The Bushveld layered sequence around Modikwa strikes north-northwest to south-southeast and dips to the south-west at 10º to 12º, with local variations in the dip resulting in gradients of nearly 20º. There are several instances where some gentle “rolling” of the reef horizons have been recorded, and normally steeper dips are noted nearer the outcrop (as opposed to at depth).

The outcrop positions of the Merensky Reef and the UG2 Reef normally occur within the areas of low relief, and much of the outcrop is masked by extensive development of black turf as well as, in places, transported sediments. On the farms Maandagshoek 254 KT, Onverwacht 292 KT and Winterveld 293 KT; however, the UG2 Reef (and occasionally the Merensky Reef) outcrops in a series of elongated hills. Although frequently covered with scree material, much of this outcrop has been marked by a series of trenches and pits, many of which date from early pioneer prospecting.

Both the UG2 and Merensky reefs are present at Modikwa. The UG2 Reef occurs as a chromitite layer with an average thickness of approximately 60 centimetres. Three leader chromitites occur above the main seam. Gentle undulations of the UG2 Reef with amplitudes of less than 2 metres are developed across the mine area. Potholes are randomly distributed within the North shaft area but are less abundant in the South shaft area. The Onverwacht Hill area in the southern portion of the mine is characterised by the presence of several large ultramafic pegmatoid intrusions that disrupt, and locally replace, the UG2 Reef.

Mining consists of mechanised development and conventional stoping. The UG2 is accessed via two primary declines from the surface, and South 2 shaft.

To maintain the current production profile and ramp-up production, Modikwa Mine initiated the North shaft and South 2 shaft projects:
• North shaft project – level 9 decline equipping was completed and commissioned. Level 9 strike development has started. The decline to level 10 is scheduled to commence in the first quarter of F2022;

• South 2 shaft system produced an average of 51 258 tonnes per month in F2021. The project is on track and the opening of more working areas in the system achieved an average of 57 795 tonnes per month in 2H F2021. The mine is ramping up production.

Run-of-mine tonnage is processed at the Modikwa concentrator and the PGE-rich concentrate is transported to Anglo Platinum’s Polokwane smelter and refining facilities.

Commissioning of the Chrome Recovery Plant (CRP) is underway as planned.

PROCESSING PLANT
Froth flotation is the primary mineral processing separation step employed in the beneficiation of PGM ore bodies. Anglo Platinum operates a significant portion of the total installed flotation capacity in the PGM industry, which is installed at 20 operating plants across the Bushveld.

Anglo Platinum has 20 operating concentrators sited around the Eastern, Northern and Western limbs of the Bushveld complex. The concentrators treat mainly Merensky and UG-2 ores, with Potgietersrust (PPL, Sandsloot) and PPRust North being the only two plants designed to treat the Platreef ore.

For typical UG2 ores, for example, the finer natural PGM grain size in the in situ ore and the relative perfo ........