Gravity Separation Development At Boddington Gold Mine
S.D. Hart , G.J. Hill
Presented at "Gravity Separation Technology for Gold Recovery", Aug. 26, 1994 Boddington, West. Australia
January 23rd, 1999
The Supergene/Basement Plant was constructed in 1990 and commissioned in early 1991. It was designed to process both copper-gold-silver anomalies within the laterite gold orebody and future hard rock ores.
The supergene plant incorporated control potential sulphidisation (CPS) and flotation ahead of CIL to remove a host of copper minerals. It operated in that configuration for 2 years at rates up to 350,000 tpa and average grades of 6.0 g/t gold and 1.2% copper. Gold recovery averaged 90.7% and copper recovery averaged 80.0% before the flotation circuit was decommissioned in March 1993.
Metallurgical testwork during the feasibility stages indicated that up to 30% of gold in plant feed could be recovered by gravity separation methods. It was also highlighted that significant improvements in overall plant recovery and reduced operating costs would be achieved by maximizing gravity gold recovery ahead of cyanidation. To achieve this, redesign and upgrade of the gravity circuit was necessary.
The Q.I.P. project concluded that the centre discharge Knelson Concentrator provided excellent metallurgical performance, a high level of security, robust equipment design and a fully automated control system.
In conclusion, the Knelson Concentrator improved gravity recovery which allowed a reduction in the blending requirements and a subsequent decrease in plant feed grade sensitivity. Higher grades can be processed without a detrimental effect on overall plant recovery or increased carbon stripping requirements, as the majority of the gold is now recovered to gravity concentrate.
Availability of the Knelson Concentrator has been high, averaging 99% since production started in March 1993. A successful preventative maintenance program and robust design features of the Knelson Concentrator have contributed to this excellent performance.
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