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Abstract |
Previous mining history in Norway has resulted in ongoing release of acid mine drainage. Preservation of the historical sites in mining areas does not allow for remediation technologies that result in significant alteration of the historical landscape. Therefore, alternative remediation techniques such as passive mine water treatment have been tested. The climate in Norway varies from mild coastal climates to artic climates, and one of the challenges with passive treatment systems is the cold winter conditions. Anaerobic treatment systems have been built at Kongens Mine near Røros, at Folldal mines, and at Titania's tailings impoundment near Storgangen Mine. These systems utilize sulfate-reducing bacteria that result in the precipitation of metal sulfides. A full- and pilot-scale system at Kongens Mine and Folldal were built in 2006 to remove copper and zinc from typical ARD in an alpine climate. Previous testing with pilot scale systems at Kongens Mine showed that up to 85% copper and 48% zinc could be removed. At Titania A/S the anaerobic system is designed to remove nickel from neutral waters. At this system over 90% nickel is removed when water flow is regulated at a constant flow. Testing shows that the system can function in cold winter conditions, however, optimal metal removal is achieved under warmer temperatures. Temperatures changes by global climatic warming will not adversely affect these anaerobic systems. However, extreme precipitation events and the resulting rapid fluctuations of ARD runoff will provide a challenge for the effectiveness of these systems. |
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