Mining Magazine > Panorama > Outotec TankCell success at Macraes

Panorama

Flotation major Outotec has announced the successful ongoing performance of its TankCell-300 flotation cell train at New Zealand’s largest gold producing operation, OceanaGold’s Macraes mine.

Since the installation of three Outotec TankCell flotation cells in a single train, gold bearing sulphide recoveries have been boosted by 3%, and an extra 6Mt/y throughput of ore has been achieved. The cells also provide better mechanical and metallurgical stability, and require less maintenance than the previous two-train circuit used by the mine. In total, production at Macraes has increased 42% to 259,812oz in 2008.

The solution proposed by Outotec, and detailed by Mining Magazine in its November 2008 flotation focus article ‘Bigger really is better,’ was commissioned in November 2007. The order included three TankCell-300 flotation cells, each with over 300m3 active flotation capacity, plus Outotec’s FrothMaster 2 froth imaging system and ACT Control System.
 
Peter Bourke, principal metallurgist for Outotec’s global flotation division explained: “The introduction of the new TankCell-300 scavenger cells achieved all of the project aims. The new circuit at Macraes was projected to improve gold bearing sulphide recovery by 2.5%, and economical evaluation based on that yielded a payback time of about 16 months. According to average metallurgical results, the bulk flotation recovery has improved by 3%. This successful commission represents a groundbreaking worldwide development for flotation technology.”

Further analysis on the performance of the new TankCells is planned, including full size-by-size metallurgical surveys and ongoing analysis of operating costs. The information will be used for further development of new TankCell designs and to optimise existing cells.

In addition, Outotec has also recently finished testing a TankCell-300 flotation cell at Codelco’s Chuquicamata copper mine in Chile. The cell was tested against the plants existing TankCell 160 circuit installed by Outotec in 2001.

In its initial setup, the single TankCell-300 was measured to be 3.7% units higher on recovery compared to the two TankCell-160 machines in the parallel bank, while reaching equal grade of copper in concentrate averaging 20%. An alternative hydrodynamic setup of the TankCell-300 was also trialled. The cells were fed with lower-grade ore containing 0.49% copper, which improved the metallurgical results further, with over 5% units higher recovery and 1% unit better concentrate grade than in the parallel two TankCell-160 cells.

During the entire testing program, the TankCell-300 did not exhibit sanding or mechanical problems and has subsequently been incorporated into flotation circuit of Division Codelco Norte.