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Newcrest Mining's Cadia Valley copper-gold operations are located about 25 km from the city of Orange in New South Wales, Australia. The operations consist of the the Ridgeway high-grade and Cadia Hill low-grade concentrators. Both use Outokumpu flotation cells, and the results of recent modifications to the cells are described. Modified Outokumpu SkimAir rotors and stators were fitted at both plants, and their longer part life reduced maintenance costs. Outokumpu ForceFloat mechanisms were tested in the scavenger circuits of both concentrators, which improved the recovery at the Cadia Hill plant. There was no significant change at Ridgeway. The results of the modifications are presented, showing the improvements in terms of mineral processing parameters, equipment life, and maintenance costs., Newcrest Mining's Cadia Valley copper-gold operations are located about 25 km from the city of Orange in New South Wales, Australia. The operations consist of the the Ridgeway high-grade and Cadia Hill low-grade concentrators. Both use Outokumpu flotation cells, and the results of recent modifications to the cells are described. Modified Outokumpu SkimAir rotors and stators were fitted at both plants, and their longer part life reduced maintenance costs. Outokumpu ForceFloat mechanisms were tested in the scavenger circuits of both concentrators, which improved the recovery at the Cadia Hill plant. There was no significant change at Ridgeway. The results of the modifications are presented, showing the improvements in terms of mineral processing parameters, equipment life, and maintenance costs.

Projects are described that have contributed to improving Au and Cu recovery by 3%-4% at the Cadia Valley operations in New South Wales. These have included the installation of a 355 kW stirred-media detritor to create a regrind circuit, installation of froth crowders on the scavenger circuit, installation of a gravity concentrator as part of the regrind circuit to improve Au recovered to bullion on-site and optimisation of the grinding circuit to reduce the 80% passing size P80 of the primary grind from 160 to 121 micrometres for the same throughput using process control, cyclone and ball charge optimisation. The supporting test work and the plant data before and after the changes are presented., Projects are described that have contributed to improving Au and Cu recovery by 3%-4% at the Cadia Valley operations in New South Wales. These have included the installation of a 355 kW stirred-media detritor to create a regrind circuit, installation of froth crowders on the scavenger circuit, installation of a gravity concentrator as part of the regrind circuit to improve Au recovered to bullion on-site and optimisation of the grinding circuit to reduce the 80% passing size P80 of the primary grind from 160 to 121 micrometres for the same throughput using process control, cyclone and ball charge optimisation. The supporting test work and the plant data before and after the changes are presented.

A flotation concentrate regrinding circuit was commissioned in July 2004 in the high-grade Ridgeway Cu concentrator at Cadia Valley, New South Wales. The test-work, circuit surveys and concentrate properties are described which were used as the design basis for the project. Alternative grinding technologies were evaluated and a sand mill was eventually selected. The economic evaluation and detailed design and construction management issues are discussed and preliminary results presented. Concentrate grade was expected to increase from 26.5% to 31.5% Cu., A flotation concentrate regrinding circuit was commissioned in July 2004 in the high-grade Ridgeway Cu concentrator at Cadia Valley, New South Wales. The test-work, circuit surveys and concentrate properties are described which were used as the design basis for the project. Alternative grinding technologies were evaluated and a sand mill was eventually selected. The economic evaluation and detailed design and construction management issues are discussed and preliminary results presented. Concentrate grade was expected to increase from 26.5% to 31.5% Cu.

