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.

At Sishen Iron Ore Mine, high-grade hematite ore is extracted from specific stratigraphic units belonging to the Palaeo-Proterozoic (~ 2400 million years (Ma)) Transvaal and (~ 2070 Ma) Olifantshoek Supergroups, respectively.

The Superior-type banded iron-formations (BIF’s) of the Transvaal Supergroup lithologies were deposited in two related basins, one in an extensive continental shelf environment and the other in an intra-continental sea, both situated on the Kaapvaal craton.

Sishen mine is situated on the northern extremity of the Maremane anticline. At this location the lithologies strike north-south and plunge from the centre of the anticline in a northerly direction.

The bulk of the resource comprises highgrade, laminated and massive ores belonging to the Asbestos Hills Subgroup. The ore bodies are intensely folded and faulted. Dips vary according to local structures, but at Sishen, a regional dip of 11° in a westerly direction prevails.

Sishen Mine is a conventional open pit mining operation applying a pushback deployment strategy. The distinctive mining areas are North Mine (G80 and G50), Middle Mine, Dagbreek, Vliegveld, Far South and Lyleveld. Material is drilled, blasted, loaded by electric and diesel (rope and hydraulic) shovels and hauled by trucks to either the primary crusher, high-grade or low-grade stockpiles or waste dumps. Benches are 12.5 m high. The ore from the opencast pit is transported to the beneficiation plant where it is crushed, screened and beneficiated through dense media separation and Jig technology.

The current mining process entails topsoil removal and stockpiling for later use during the waste dump rehabilitation process, followed by drilling and blasting of waste and ore. The waste material is in-pit dumped where such areas are available or hauled to waste rock dumps. The iron ore is loaded according to blend (grade) requirements and hauled to designated run-of-mine buffer stockpiles or the beneficiation plants, where it is crushed, screened and beneficiated.

Iron ore mining operations.
Mining started in outcrop and shallow ore areas along the north to south strike of the ore body and is generally progressing in a westerly direction along the dip of the ore body, with the mine pit becoming increasingly deeper towards the west. Four types of hard iron ore, namely massive, laminated, conglomerated and brecciate iron ore are mined. Blast hole drilling is a continuous process and blasting is done once a day, typically in the early afternoons between 12h00 and 14h00, at each of the active mining areas within the mine pit.

Vliegveld West Satellite Pit (Sishen 543 Prospecting Right Area - 1021/2007 PR).
The Vliegveld West satellite pit is situated south of the Dingleton town and is part of the current mining right area. It extends onto the Sishen 543 prospecting right area and has a reserve of 14.7 Mt with an average JIG beneficiated Fe grade of 65.8%. Vliegveld West is mined from 2020 onwards in the lifeof- operation schedule.

The Doornvlei Satellite Pit (Gamagara 541 Prospecting Right Area - 319/2006 PR). Doornvlei is situated west of the Dingleton town and has an additional resource of 37.7 Mt with a high average DMS Beneficiated Fe grade of 66.3%. Doornvlei plays an important role to enhance the product grade in the life-of- operation schedule.

Parsons Satellite Pit (Sishen 543 Prospecting Right Areas - 1021/2007 PR and Parsons 564 - 320/2006 PR).
The Parsons Satellite pit is planned south of the current Sishen pit and has a speculative resource, categorised as a 15.4 Mt deposit, with an average in-situ Fe grade of 64%. The importance of the Parsons Satellite pit is that it can significantly contribute to the production schedule toward the end of the life- of-operation and may develop into a significant production area in the future. The geological confidence in the Parsons deposit needs to be improved by exploration and in-fill drilling.

An additional primary crusher (UPC) will be required for the processing of some of the material as the existing DMS and JIG plant crushers do not have capacity to process all of the additional ROM. A-grade and/or C-grade ore shall be crushed by the existing primary and secondary DMS crushers which have capacity of 26 Mtpa. The UPC will serve to crush additional feed material to the UHDMS and this could include both A-grade, B-grade & C-grade as well as lower grade material. The crushed material from these crushers shall then be delivered to the existing DMS tertiary crushers and the DMS stockpile. The material from the DMS stockpile is fed into the Washing & Screening Plant.

