The evaporation project commenced earlier this year, after Queensland Nickel had exhausted all the possible options for the disposal of excess site water that resulted from Townsville’s 2007 and 2008 heavy wet seasons in the area.

The company needed to source a solution to manage the disposal of the water in an environmentally friendly and efficient manner, and sought the assistance of Resource Equipment Rentals (RER).

The solution put forward by RER was ‘assisted evaporation’.

While the concept of evaporation of large bodies of water is not new, RER offered to accelerate the process to the point where evaporation becomes a viable option, as opposed to the alternatives of pumping or disposing of the water.

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The assisted evaporation process

The assisted evaporation process was achieved by discharging the water via custom designed and built cannons or monitors. With the assistance of a high velocity turbine, the water is discharged directly into a column of air through a specially designed injector bar and nozzles to achieve a minimum particle size. This particle is then ejected at high speed to a certain height and, if conditions are favourable, the monitors can evaporate between 60–100 per cent of the product put through the system.

The system included full telemetry operation with fully automated self-monitored condition controls.

The system was controlled by custom built and designed weather stations, which RER installed at the site. This meant that the system would automatically start to take advantage of optimal evaporation conditions and alternately, when conditions were unfavourable, shutdown and remain on standby.

Queensland Nickel’s system in tropical north Queensland regularly achieved evaporation rates in excess of 60 per cent, equating to volumes in excess of 10 ML/d.