Cockatoo Island Mine, Buccaneer Archipelago, Derby-West Kimberley Shire, Western Australia, Australia

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An iron mine closed before 1985. Owned by Broken Hill Proprietary.

Located 140 kilometres north of Derby in the Buccaneer Archipelago.

Iron ore was discovered here in 1880. It first came to the attention of pealers, who used iron stone from the beaches as ballast for their boats. Large scale mining of the iron ore was started by BHP in 1951. The mine closed in 1984, after the ore body had been mined to sea level. One side of the island was composed of almost pure hematite. Workers at the mine claimed you could weld the rocks together.

From the 1990's to present (2012),several small companies have been involved in re-opening the mine. A sea wall was built and mining is happening below sea level.

Nearby Koolan Island has also been mined for iron ore. Small scale mining started in 1907. A larger mine was established in 1936 by Yampi Sound Mining Co, exporting iron ore to Japan. The Federal Government closed the mine in 1938, as part of its embargo on exports to Japan at the time. The mine was re-opened in 1946, to supply the State Government's charcoal iron plant at Wundowie, near Perth. BHP took over the mine in the late 1940's, closing in 1994.

The mine was re-opened in 2006, and is presently operated by Mt Gibson Iron. Unfortunately, an extensive marine ecosystem which had developed in the flooded pit was removed.

Irvine Island is 5 kilometres west of Cockatoo Island, and holds high grade hematite deposits, however it has never been mined, due to opposition from the local indigenous people.

Mining is concentrated in the high iron ore grades found in the Yampi Member. It forms a band within layers of sandstones. The Yampi Member is found in the upper levels of the Pentecost Sandstone, and contains dark grey hematite, magnetite quartz sandstone, and quartz pebble conglomerate. At Cockatoo Island the Yampi Member is virtually pure hematite.

The Yampi Member is 1880-1760 Ma. It shows as matrix hematite, and hematite grains in sandstone, minor feldspar sandstone, numerous thin phyllite and occasional basal conglomerate, all overlying the Elgee Siltstone.

At Koolan Island mineralisation covers 2000 metres, and up to 30 metres thick, dipping 45-60 degrees south. It was mined from 180 metres to sea level. It contains hard and friable hematite, with insertions of hematite sand, and hematite conglomerate. Alot of the hematite is porous, having undergone de-silicification, thereby increasing the grade of iron.

The mines can be seen by air from sea plane from Broome and Derby on the way to nearby scenic attractions. Expensive small scale luxury cruises also take place in the area.

Mineral List

Goethite

Hematite

Quartz

3 entries listed. 3 valid minerals.

References

External Links