Sishen mine is host to a large haematite orebody (±14km by 3.2km by 400m). Its lump ore is highly valued by steelmakers. Sishen’s lump to fine ratio is of the order of 60:40, while the global average is 30:70.

The iron ore deposit at Sishen Mine is one of a number of genetically related high-grade haematite deposits situated in the Sishen – Postmasburg area. Superior-type banded iron formations (“BIF”) of the Transvaal Supergroup crop out along the western margin of the Kaapvaal craton in the Northern Cape Province. These iron formations can be traced as a prominent range of hills in a broken arc for some 400km from Pomfret in the north, to Prieska in the south. The bulk of the hematite mineralisation is found in the vicinity of Postmasburg and Sishen Mine. Within this sub region, iron ore and associated lithologies of the Transvaal and Olifantshoek Supergroups crop out intermittently along an arcuate belt for 60km.

The ores at Sishen Mine are composed of hematite and specular hematite with minor to trace amounts of limonite. Four distinct ore types can be classified. Each has unique chemical, physical and metallurgical properties. The genesis of each ore type has been influenced by regional tectonism and the preservation of each orebody is primarily determined by local geological structures. The Laminated and Massive Ore are the most important sources of high grade, lump ore in the region. The upper portions of the Asbestos Hills Subgroup comprise fairly undisturbed, thinly laminated, hematite ore which grades upward into thickly bedded, contorted and even massive ores. Breccia ores comprise a chaotic arrangement of very angular and poorly sorted fragments of laminated and massive ore types, cemented by specular hematite. The breccias fill palaeosinkholes developed in the carbonates of the Campbellrand Subgroup. Angular fragments of BIF and some argillitic material are also found in the collapse breccia. Specularite is very common in the porous breccia matrix.

Sishen mine is a highly-mechanised, open-pit mine with processing facilities. Operations are conducted 24 hours a day, 365 days a year.

Mining benches are cut at 12.5m intervals although smaller equipment has been introduced to enable the mining operation to mine more selectively from the bench and flitches. The mining operation is conducted using a large fleet of conventional open pit mining equipment comprising blast hole drilling rigs, electric face shovels, and 170t and 190t off-highway trucks supported by appropriate ancillary mining equipment. Where appropriate, electric trolley assist for truck haulage is used improving the up-hill truck speeds on in-pit haul roads and roads to the waste dumps. A small proportion of the waste rock can be free dug (16%) but the majority of the rock to be mined requires drilling and blasting. The ore material consists of haematite in enriched banded iron formation.

Sishen mine beneficiates its high-grade Ore Reserves by means of a DMS plant and its medium-grade Ore Reserves by means of a Jig facility to produce Saleable Product according to required client specifications. The mine furthermore commissioned a small-scale ultra-high dense media separation plant in 2016 to treat a portion of the Jig plant discard and produce Saleable Product. The jig plant at Sishen mine is the largest of its type in the world.