Plant upgrades are described that were carried out in the Cadia Hill, New South Wales, circuit in April 2003 to improve concentrate quality and metal recoveries from the flotation circuit. The major changes involved circuit reconfiguration to allow all concentrates to be reground to less than 38 micrometres prior to final cleaning, increasing ball charge in the regrind mill to utilise fully all of the installed power, desliming of the cleaner scavenger concentrate to improve the circuit water balance and the inclusion of a gravity concentrator in the regrind circuit to recover more free gold to bullion. Once the flotation circuit had stabilised, concentrate launder modifications and increased froth crowding on the scavenger flotation cells permitted the introduction of stronger collectors without compromising concentrate quality or circuit stability. After 12 months, the Cu concentrate grade had increased by 2% and metal recoveries by 3% and 7% for Cu and Au, respectively. The project capital outlay has been repaid in less than three months., Plant upgrades are described that were carried out in the Cadia Hill, New South Wales, circuit in April 2003 to improve concentrate quality and metal recoveries from the flotation circuit. The major changes involved circuit reconfiguration to allow all concentrates to be reground to less than 38 micrometres prior to final cleaning, increasing ball charge in the regrind mill to utilise fully all of the installed power, desliming of the cleaner scavenger concentrate to improve the circuit water balance and the inclusion of a gravity concentrator in the regrind circuit to recover more free gold to bullion. Once the flotation circuit had stabilised, concentrate launder modifications and increased froth crowding on the scavenger flotation cells permitted the introduction of stronger collectors without compromising concentrate quality or circuit stability. After 12 months, the Cu concentrate grade had increased by 2% and metal recoveries by 3% and 7% for Cu and Au, respectively. The project capital outlay has been repaid in less than three months.

Details are given of the design and construction considerations and commissioning and ramp-up issues relating to start up of the 4 000 000 t/a Au-Cu concentrator at Cadia Valley, New South Wales. Current resource estimates are around 50 000 000 t with an average grade of 2.4 g/t Au and 0.8% Cu. At current processing rates the project life is expected to exceed ten years. The processing plant comprises a 9.75 m diameter fully autogenous mill, a single 6.7 m diameter ball mill, pebble crushers, gravity Au recovery circuit and flotation plant. Upgrades to the existing infrastructure and manning requirements are discussed as well as the effects on operating costs. The processing plant was expected to deliver 290 000 oz Au and 30 000 tonnes Cu in concentrate in its first full year of operation., Details are given of the design and construction considerations and commissioning and ramp-up issues relating to start up of the 4 000 000 t/a Au-Cu concentrator at Cadia Valley, New South Wales. Current resource estimates are around 50 000 000 t with an average grade of 2.4 g/t Au and 0.8% Cu. At current processing rates the project life is expected to exceed ten years. The processing plant comprises a 9.75 m diameter fully autogenous mill, a single 6.7 m diameter ball mill, pebble crushers, gravity Au recovery circuit and flotation plant. Upgrades to the existing infrastructure and manning requirements are discussed as well as the effects on operating costs. The processing plant was expected to deliver 290 000 oz Au and 30 000 tonnes Cu in concentrate in its first full year of operation.

The JKSimMet simulation package has been used in the design and evolution of the grinding circuit at the Red Dome gold/copper plant in Queensland. The concentrator was commissioned in 1989. Since then, various studies have been carried out on the grinding circuit to optimise the operation for each ore type and to check the agreement between the simulated plant design and measured plant performance. A study was conducted in 1991 to evaluate the benefits of pebble crushing. The objective was to increase throughput while treating hard primary ore. The study showed that the throughput could be increased from 100 to 150 tonnes/h for all ore types. Surveys carried out after installing the recycle pebble crusher in 1992 confirmed the expected increase in throughput, as predicted in the simulation study., The JKSimMet simulation package has been used in the design and evolution of the grinding circuit at the Red Dome gold/copper plant in Queensland. The concentrator was commissioned in 1989. Since then, various studies have been carried out on the grinding circuit to optimise the operation for each ore type and to check the agreement between the simulated plant design and measured plant performance. A study was conducted in 1991 to evaluate the benefits of pebble crushing. The objective was to increase throughput while treating hard primary ore. The study showed that the throughput could be increased from 100 to 150 tonnes/h for all ore types. Surveys carried out after installing the recycle pebble crusher in 1992 confirmed the expected increase in throughput, as predicted in the simulation study.