The Jimblebar mining operation is located 40 km east of Newman at the southern margin of the Pilbara Craton, which is comprised of large granitoid domes and batholiths separated by down-folded sequences of the Pilbara Supergroup sedimentary volcanic and intrusive rocks.

The Pilbara region comprises a portion of the ancient continental Western Shield that dominates the geology of WA. The Western Shield is comprised of pre-Cambrian, Proterozoic and Archaean rocks. The Pilbara Craton dates back to the Archaean and includes some of the oldest rocks in the world. It is overlain by Proterozoic rocks deposited in the Hamersley and Bangemall Basins. The Hamersley Basin which occupies most of the southern part of the Pilbara Craton can be divided into three stratigraphic groups; the Fortescue, Hamersley and Turee Creek Groups. Of the three groups, the Hamersley Group is the most relevant to the Jimblebar mine.

The Hamersley Group formed approximately 2,300 to 2,800 million years ago, is approximately 2.5 km thick, and conformably overlies the Fortescue Group. It consists of a sequence of Banded Iron Formation (BIF), dolomites, shales, and acid volcanics, and is intruded by dolerite sills and dykes. It contains both the Brockman Iron Formation and the Marra Mamba Iron Formation, which provide most of the iron ore deposits in the Pilbara.

The Jimblebar mine lies within the Ophthalmia Fold Belt and comprises a series of east-west trending folded and tilted formations:
- The Jeerinah Formation comprising interbedded shales, siltstone, chert and quartzite, and partly forming the footwall of the South Jimblebar mine pits.
- The Marra Mamba Iron Formation, which forms the rolling ridgeline south of the Copper Creek valley. It comprises BIF, shales and siltstone and significant haematite mineralisation forming the South Jimblebar orebody.
- The Wittenoom Formation, comprising shales, cherts and dolomite. This formation has been preferentially eroded forming a major paleo-valley in the Jimblebar region which has subsequently in-filled with Tertiary sediments. Weathering has resulted in karst-like development in the dolomites of the Paraburdoo Member. The West Angela Member, a shale unit, is situated between the Marra Mamba Iron Formation and the Paraburdoo dolomite Member.
- Mount McRae shale and Mount Sylvia Formation comprising shales, BIF and cherts.
- The Brockman Iron Formation comprising a sequence of interbedded BIF, shales, siltstones and cherts and significant haematite mineralisation in the Dales Gorge and Joffre Members, forming the Wheelarra and Hashimoto orebodies. The formation is resistant to weathering and forms the east-west trending Wheelarra Hill and Hashimoto ridgelines.
- The Tertiary valley fill sediments which overlie the Wittenoom Formation comprise semi-consolidated and cemented alluvium, colluvium, detritals and secondary calcrete.

Wheelarra Hill deposits
Wheelarra Hill is comprised of units from the Brockman Iron Formation which form a prominent strike ridge rising 200 m to 300 m above the surrounding countryside, notably at the northern boundary of M266SA. This Brockman Iron Formation is composed of chert, ferruginous chert and minor shale bands.

The Weeli Wolli Formation outcrops to the north of the Wheelarra Hill ridge. It consists of interbedded BIF, chert and shale. Closely associated with this formation are rocks of the Woongarra Volcanics, which consist of partially metamorphosed igneous rhyolite and rhyodacite as sills or flows.

In the valley to the immediate south of the Wheelarra Hill ridge, sedimentary deposits are found, taking the form of partly consolidated and cemented colluvium in Tertiary valley fill deposits. These deposits are derived from dissection of the Proterozoic rocks.

Quaternary deposits occur as scree slopes, in drainage channels and associated floodplains that lie at the base of the Wheelarra Hill ridge. A number of north-west trending faults (including the Wheelarra Hill Fault) occur across the Wheelarra Hill ridge.

Hashimoto deposits
The Hashimoto deposits are orebodies that are laterally continuous, extensive and also form prominent ridges (albeit somewhat lower than Wheelarra Hill) along the northern boundary of M266SA. Structurally, the deposits are dominated by folding in the east with diminishing deformation effect towards relatively flat lying strata in the west.

