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.

There are no changes required to the existing processing facility at Koolan Island. Regular maintenance checks have been conducted during the care and maintenance period, together with a major overhaul of the primary crusher.

The metallurgical characteristics of the Main pit ore are well known from previous mining and processing from 2007 to 2014, and offtake contracts remain in place for all of Koolan Island's planned future production volumes.