Comprehensive design and implementation of water release of mine waste water with acceptable community response.

It was proposed to use water release to dispose of excess waste water in the tailings dam, accumulated through high rainfall in the summer of 1999 at the Gympie Eldorado gold mine, Queensland. The steps involved in designing and undertaking environmentally safe water release as a model for application under the revised ANZECC (Australia New Zealand Environment and Conservation Council) 2000 water quality guidelines are described. Water analysis showed that antimony and nitrate were the likely limiting constituents for waste water release. A dilution of 1:20 was proposed, when diluted, total and WAD cyanide and arsenic are at safe levels. This dilution was shown to be safe for aquatic biota in tests using Daphnia carinata and Paratya australiensis. It was recommended that the tailings water be diluted with dewatered mine water on site and that contaminants in the mixing zone and aquatic biota in the river be monitored. Monitoring included bioassay in-stream validation. The local community were kept informed throughout the process.
It was proposed to use water release to dispose of excess waste water in the tailings dam, accumulated through high rainfall in the summer of 1999 at the Gympie Eldorado gold mine, Queensland. The steps involved in designing and undertaking environmentally safe water release as a model for application under the revised ANZECC (Australia New Zealand Environment and Conservation Council) 2000 water quality guidelines are described. Water analysis showed that antimony and nitrate were the likely limiting constituents for waste water release. A dilution of 1:20 was proposed, when diluted, total and WAD cyanide and arsenic are at safe levels. This dilution was shown to be safe for aquatic biota in tests using Daphnia carinata and Paratya australiensis. It was recommended that the tailings water be diluted with dewatered mine water on site and that contaminants in the mixing zone and aquatic biota in the river be monitored. Monitoring included bioassay in-stream validation. The local community were kept informed throughout the process.