Mt Karara magnetite mineralisation is confined to a magnetite banded iron formation (BIF) lithological unit that occurs within a tightly folded and structurally disrupted northeast trending syncline. The Mt Karara syncline is characterised by a thick western limb dipping steeply to the east and a thinner and more structurally complex eastern limb that dips less steeply to the west, and it is the thick western limb that hosts most of the interpreted mineralisation. Where drilling has penetrated the base of the BIF, the syncline structure is interpreted to plunge steeply to the north. The drilling coverage has allowed the Mt Karara deposit to be modelled to a strike length of approximately 3km and the main mineralised zone has a width of approximately 500m. The BIF has been interpreted to extend vertically to depths of >700m below the surface.

Magnetite ore is mined from a large scale (12 m bench height) open pit mine in a traditional load and haul mining operation using conventional face shovels, large capacity (230 tonne) off-road haul trucks, a fleet of large diameter blast-hole drill rigs and a range of ancillary mobile mining equipment.

The project comprises a large, complex and fully integrated mining, processing and transport logistics operation designed to produce 8 Mtpa.

Magnetite ore known as Run-of-Mine (ROM) material is direct dumped by haul trucks from the mine into the primary crusher. Primary and secondary crushers crush the ROM ore to a product size of <60 mm. The crushed ore is then transferred to the Coarse Ore Stockpile (COS), which has a holding capacity of up to 500,000 tonnes of material for downstream processing.

Ore material from the COS is reclaimed by conveyor into a parallel train of two High-Pressure Grinding Rolls (HPGR’s), which grind the ore to a size of 4 mm or smaller. This ore material from the HPGRs is pumped in a slurry to a stage one magnetic separation. A high magnetic field allows separation of non-magnetic material to tailings. Magnetic material remains as a concentrate and is transferred to the primary grinding plant.

The primary grinding plant of four ball mills grinds the ore in slurry into fine particle sizes of <50 µm before further magnetic separation to produce a concentrated magnetite ore stream, with elevated Iron (Fe) grades of ~58%.

The mining proposal is to allow for the addition of mobile crushing activities to supplement the existing crushing circuit. This addition is necessary to maintain existing production levels, operating concurrently with the current primary crusher. There will be no increase to approved throughput or current production levels. The mobile crusher will be sited adjacent to the current Crusher Ore Stockpile (COS).

The crushing process will involve the ore feed hauled directly either from the Karara pit or from the COS stockpile, using existing mining fleet, that is then transported to the mobile crushing circuit for the commencement of the process.

Ore will be fed into the mobile crushing circuit via a CAT 980M Loader. The proposed mobile crushing circuit consists of:
I. Metso LT120 Jaw Crusher x 1
II. Metso LT300HP Cone Crusher x 2
III. Metso ST2.8 Scalping Screen x 1
IV. Metso ST4.8 Screen x 1

Ore mined from the Karara pit is processed via the beneficiation processing plant, which produces approximately eight million tonnes of magnetite concentrate per annum.

Upgrading to final product specification occurs in the flotation circuit. Concentrate is filtered to achieve moisture levels <10% and a final, premium concentrate product with Fe grades of +65%. Product is then transferred by rail to Karara’s Export Terminal at the Port of Geraldton.

Tailings material generated in the ore treatment process is filtered for dry tails stacking where possible, reducing discharge of tailings to Karara’s wet tailings storage facility (TSF), or tailings dam. This enables Karara to reduce water usage and minimise the environmental impact and footprint of tailings material.