Irvine Island
Geology and mineralisation
Irvine Island is composed of rocks of the Yampi Formation, a Paleoproterozoic Statherian-age sedimentary sequence of quartz sandstone, hematitic sandstone, feldspathic sandstone, siltstone, and hematitic conglomerate.
Irvine Island, with two neighboring islands, Koolan and Cockatoo, is part of a belt of iron ore mineralization formed at the base of the Yampi Formation. The ore is mainly of hematite, with small amounts of magnetite. 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, explored for iron on Koolan, Cockatoo 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.
References
- ^ Oxford, Anna (February 2009). "Appeal Report, Irvine Island Iron Ore Exploration Programme – Phase II" (PDF). Perth, WA: Office of the Appeals Convenor. Retrieved 9 November 2020.
- ^ "Status Performance Assessment: Biodiversity conservation of Western Australian Islands" (PDF). Government of Western Australia. 1 April 2010. Archived from the original (PDF) on 14 March 2018. Retrieved 31 August 2014.
- ^ Tyler, I. M.; Griffin, T. J. (1 December 1993). "Explanatory notes on the Yampi 1:250 000 Geological Sheet, Western Australia". 1 :250 000 Geological Series-Explanatory Notes. Pert, WA: Geological Survey of Western Australia: 23. ISSN 0729-3720. Retrieved 9 November 2020.
- ^ Tengraph online system. Department of Minerals and Petroleum.