level to 18 level.

As Kloof is a well-developed orebody that has been extensively mined, the choice of mining method is constrained by this historical mining. The orebody is narrow tabular in nature and is accessed through vertical shafts, with evenly spaced development in the footwall. On reef development is advanced on true dip, with conventional finger or wide raises and then stoped to either side in the direction of strike. All mining at Kloof is conventional in nature and is consistent with other similar orebodies.

Mining methods are based on a number of factors and are shaft, infrastructure and orebody specific. The mining methods employed at Kloof are subdivided as follows:
- The predominant mining layout at Kloof Upper is breast stoping with dip pillars, as well as scattered mining;
- Predominant mining layout at Kloof Lower is scattered mining, characterised by mostly up-dip mining;
- Breast stoping with dip pillars was selected for the below infrastructure project; and
- Mining spans and pillar width depend on the location, the reef being mined and the depth of working.

No backfill operations are conducted. No stripping is required as operations are accessed through underground development and surface sources are readily available.

All mining, specifically from white areas, undergoes a continual risk assessment process and those areas that currently pose a risk are excluded from the Mineral Reserves.

Mineral Reserves generation is done through the development of footwall drives (approximately 90m in the footwall) and crosscuts to reef. Crosscut spacing is based on a selective grid (100m to 180m apart), depending on evaluation, rock engineering principles and structure.

Finger-raise development with breast ledging is done on the secondary reefs and in selected areas on the VCR where the HW consists of Alberton lava. The majority of the VCR mining at all shafts makes use of wide raising, with the HW consisting of Westonaria Formation lava ("WAF"), to ensure the excavation is properly de-stressed during development.

Kloof incorporates the No. 1 Plant situated near Main Shaft and the No. 2 Plant situated at No. 7 Shaft. Toll treatment of surface material on the Kloof MR occurs at Cooke Ezulwini Plant.

Kloof No. 1 Plant
Kloof No. 1 Plant, which was commissioned in 1968 to treat underground ore and comprised three stage crushing and two stage milling utilising open circuit rod mills for primary milling and closed-circuit pebble mills for secondary milling. After milling the pulp is thickened and air-agitated in cyanide leaching tanks. In June 2001 redundant drum filtration was replaced by a more efficient AAC pumpcell Carbon in Pulp ("CIP") circuit. Smelting was also discontinued with loaded carbon being transported to No. 2 Plant for elution, thermal regeneration and smelting. In 2008, No. 1 Plant started treating Surface Rock Dumps ("SRD") material and in 2013 all crushing was stopped, the secondary crushing circuit bypassed and modifications made on the conveyor feed ore delivery system, with the addition of an overland conveyor to allow screened material from the SRD's to feed the mill silos directly.

The current operational capacity of Kloof No. 1 Plant is 165kt per month, and the LOM scheduling has been planned accordingly. The main feed for the plant will be low grade surface material. The LOM plan assumes a recovery of 82.9% for surface material only, which is in line with historical performance adjusted for projected head grades. The milling circuit infrastructure is showing signs of aging, and maintenance requirements can be expected to steadily increase if this plant is to operate for the remaining LOM.

Kloof No. 2 Plant
Kloof No. 2 Plant, which was commissioned in 1990, currently treats most of Kloof's underground ore. If excess underground material is produced, this material is treated at No. 1 Plant. Reef is trucked and conveyed to a central stacker pad which feeds two SAG mills equipped with variable speed ring motor drives. There is an option to deliver surface material to the stacker pad when underground stocks are unavailable to utilise plant capacity. The two SAG mills can be operated as fully autogenous units, or as currently being operated, as semi-autogenous units by adding steel grinding balls. Milled ore is thickened ahead of cyanide leaching in air-agitated tanks and adsorption onto activated carbon in a conventional CIP circuit. Loaded carbon is eluted in an AARL elution circuit, which was upgraded in June 2001 and further in October 2003, and now serves as the central elution facility for Kloof. The upgrade included the installation of Continuous Electro-winning Sludge Reactors which are working very efficiently. Cathode sludge is filtered and smelted to produce doré.

The current operational capacity of Kloof No. 2 Plant is 165kt per month. The underground feed sources are Main Shaft, No. 4 Shaft, No. 7 Shaft and No. 8 Shaft. The plant is considered to be both mechanically and structurally in good condition. Surface stockpile material has occasionally been treated at No. 2 Plant since 2018, but no surface material is planned in the LOM. The LOM plan assumes a plant recovery factor ("PRF") of 97.7% for underground material.

The underground tonnages sent to the mill include waste development tonnages which are hoisted and frammed separately at the shaft and then sent through to the mill. The inclusion of these development tonnages exceeds the current plant capacity. The waste development will therefore be stockpiled at the plant and used to supplement the underground feed as required. The waste development has been planned at 0.0 g/t but in reality, has been shown to contain approximately 0.5 g/t and compliments the MCF when milled due to the occurrence of uncalled footwall bands.

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