Processing run-of-mine through two primary processing facilities (DMS plant and Jig plant) with a combined operating capacity of 34.7 Mtpa Saleable Product. A smallscale UHDMS plant has been commissioned in 2017, which treats some of the Jig discard material.

The screened ore size fractions are beneficiated through either:
• a ferro-silicon DMS plant, where most of the high-grade run-of-mine is treated, or
• a Jig plant where most of the medium-grade run-of-mine is treated, with two UHDMS modules treating some of the Jig discard to recover more Saleable Product.

Plant slimes are not beneficiated and are pumped to evaporation dams while the DMS and Jig (and UHDMS) discard material is stacked on a plant discard dump. Four iron ore products (conforming to different chemical and physical specifications) are produced. The product is reclaimed from product beds and loaded into trains, to be transported either to local steel mills (domestic market) and Saldanha Bay (for export market), from where it is shipped together with Kolomela product and sold to international Clients under three KIO branded products referred to as premium Lump ore, standard Lump ore and standard Fines ore.

Ultra-High Dense Media Separation (UHDMS) is a recently proven technology that will allow for the processing of future low-grade material (particularly C-grade material) originating from the ongoing mining operations as run of mine (ROM) as well as some of the low-grade material that has historically been dumped on site due to the lack of available technology. C-grade material refers to lower grade ore types containing between 40% and 48% iron.

The C-grade material to be processed will be sourced from the ROM (is part of the hanging and footwall that are already included in the mining sequence) as well as surface stockpiles. Cgrade material arising from the ROM since January 2016 has also been stockpiled separately on some of the waste rock dump areas with the anticipation that it could be processed through the future UHDMS plant. The anticipated ROM of C-grade material is 7-26 Mtpa.

DMS Upgrade.
The existing DMS Processing Plant at Sishen is to be upgraded to allow for the incorporation of UHDMS which will allow for the co-processing of both high (A-grade) and low (C-grade) grade material. The JIG plant will continue to process the B-grade material and some of the A- grade material due to a revised feed strategy. The current DMS plant comprises the following sections:
- Washing & Screening Plant;
- A Coarse Drum Plant;
- A Medium Drum Plant;
- A Coarse Cyclone Plant;
- A Fine Cyclone Plant;
- An Up-Current Classifier (UCC) Plant.

The DMS components at the existing DMS Processing Plant will be converted to UHDMS processes by the replacement of the drums currently used in the beneficiation process with cyclones; and also modifying the existing media density circuits as well as crushing circuits. The following changes are currently envisaged for the existing DMS Plant:

- The existing Washing & Screening Plant at the DMS Plant will be modified. This will involve the modification of the screen panel sizes.
- The material from the Washing & Screening plant shall be sent to the Quaternary Crushing Plant to crush the material as required by UHDMS technology.
- A new oversize conveying system will be erected from the existing Washing & Screening Plant to the existing conveyor feeding the stockpiles ahead of the exiting Quaternary Crushing Plant.
- No changes will be made to the Quaternary Crushing Plant.
- The crushed material from the Quaternary Crushers shall be sent to the Quaternary Screening plant which will separate the material into three size fractions. The existing Quaternary Screening Plant will be modified to Screen Quaternary oversize material after Quaternary Crushing.
- Upgrade of the existing Drum Plant by removing drums and replacing with cyclones. The Drum Plant will be converted to a coarse UHDMS Plant.
- Development of a new conveyor from the Quaternary Screening Plant to the existing Drum Plant.
- Upgrade of the existing Coarse and Fine Cyclone Plant involving upgrades to specific densification systems.
- The existing Coarse Cyclone Plant will be converted to the Fine UHDMS Plant.
- The existing Fine Cyclone Plant will be converted to the Superfine UHDMS Plant.
- Development of a new conveyor from the Quaternary Screening Plant to the existing Fine Cyclone Plant.
- The UCC Plants will be modified to treat grits, if required.
- Feeders at the in-pit stockpile will be replaced next to the DMS Tertiary Crushers.
- Modification of the product transfer, common lump product and plant discard conveyor.
- Two new conveyors at the Discard Transfer Station and a new Discard Emergency Stockpile at the foot of the existing Discard Dump.