Iron Knob is a town in South Australia on the Eyre Peninsula immediately south of the Eyre Highway. At the 2006 census, Iron Knob and the surrounding area had a population of 199. The town obtained its name from its proximity to large deposits of iron ore, most notably Iron Monarch which outcropped prominently from the relatively flat, surrounding landscape.
History
Iron ore was first mined by the Broken Hill Proprietary Company at Iron Knob for use as flux in lead smelters at Port Pirie. The iron ore proved to be of such high quality (upwards of 60% purity) that it led to the development of the Australian steel industry. It supplied iron to Newcastle for and steel works established at Newcastle and Port Kembla in the 1910s and 1920s and Whyalla in the 1930s. The iron ore was transported by railway to Whyalla where it was either smelted or dispatched by sea.
21% of the steel required for the construction of the Sydney Harbour Bridge was quarried at Iron Knob and smelted at Port Kembla, New South Wales. The remaining 79% was imported from England.
In the 1920s, iron ore from Iron Knob was exported to the Netherlands and the United States of America. Prior to World War II, iron ore from Iron Knob was also exported to Japan. In the financial year 1935-36, 291,961 tonnes of ore from Iron Knob was shipped there via the seaport of Whyalla.
This became a matter of some controversy in the late 1930s due in part to Australia's known reserves at the time being limited to Iron Knob and Yampi Sound in Western Australia. Japan was also considered an 'aggressor' nation following acts of war against China in 1937. Waterfront workers and seamen protested against the export of iron ore to Japan, leading to strikes and arrests. Iron ore from Iron Knob was also exported to America, Germany and Great Britain during the 1930s.
Additional deposits of iron ore were developed by the Broken Hill Proprietary Company further south along the Middleback Range, including Iron Princess, Iron Prince (1932), Iron Baron, Iron Knight, Iron Duchess and Iron Duke.
In 1937, output from the Middleback Range, mostly from Iron Monarch was estimated at 2 mtpa. In 1939, it was referred to in England as the highest grade deposit of iron ore known in the world. In 1943, the iron Knob deposit was still delivering an average ore great of 64 percent metallic content. In 1949, 99% of Australian demand for iron ore was met by supply from Iron Knob and associated mines in South Australia, having risen from 95% in 1943.
Quarrying for iron at Iron Knob and Iron Monarch ended in 1998. When the mine closed down in 1998, the town's population reduced to 200. Iron Knob was under threat of becoming a ghost town. However, due to rising prices of housing elsewhere, the town has attracted new residents seeking low cost residences. A home could be purchased for approximately A$35,000–70,000 and vacant land could be purchased for less than A$15,000.
In 2010, Onesteel (now Arrium Ltd) announced that it would return to Iron Knob to reopen the Iron Monarch mine. The Iron Monarch mine was prepared for reopening by Arrium Ltd in 2013. As of 2015, both Iron Monarch and Iron Duke continue to produce iron ore for export and for smelting at the Whyalla steelworks.
Transport
In the early days of mining at Iron Knob, ironstone was carted by oxen to Hummock Hill (now known as Whyalla). Approximately 300 tonnes was delivered in a good week. Construction of a private railway greatly increased transportation rates and by 1939, 9,000 tonnes of ore was delivered daily to Whyalla by rail. Later trains carried 2000 ton loads.
Ships operated by the then BHP company were similarly named Iron This and Iron That, some of which were built by the company at the Whyalla steelworks.