The Pilbara bioregion, where the Proposal (Mining Area C/South Flank) is located, is situated in the south-eastern comer of the Pilbara Craton. The cratonic basement comprises Archaean granite-greenstone and is unconformably overlain by the late Archaean to Early Proterozoic deposits of the Hamersley Basin. The Hamersley Basin can be divided into three stratigraphic groups: the Fortescue, Hamersley and Turee Creek groups. Of these groups, the Fortescue and Hamersley groups outcrop in the immediate area Mining Area C.

The Hamersley Group is seen throughout the Hamersley Basin and forms the outcrop of Mining Area C. It is a sedimentary sequence comprising banded iron formations (BIFs), shales and dolomites with minor felsic volcanics and intrusive dolerite dykes and sills. The group contains both the Brockman and Marra Mamba Iron formations, which together host most of the known major iron ore deposits in the Pilbara region. The six lowermost formations of the Hamersley Group that exist within the area are listed below in order of increasing age:

1. Weeli Wolli Formation.

2. Brockman Iron Formation. Ore mineralisation from the Packsaddle Range deposits is contained within the Brockman Iron Formation, composed of a sequence of interbedded Banded Iron Formation, shales, siltstones and cherts. The four members comprising of the formation are:
- Yandicoogina Shale Member (shale and BIF);
- Joffre Member (BIF with minor shale bands);
- Whaleback Shale Member (interbedded shale, chert and BIF); and
- Dales Gorge Member (interbedded BIF and shale).

3. Mount McRae Shale (graphitic and chloritic shales interbedded with BIF). The Mount McRae Shale (~30 m thick) consists of alternating bands of black carbonaceous shale and chert and is commonly capped with pyritic chert bands. The Mount McRae Shale forms the basal unit to the ore horizons in the Brockman Iron Formation and contains a limited enriched ore zone. BHP Billiton Iron Ore informally subdivides this lithology into five units based on lithology and pyrite content. Several zones within the unit contain abundant pyrite nodules, thus, the formation is commonly regarded as a significant AMD risk throughout the Pilbara region.

4. Mount Sylvia Formation (shale, dolomite and BlF bands).The Mount Sylvia Formation (~2.5 Ma) has a thickness of ~50 m in the vicinity of the town of Newman, WA, and consists of three BIFs separated by interlayered shale and dolomite as well as small amounts of chert.

5. Wittenoom Formation. The Wittenoom formation is located stratigraphically above and is younger than (2.6 – 2.5 Ma) the Marra Mamba Formation. The Wittenoom Formation has been deeply eroded in the development area and is mostly covered by Tertiary Detritals. The formation is predominantly comprised of calcareous and manganiferous shales, cherts and dolomite and includes the following members comprising:
- Bee Gorge Member (calcareous shale and dolomite);
- Paraburdoo Member (dolomite – karstic in part); and
- West Angela Member (manganese-rich shale with minor BIF and chert bands).

6. The Marra Mamba Iron Formation consists of:
· The lowermost Nammuldi Member (approximately 80 m thick) which includes thick bedded, poddy cherty BIF interbedded with thin shales.
· The MacLeod Member (approximately 75 m thick) which includes BIF, cherts and carbonates with numerous interbedded shales.
· The upper Mount Newman Member (approximately 65 m thick) which includes podded BIF with interbedded carbonates and shales. The Member has been sub-divided by BHP into three sub- members based upon shale band content to allow for detailed modelling and estimation; lower N1, central N2 and upper N3.

Iron ore mineralisation within Marra Mamba hosted deposits occurs as either martite-goethite or martite-ochrous goethite formed primarily by supergene enrichment processes. The Mount Newman Member is the main mineralised horizon within the formation although lesser amounts of mineralisation can be found in the Nammuldi and MacLeod Members and within the overlying West Angela Member shales of the Wittenoom Formation.

Mining Area C, South Flank, Yarrie and Nimingarra are open-cut.

Ore is crushed, beneficiated (where necessary) and blended at the processing hubs – to create lump and fines products that are transported along the Port Hedland–Mt Newman rail line to the Finucane Island and Nelson Point port facilities at Port Hedland.

2 primary crushers, 2 ore handling plants, stockyard blending facility and train load out (nominal capacity 60 Mtpa).