The Victorian gold rush of 1851 to 1896, produced over 61 million ounces of gold. In those days, head grades were high and recoveries were low by today's standards. The principal method of comminuting hard rock ore to fine particles was by stamp mills which pulverised rock (rather than grinding it) within a wet mortar box. These machines reduced the 8" to 12" feed rocks to particles of less than 2mm diameter, which liberated a significant proportion of the gold. Once pulverised, the gold laden slurry stream flowed down the declined copper plate, smeared with mercury which attracted the gold particles and formed a mercury-gold mixture known as amalgam.
This process, which was replicated over many of the Victorian gold fields, left millions of tonnes of residues called "battery sands". Many of which still exist today and still contain gold. Once such dump of battery sands near Ballarat, comprised 100,000 tonnes of sands running at an average grade of 2.6g/t amounting to 260kg or 8,360 ounces of gold.The key objective of the project was to execute an R&D exercise by assessing the relocatable concept's performance, viability and commercialisation potential. The design, construction and commissioning of the plant was provided by a third party, whilst Atom focussed on assessing layout flexibility, component functionality process improvement and commercialisation potential.Although the simple process used, was essentially a "batch fed modified CIP" running at just 10 tonnes per hour, it provided Atom with operational insight into the importance of selecting the appropriate material reclaim methodology, ensuring plant mobility criteria were implemented at the design stage. Optimising process flow and understanding the nuances of complex environmental legislations involved in tailings disposals.
