Name: Mimosa mine.

Location: The mine is located in the Wedza subchamber of the Great Dyke. in Zimbabwe, about 32 km west of Zvishavane.

Mine Owner/s: Mimosa Mining Company, jointly owned by Impala Platinum and Sibanye-Stillwater on a 50:50 shareholding.

Brief History: Mining operations have been conducted in the Mimosa area since the 1920s.

Mimosa was acquired by Zimasco from Union Carbide in 1993. Zimasco piloted platinum mining in Zimbabwe by resuscitating the operation and steadily increasing production to the 1 000 t/d achieved in 1998.

Impala Platinum (Implats) acquired a 35% stake in Mimosa for a consideration of R246-million in July 2001. This stake was increased to 50%, with a further acquisition of 15% in August the following year. Aquarius Platinum acquired a 50% stake in Mimosa during the same year.

In 2016, Sibanye-Stillwater acquired all the shares that formerly belonged to Aquarius, making them Implats’ partner in this joint venture.

Brief Description: Mimosa is an ongoing shallow, mechanised platinum group metals and base metals mining operation on the South Hill ore deposit, comprising the Wedza and the Mtshingwe shafts. The Wedza shaft, on the northern part of South Hill, has been extensively mined, while Mtshingwe shaft is at development stage.

It is estimated that the current mineral reserves will sustain operations until 2032.

Primary Metals: Platinum, palladium, rhodium and gold (4E) platinum-group metals (PGMs); and platinum, palladium, rhodium iridium, ruthenium and gold (6E) PGMs.

Secondary Metals: Base metals.

Geology/Mineralisation: The Great Dyke is a layered complex similar to that of the Bushveld Complex, in South Africa. It extends 550 km and has a maximum width of 11 km.

Within the Great Dyke, four geological complexes are known to contain platinum group metals and base metals deposits. These are the Wedza complex, comprising Mimosa (Sibanye-Stillwater and Implats), the Selukwe complex, comprising Unki (Anglo Platinum), the Hartley geological complex, comprising the Hartley and Ngezi platinum mines (Zimplats) and the Musengezi complex.

The Hartley geological complex is the largest of the PGM-bearing

complexes, containing 80% of the known PGM resources in Zimbabwe. The stratigraphy is broadly divided between a lower ultramafic and an overlying mafic sequence.

The ultramafic sequence hosts the P1 pyroxenite, which in turn hosts the economic PGM-bearing main sulphide zone (MSZ), which is generally 2 m to 3 m thick. Optimal mineralisation varies and, in contrast to the Bushveld Complex, is often difficult to follow visually.

Mimosa has a well-defined grade profile where peak base metal and PGM values are offset vertically, with palladium dominant at the base, platinum in the centre and nickel towards the top.

Reserves: Total proven and probable reserves as at December 31, 2018, were estimated at 16.5-million tonnes grading 3.5 g/t 4E and 3.7 g/t 6E.

Resources: Total mineral resources as at December 31, 2018, were estimated at 57.2-million tonnes grading 3.6 g/t 4E and 3.8 g/t 6E.

Mining Method: Bord-and-pillar.

Major Infrastructure and Equipment: The mine features two adits – Blore and Wedza – for access to the mine and materials handling; a 21 km underground conveyor network with ore bunker; two 850 kW, four 280 kW, two

220 kW and one 900 kW main primary exhaust fans; ten raisebore ventilation shafts, with four planned for future sinking; two main surface magazines and four underground distribution stores; an anfo (ammonium nitrate and fuel oil) mixing shed and bulk emulsion storage facilities; and surface administration offices, change houses, surface workshops and a clinic.

Tailings are contained on site in a dedicated tailings storage facility, which has sufficient storage capacity to sustain the life-of-mine (LoM) mineral reserves.

Prospects: Exploration development is ongoing at the Mtshingwe shaft on 14 Level South. The Mtshingwe block has not been fully evaluated yet. Two holes were drilled at the end of 2017 and showed that the reef is more than 100 m below that of South Hill. It is in a graben with sympathetic faults in the orebody. More exploration holes are planned to be drilled in future.

Contact Details:
Sibanye-Stillwater
Tel +27 11 278 9600
Email ir@sibanyestillwater.com
Website https://www.sibanyestillwater.com