The Cloudbreak, Christmas Creek and Kutayi deposits lie within the Chichester Ranges, in northern Western Australia. Iron mineralisation is hosted by the Nammuldi Member which is the lowest member of the late Archaean aged Marra Mamba Iron Formation (MMIF). The Nammuldi Member is characterised by extensive, thick and podded iron rich bands, separated by equally extensive units of siliceous and carbonate rich chert and shale. The Nammuldi Member in the Chichester Range is interpreted to be up to 60 metres in true thickness. Underlying the Nammuldi Member rocks are black shales and volcanic rocks belonging to the Jeerinah Formation. Extended periods of tectonic activity have variably folded and faulted these rocks, together with weak metamorphism. Subsequent erosion and hardcapping or lateritic processes have altered these rocks, and present outcrop of Nammuldi Member represents a ridge of lowlying hills (relief up to 30 metres) throughout the prospect areas. These ridges are recognised as the Chichester Ranges.

Drilling within the prospects has proved that the Nammuldi target horizon extends below cover away from the hills. In these regions (recognised mineralisation has been intersected more than 6 kilometres from the outcrop) the target iron formation can be overlain by Tertiary age colluvium and alluvium (younger than 65 Million years). This colluvium can contain both cemented and un- cemented detrital products of iron enriched material, BIF, chert and shale within a matrix of finer grained sediments (including clays). Percolation of groundwater through the weathering profiles has resulted in precipitation of both calcrete and ferricrete creating resistant horizons within the extensive regolith. More proximal to the Fortescue Marsh to the south, the Tertiary sediments become finer grained and more clay dominant, with some recognised calcareous zones.

Structure
The structural geology of the area is predominantly concealed with limited outcrop exposure. However, small scale faulting and folding (metre offsets) can be observed in some outcrops, and larger-scale faults are interpreted from aeromagnetics and regional mapping, plus drilling results. There is currently no evidence to suggest that the faulting or folding crosscuts the mineralisation. In places faults may be the conduit for the mineralisation (hypogene model).

Iron Mineralisation Styles
The mineralisation is characteristically hematite and goethite (with variable degrees of alteration between these minerals). Main gangue minerals are kaolinite, quartz and gibbsite, with minor gangue including carbonates, either calcite or dolomite.

Iron is enriched from the parent rock (Banded Iron Formation, BIF) by processes of supergene and, or hypogene enrichment. In both processes, the original iron is present as magnetite bands within the BIF (iron banded with cherts and lesser carbonates), and oxidation of the magnetite to hematite and goethite occurs. Contemporaneous with the iron enrichment, the original gangue minerals are partially to fully leached out or replaced by iron minerals, giving an overall increasing content of iron minerals depending upon the degree of enrichment. A volume loss of up to 35% can occur with enrichment due to loss of gangue minerals.

Microplaty hematite (MplH) is recognised in varying degrees throughout Fortescue’s Chichester Range deposits. This is interpreted to occur due to hypogene enrichment of the MMIF in proximity to tectonic structures (faults or tight folds), which have allowed upward fluid flow, and low- grade metamorphism of the parent rock, resulting in extensive hematite mineralisation.

The majority of the iron mineralisation is martite-goethite resulting from supergene enrichment of a BIF substantially rich with magnetite (oxidised to martite) in the parent rock.

Hardcapping (ferricrete development) of portions of the mineralisation has been identified in mapping and drilling. This process, formed at latter stages of geological development (Tertiary), has changed the physical and geochemical properties of the upper portions of the mineralisation (up to 10 metres thickness). Hardcapped material has a higher density being pervasively cemented by goethite, commonly has vitreous goethite included in the matrix, and can be quite vuggy. An
associated increase in gangue content may be seen in hardcap due to the near surface processes of ferricretisation.

Mineralization in the Christmas Creek deposit occurs over an area approximately 39 kilometers along strike and up to 9 kilometers in width, from the surface to a depth of 117 meters. There are four types of mineralization at Christmas Creek: hardcap mineralization, Nammuldi Member mineralization (greater than 50% iron cut-off grade), higher grade Nammuldi Member mineralization (greater than 57% iron cut-off grade) and CID.

Drill and blast
Drilling and blasting is used to allow areas of hard rock overburden to be removed. Drilling and blasting is undertaken in accordance with current operational procedures, which generally incorporate the following steps:
1. A series of holes are drilled into the rock.
2. The holes are filled with explosives and detonated.
3. The rock breaks up or collapses after detonation and the rock rubble is then removed.
4. The cleared rock face is ready for drilling and the steps are repeated.

Strip Mining
Mining will continue to be undertaken using the same mining methodology currently in place, consisting of conventional truck and shovel mining and strip mining. Typically, strip mining involves pits being developed in thin strips, around 150-200 m wide by 800 m long. Each mining area is mined to suit a particular set of constraints and requirements.

When mining commences in a new pit, the overburden is removed from the first two adjacent strip and placed just beyond the ore body limits close to the last strip to be mined in the sequence. Ore is then mined from the first strip.

When the ore in the second strip is removed, removal of overburden from fourth strip commences and material is backfilled into the void of second strip, while concurrently mining the ore in the third strip. This process progresses through the mining area.

When the ore from the penultimate strip is removed, waste from the first strip (stockpiled nearby) is backfilled into that void. When the ore from the last strip is removed, the remainder of the stockpiled waste from the first two strip is backfilled into the final void. Completed pits are backfilled at minimum to the pre-mining groundwater level. Waste rock and overburden material are generally removed using a combination of shovels, excavators and trucks. The majority of overburden is used to backfill completed pits.

Remote Crushing
An RCH currently operates approximately 6.5 km east of the main processing facilities at Christmas Creek. The RCH sizes the mined material to prepare it for processing in the OPF (ore processing facilities). The RCH consists of:
- ROM bin
- mineral sizer
- gyratory crusher
- crushed ore vault.
Once material has been crushed, it is transported to OPF2 by an overland conveyor.

Ore Processing
Ore stockpiling and Management
ROM pads are used to store ore according to ore grade, and to allow some blending of ore to occur prior to processing. Small ROM pads are located adjacent to active pits. Ore is either trucked directly from the pit or from the small ROM pads to one of the two major ROM pads at Christmas Creek located directly north of the RCH and the OPFs.

Mobile Crushing and Screening
Mobile crushing and screening facilities operate as required at Christmas Creek and used for a number of purposes, such a ........