Iron mineralisation in the form of hematite rich sandstones is developed in the Yampi Member at or close to an unconformity with the underlying Elgee Siltstone on Koolan Island.

The Main Deposit comprises a tabular body of high grade mineralisation 1.8 km long which is between 25 m and 30 m thick and characterised by consistently high grades (>67% Fe) with very low levels of impurities. The deposit was developed by BHP and has been mined to a depth of 80 m below sea level.

Mining at Koolan Island will be by open pit method using conventional drill and blast, truck and excavator equipment. As the open pit is already established, there is minimal development work required and the ramp up to commercial production is anticipated to be achieved within 4 months of the recommencement of mining.

Ore Stockpile Area and processing plant
The OSA and processing plant are located to the east of the Main Pit. The OSA is used for storing unprocessed and processed ore. Product stockpiles are 8-10 m in height, and contain 100,000-250,000 t of product each. The stockpile yard is designed with a capacity of approximately 250,000 m3 of product, though this may be increased if required. The crushing plant consists of a two stage dry crushing and screening plant and stacker. No chemical processing of the ore is undertaken with the product and therefore it is considered a Direct Shipping Ore product.

The OSA and crushing plant comprise a combined area of approximately 32 ha. This includes a laydown area along with the OSA pad.