Figure 9 – Reduction of airflow rates in upgraded cells at Kennecott Copperton. Moreover, based on the measurements taken from Red Chris mine, the air flow rate of the cells was reduced by around 25 per cent with similar froth bed thicknesses, improving the overall flotation bank performance (Seaman et al. 2021). This reduction in operative airflow rates was achieved because of smaller froth transport distance, and therefore increased crowding. As a result of center launder upgrade, the Red Chris mine was able to increase the operating range of the cells, therefore improving the mass pull rate sensitivity for operational changes and maximizing the recovery of coarser particles. Similarly, the operating air flow rates at the New Afton Concentrator were reduced by an average of 22%. In this case, the last two of the six flotation cells in the operating rougher line were upgraded with center launders. Following the retrofit, the operational range of the cells increased significantly, enhancing the overall stability of the process. Additionally, the substantial 68% decrease in froth surface area enabled increased crowding, resulting in higher superficial gas velocities without any disturbance in froth zone. (Metso 2021) This reduction of the airflow rate is expected to reduce the power consumption of the blower, thereby reducing the energy costs (Bermudez et al. 2022). In addition to the decreased operating airflow rates, the froth bed thickness increased following the completion of the center launder retrofit installation. Earlier research indicates that a deeper froth bed helps to restrain the recovery of valuable minerals by allowing undesirable material to drain back to the collection zone (Wang et al. 2020). It has been also measured that the thicker froth bed increases the froth stability, therefore improving the gained overall recovery (Farrokhpay 2011). Accomplished measurements at Kennecott Copperton showed that the froth bed thickness increased by an average of 22%, 35%, and 22% for the three upgraded cells, respectively. (Bermudez et al. 2022) These results are illustrated in Fig. 10.
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