Article, specimens and photos by Steve Sorrell unless noted otherwise.
Originally published in the Monthly Mineral Chronicles, Volume 3 Number 2, February 2020.
Introduction:
Broken Hill in New South Wales required, as was the case with many ore deposits, a way of converting silver lead ore into silver and lead. This meant the need for smelters. And wherever you have smelters, you have slag. Now the slag at Broken Hill is not that old, around 130 to 140 years, but that is still long enough to generate secondary minerals in cavities in the slag.
Smelting operations in Broken Hill itself were not carried on for a long period of time. Much of the ore was shipped elsewhere for processing.
The secondary minerals at Broken Hill are not abundant, but as it is an arid environment, and rainwater is likely to be the catalyst, that is probably not surprising.
I have included a number of historical photos of the smelting operations, and they have been tweaked for presentation (cleaning up, minor editing). The originals are available via links. The mineral photos are of specimens that were acquired from Jo Price’s micro collection. Jo is a Melbourne-based mineral collector.
Condensed Timeline:
The first smelter in region was erected at the Pinnacles Mine in 1885, followed by the Daydream the same year. The Daydream Mine was a short-lived one and in 1886, after only 10 months of operation, the smelter was closed down as there wasn’t enough ore to keep it running. Soon afterwards, the smelters were re-opened to treat the first production of ore from the Broken Hill Mine, as it had not started its own furnaces.
The first ore was smelted in Broken Hill by Broken Hill Proprietary (BHP) in 1886. Between 1888 and 1893, Block 14, South, Central and British companies smelted in Broken Hill. In 1894, Block 14 and Junction Mines sent ore to Port Adelaide for smelting. In 1898, the last smelter in Broken Hill ceased operations.
Smelting operations that began at Port Pirie in the mid-north of South Australia in 1889, as the nearest suitable seaport to Broken Hill, and were taken over by BHP in 1892. With other mining companies, BHP formed Broken Hill Associated Smelters in 1915 when the export of lead concentrates to Europe was interrupted during the First World War. BHP sold its shareholding in 1925.
Some companies sent ore to other places at various times, including Melbourne and Europe.
In the 1960s, the Central Mine (Sulphide Corporation) sent ore to a modern zinc smelter built In 1948 at Cockle Creek, New South Wales.
Minerals Recorded in the Broken Hill Slags:
The following list of secondary minerals was noted by Peter Elliott (1997):
Anglesite, Aragonite, Bechererite, Brochantite, Calcite, Caledonite, Cerussite, Connellite, Cumengeite, Cuprite, Gypsum, Hydrozincite, Jarosite, Ktenasite, Lanarkite, Leadhillite, Linarite, Malachite, Namuwite, Plumbojarosite, Posnjakite, Schulenbergite, Serpierite, Sulphur, and two unknown silicates.
Also noted as part of the slag in my specimens: Galena, Sphalerite.
References:
Elliott, P., 1997: Minerals of the Slags from Broken Hill, New South Wales. Australian Journal of Mineralogy, 3/1.
State Library of South Australia Digital Collection – https://www.catalog.slsa.sa.gov.au/
Other websites accessed: brokenhillheritagecity.com.au, www.eoas.info, Wikipedia.com, sahistoryhub.com.au, cbhresources.com.au, and minerva-access.unimelb.edu.au.
