Name: Modikwa mine.

Location: Modikwa is situated about 15 km north of Burgersfort and 15 km north-west of Steelpoort, along the border between South Africa’s Mpumalanga and Limpopo provinces.

Mine Owner/s: African Rainbow Minerals (ARM) has an attributable beneficial interest of 41.5%, through its 83% ownership of the ARM Mining Consortium; 8.5% is held by the Mampudima and Matimatjatji community companies through their 17% shareholding in the ARM Mining Consortium; and 50% is held by Rustenburg Platinum Mines.

Brief Description: Modikwa is an underground platinum group metals mine.

Brief History: Exploration in the area started in the mid-1920s, with the discovery of the Merensky reef. During the late 1980s, drilling was undertaken on the upper group two (UG2) and Merensky reefs. In the late 1990s, a feasibility study was completed for the exploitation of the UG2 reef. During 2001, a 50:50 joint venture agreement was signed between Rustenburg Platinum Mines and ARM Mining Consortium.

Primary Metals/Minerals: Platinum, palladium, rhodium and gold (4E).

Secondary Metals/Minerals: None stated.

Geology/Mineralisation: The Bushveld layered sequence around Modikwa strikes north-north-west to south-south-east 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 and the UG2 reefs usually appear within the areas of low relief, and much of the outcrop is concealed by extensive development of black turf, and, in places, transported sediments.

Both the UG2 and Merensky reefs are present at Modikwa. The UG2 occurs as a chromitite layer with an average thickness of 60 cm. Three leader chromitites occur above the main seam. Gentle undulations of the UG2, with amplitudes of less than 2 m 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.

Reserves: Total proven and probable reserves as at June 30, 2020, were estimated at 45.73-million tonnes grading 4.22 g/t 4E.

Resources: Total measured and indicated resources as at June 30, 2020, were estimated at 188-million tonnes grading 5.92 g/t 4E. Inferred resources were estimated at 77.5-million tonnes grading 6.22 g/t 4E.

Mining Method: Underground – mining comprises mechanised development and conventional stoping.

Flowsheet: The UG2 is accessed through two primary declines from the surface, and South 2 shaft. Run-of-mine tonnage is processed at the Modikwa concentrator. Thereafter, the platinum group elements-rich concentrate is transported to Anglo Platinum’s Polokwane smelter and refining facilities.

Prospects: ARM aims to complete and commission the construction of the chrome plant in the fourth quarter of 2021.

Contact Details:
ARM
Tel +27 11 779 1300
Email ir.admin@arm.co.za
Website: www.arm.co.za