The deposit contains both detrital and bedded-hosted iron mineralisation.

The detrital portion of the deposit is a Brockman Iron Formation-derived detrital iron deposit overlying the bedded Dales Gorge Member of the Archean Brockman Iron Formation.

The bedded-hosted portion of the deposit contains iron mineralisation which occurs as a highphosphorus Brockman Iron deposit with a weathering overprint.

The mineralisation extends 10 km along strike in an East – West direction, up to 1 km perpendicular to strike in a South - North direction and to a maximum depth of 230 m below the current topographical surface. The hydrated and detrital domains are mostly continuous with the pod-like bedded domains and the average depth varying.

Development of this Mineral Resource assumes mining using standard Rio Tinto Iron Ore equipment and methods similar to other Rio Tinto Iron Ore operations. The assumed mining method is conventional truck and shovel, open pit mining at an appropriate bench height. Mining practices will include grade control utilising blast hole data.

There are two existing dry crush and screen processing facilities and one existing wet desliming processing facility to which Brockman Syncline 2 – East Detrital ore could be fed. Product prediction regressions for both dry and wet processing routes are assigned to the designated domains, based on the most appropriate available metallurgical data generated from PQ-3 cores, WDC, winzes and production data.

The dry plants crush and screen the ore into dry lump and fines products.

The wet desliming plant scrubs, screens and deslimes the ore to produce washed lump and fines products. The plant was commissioned in early 2015.