Regional Geology
The Iron Bridge Magnetite Operations are situated within the East Pilbara Terrane of the Pilbara Craton. Volcanic and volcanoclastic rocks of the Pilbara Super Group have been intruded by Archaean felsic granitoids, forming dome and keel type structures. Regional greenschist facies metamorphism and transpressional deformation have formed sub-vertical tight to isoclinal folds parallel to the granitoid contacts. Regional deformation is characterised by strike slip and reverse faulting.

The lease area includes two major volcanosedimentary formations, the Sulphur Springs and younger Soanesville Group. Sulphur Springs is a 2,500 m to 3,000 m steeply dipping sequence of ultramafic to mafic volcanics which are overlain by Pincunah deep marine BIF. The Soanesville Group is characterised by terrigenous clastic sediments.

Iron mineralisation at Iron Bridge occurs primarily within the Pincunah Member which outcrops across the entire project tenement. It is often masked by cemented caps of ferruginous weathered BIF, silcrete and detritus. A surficial weathered zone forms in upper (20 to 60 m) horizons dominated by maghemite and kenomagnetite, hematite and goethite after magnetite.

This unit forms an overturned north-south striking ridge through the North Star area of the deposit, dipping steeply westwards. Several vertical faults have been interpreted to rotate the Pincunah Member to northwest, parallel to the Mount Yule Granite complex in the north-west region of the project area.

The hanging wall of the Pincunah Member is the Kangaroo Caves Formation and is composed of BIF bands interlayered with laminated, micro to mesobanded shales and chert. BIF units are up to 15 m in thickness and occur most commonly immediately adjacent to the Pincunah Member contact, while the remainder of the formation is dominated by shales and cherts.

The footwall of the Pincunah Member consists of a sequence of shale and sandstone layers, termed the Eastern Shale and Quartzite, grading upwards into the sandstones and conglomerates of the Corboy Formation. Outcrop of the contact is marked by a high-relief zone of silicification before transitioning into white interbedded shale and sandstone beds with fine scale mesobanding and laminations.

Mineralisation
The main mineralised BIF zones within the Pincunah Member are described by the Iron Bridge Joint Venture (IBJV) as having a relatively limited mineral suite, with magnetite mineralisation overprinting the original lithology. Primary mineralisation occurs as disseminated grains and aggregates of magnetite micro-bands with subordinate gangue phases at concentrations of 30% to 60% magnetite (by volume). Lower grade mineralisation occurs within gangue dominant micro-bands with similar texture to primary mineralisation with a range of 1% to 30% magnetite.

Secondary magnetite occurrences are observed in association with quartz and stilpnomelane as well as monomineralic cross-cutting veins and generally forms coarser sub-euhedral grains.

The main zones of mineralisation at North Star and Glacier Valley is the Pincunah Member, which is comprised of sedimentary BIF with magnetite mineralisation, and which dips steeply to the west overall at approximately 70-80°.

The Pincunah Member mineralisation has been geologically defined into Western, Middle and Eastern units according to assay results and geophysical logging. Each unit is interpreted to be conformable within the Pincunah Member and adjacent stratigraphy and are intersected across the entire lease. The Western and Eastern units comprise the high-grade mineralisation domains, while the Middle zone is typically lower grade and often barren.

Geological interpretation of dimensions
- North Star comprises three distinct mineralisation style areas, North, Central and South, which are separated by interpreted fault zones. East Limb runs sub-parallel and to the east of North Star.

- The Northern part of North Star extends approximately 2.4 km in strike length, 200–400 m across strike and has been modelled to a vertical depth of approximately 600 m.

- The Central part of North Star extends approximately 1.9 km in strike length, 400 m across strike and has been modelled to a vertical depth of approximately 600 m.

- The Southern part of North Star extends approximately 1 km in strike length, 200 m across strike and has been modelled to a vertical depth of approximately 600 m.

- East Limb lies approximately 400 m east of North Star and is 2.3 km in strike length, 200– 400 m in width and is modelled to a vertical depth of approximately 200 m.

- Glacier Valley extends approximately 3.4 km in strike length, 200–300 m across strike and has been modelled to a vertical depth of approximately 600 m.

- West Star is approximately 3.5 km in strike length overall, of which 1.8 km strike length has been modelled. The mineralisation is typically 150–200 m across the strike and has been limited to a depth extent of approximately 200 m.

This is a standard truck and shovel iron ore operation located in the Pilbara region of Western Australia. Magnetite concentrate product will be transported through a slurry pipeline between Iron Bridge and Port Hedland.

The ore bodies planned to be mined in this study are bulk deposits and while some ore loss and dilution may occur along the edges, this edge dilution is accounted for in the regularisation process.

Metallurgical factors
The Iron Bridge flow sheet utilises HPGRs and air classification in a dry circuit, which differs from conventional magnetite operations, where ball mills are typically utilised in a wet circuit.

There are 8 x HPGRs and associated air classifiers in a crushing and grinding circuit, which has a cut point of ~100 microns. This dry circuit operation uses less energy and water than traditional ball mill circuits.

The technology being utilised is proven existing technology. The flowsheet does represent a departure from previous conventional norms however, the technology around the HPGRs is well proven in the cement clinker industry.

A pilot plant is operating on site and vendor test work has been undertaken to support the flow sheet unit operations.

The IB Port Facility will accept magnetite concentrate as a slurry from the North Star Mine, located approximately 110km south of Port Hedland. Upon arrival at the IB Port Fa ........