Iron mineralisation at the Hashimoto deposits is contained within the Dales Gorge Member and the Joffre Member of the Brockman Iron Formation. Tertiary-aged detrital and recent alluvium/colluvium deposits are prevalent on the northern and southern sides of the Hashimoto deposits, and in some cases obscure the orebody. Where drilling has occurred below the water table, ore has been intercepted at depths exceeding 120 m.

Small to medium scale thrust faulting has been mapped in the Hashimoto deposits, and is interpreted as being related to the hinges of small-scale folds. Immediately to the east of Hashimoto H1 deposit is Jimblebar Creek which acts as a natural truncation of the orebody and also contains large volumes of detrital material. This creek is considered likely to represent the surface expression of a geological structure (probable fault) running between the Hashimoto H1 deposit and the H2 deposit.

South Jimblebar deposits
Iron mineralisation at the South Jimblebar deposit is primarily hosted within the Mount Newman Member, but also occurs regularly within the MacLeod Member and the base of the West Angela Member of the Marra Mamba Iron Formation. High grade mineralisation is not wholly continuous across the entire orebody, being rather patchy in some places, particularly at the western end of the deposit. Low grade mineralisation can also vary greatly across sections of the deposit. The thickness of mineralisation varies greatly across strike from less than 10 m to over 200 m.

The South Jimblebar deposit varies from simple straight dipping units to intensely folded units, with some small areas of significant faulting. Folding varies from moderately to steeply dipping strata towards the north that typically does not alter greatly across strike and does not appear to directly control mineralisation.

The Marra-Mamba Iron Formation is characterised by the intermittent occurrence of fibrous material, which includes the family of mineral broadly called asbestos. Asbestos is the common term used to describe naturally occurring fibrous materials which occur in silicate minerals from the serpentine and amphibole groups. Crocidolite or blue asbestos is part of the amphibole group and has the potential to occur in the South Jimblebar Marra Mamba Iron Formation deposits. The Wheelarra Hill ridge that contains the Wheelarra Hill and Hashimoto deposits is part of the Brockman Iron Formation, which does not contain fibrous material.

Major component of mining infrastructure at the Jimblebar Mine includes above and below water table mining of the Wheelarra Hill (WH123, WH4, WH56), South Jimblebar (Sylvania, Mindoona, Capricorn) and Hashimoto (H1234) deposits by conventional open pit methods (i.e. blasting of material then loading by hydraulic excavators and/or front end loaders into off-highway rear dump trucks for transport to the crusher or overburden storage areas [OSAs]).

Mining continues through conventional open cut mining methods, including drilling, blasting, and categorisation of blasted material into iron ore or waste rock.

WAIO open-cut mining uses face shovels, front-end loaders or backhoe excavators. The full bench is drilled and blasted for a 12 m height, sampled three times in 4 m increments and three 4 m flitches are then mined.

Ore and Waste haulage is done with both manually operated and autonomous haul trucks. Waste is hauled directly to the adjacent waste storage areas either ex-pit (on surface) or inpit. Waste material is also utilised as fill material for development works and rehabilitating the completed waste dumps.

Ore is hauled to the Run-of-Mine (ROM) pad where it is stockpiled and blended for ore quality before feeding to the crushers using loaders. Some of the ore suitable for blending is also hauled directly to the crushers.

Jimblebar processing hub started production in 2013 and currently has three primary crushers closer to mining sites and one central OHP with a nominal capacity of 71 Mtpa. In addition to the OHP, this processing hub has a stockyard blending facility and a train load out. This hub processes ROM ore sourced from both Brockman (BKM) and Marra Mamba (MM) deposits at proportions determined by the mine schedule.

The OHP recovers 100% mass of plant feed and produce both lump and fines ore types with a nominal split to lump stream of 30-40%.

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.

3 primary crushers, ore handling plant, train loadout, stockyard blending facility and supporting mining hub infrastructure (nominal capacity 71 Mtpa).