Irvine Island is located off the Kimberley coast of

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

in the

Buccaneer Archipelago The Buccaneer Archipelago is a group of islands off the coast of Western Australia near the town of Derby in the Kimberley region. The closest inhabited place is Bardi located about from the western end of the island group. , a new marine ...

. It is about northeast of Broome and north of

Derby Derby ( ) is a city and unitary authority area in Derbyshire, England. It lies on the banks of the River Derwent in the south of Derbyshire, which is in the East Midlands Region. It was traditionally the county town of Derbyshire. Derby gai ...

. Irvine Island is located near Koolan and Cockatoo Islands, on the same iron-mineralized rock formation. Irvine Island has a surface area of and is west of Cockatoo Island.

Geology and mineralisation

Irvine Island is composed of rocks of the Yampi Formation, a

Paleoproterozoic The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Ga), is the first of the three sub-divisions ( eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's ...

Statherian The Statherian Period (; grc, σταθερός, statherós, meaning "stable, firm") is the final geologic period in the Paleoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates a ...

-age sedimentary sequence of quartz sandstone, hematitic sandstone, feldspathic sandstone, siltstone, and hematitic conglomerate. Irvine Island, with two neighboring islands, Koolan and

Cockatoo A cockatoo is any of the 21 parrot species belonging to the family Cacatuidae, the only family in the superfamily Cacatuoidea. Along with the Psittacoidea (true parrots) and the Strigopoidea (large New Zealand parrots), they make up the orde ...

, is part of a belt of iron ore mineralization formed at the base of the Yampi Formation. The ore is mainly of

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

, with small amounts of

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...

. The ore grades laterally into hematitic conglomerate or hematitic sandstone. The sediments of the Yampi Formation were deposited near a shoreline where iron-rich heavy minerals were concentrated on a beach or nearshore bar by prolonged reworking. Mines on Koolan and Cockatoo Islands have been in production since 1951, while the deposits on Irvine island are still in exploration assessment.

Historical exploration

Australian Iron and Steel, a subsidiary of

BHP BHP Group Limited (formerly known as BHP Billiton) is an Australian multinational mining, metals, natural gas petroleum public company that is headquartered in Melbourne, Victoria, Australia. The Broken Hill Proprietary Company was founded ...

, explored for iron on Koolan,

and Irvine Islands from the early 20th century. Three mineral claims and two mining leases were granted to AIS on Irvine Island in the mid-1930s and early 1950s.Tengraph online system.
Department of Minerals and Petroleum.

References

{{coord, -16.076, 123.537, format=dms, type:isle_region:AU-WA, display=title Buccaneer Archipelago Iron ore deposits