6) Rock Crusher Stamper Head

Australian Gold Mining - Gold Extraction Method

Activity - Ore Crusher Demonstration
6)  Rock Crusher Cogs Closeup

To separate the gold from the ore collected by the diggers in the mine tunnel, ore first had to be crushed by a series of hammers in the stamper head.

The crushed ore was then washed over copper plates that had been treated with cyanide and tinned with "quick-silver" (mercury). Mercury has a chemical affinity to gold, hence catches it. The resulting  putty like mixture was then scraped off the copper plate placed into a crucible and heated to evaporate the mercury until only the gold remained. Sometimes retorts were placed over the crucible to recycle the toxic mercury and cyanide.

This method of extraction was used for many years although it was generally accepted that it was only 60% effective.

This 10 head stamper was originally manufactured by Thompson & Co. of Castlemaine, probably from English pig iron that was used as ballast by ships. The stamper was first used in the Victorian Goldfields. It was used during the Araluen gold rush then dismantled and rebuilt at Old Mogo Town by Tom Dunne of H Dunne & Sons Mining Engineers.

The stamper heads are now maintained with the help of volunteer engineers and Walters Maintenance of Goulburn NSW. Many such ore crushers can still be found discarded at the old gold mine sites out in the Australian forests.

There are very few 10 head stampers still in working order. In order to preserve the machinery, the stamper heads now thump onto rubber matting, rather than onto quartz rock.

Parts of our mining display have been generously donated by the Department of Mines from Bimbimbie Mine after its recent closure.

Working at the gold ore crusher was not a good career choice because the high noise level tended to cause deafness. Lung diseases caused by the cyanide and mercury were quite common.

Mercury also caused mental illness, in the same way as the felting industry, where manufacturers of felt hats often went "Mad as a Hatter."

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