Excellence in Environmental Management Finalist: Rio Tinto

In an attempt to reduce the amount of unnecessary water waste, Northparkes copper mine joined with Nylex to produce a product that would efficiently reduce water evaporation from large open water storage facilities.

In an attempt to reduce the amount of unnecessary water waste, Northparkes copper mine joined with Nylex to produce a product that would efficiently reduce water evaporation from large open water storage facilities.

The Nylex Aquacap can reduce both solar and wind evaporation while allowing rain water to enter the water storage, maintain water quality and be easy to assemble and transport.

The product is a 1,150 mm diameter, circular, modular disc made of non-toxic, injection moulded, white polypropylene that floats semi-submerged on the surface of the water.

The surface of each disc is solar reflective and curved to reduce both solar and wind evaporation.

When fully deployed, the circular discs cover up to 80% of the water’s surface, allowing sufficient natural light to penetrate and minimise ecological disruption, prevent the build up of hazardous gases and maintain water quality.

Trials were carried out at Rio Tinto’s Northparkes Mine, 25 km north of Parkes, NSW.

Average rainfall for the area was 584 mm with an annual evaporation of 1570 mm.

During the trials, the products were deployed over two purpose built storages, each with a surface area of approximately 0.63 ha.

During the trial, the covered storage lost 210 mm in evaporation and the control storage lost 1,445 mm – resulting in a saving of 1,235 mm or an 85% reduction in evaporation losses. A maximum reduction of 95% was achieved during the winter months.

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