Strategic planning for ARD remediation

Abstract

The Savage River Mine has operated as an open cut iron ore mine on the northwest coast of Tasmania since the mid 1960's. The impact from ARD became evident during the 1990's when monitoring found high levels of Cu and low pH in the river over 30 km downstream of the mine. Closure of the mine in the mid 1990's and subsequent reopening by new owners resulted in funding of approximately A$24M for remediation to be administered by a joint committee representing the mine owners and the Tasmanian state government. Ecotoxicology work showed that Cu was not acutely toxic to aquatic life forms provided alkalinity levels of more than 15mg/L and pH>6.5 were maintained in the river. A feasibility study established methods of achieving these goals by a range of measures including oxygen exclusion covers, water shedding covers, ARD catch drains, pumping systems and use of centralized treatment facilities. The utilization of naturally occuring magnesite and other alkaline rocks was of particular interest. Capital and operating costs of possible options were estimated to +/- 30% for comparison then a whole of site strategic plan developed to demonstrate how the required level of remediation could be achieved and maintained over a 60-year time span using the funds available. The Strategic Plan showed the committee that the aims of remediation were achievable and delivered a program that could be met by staged development making effective use of the operating mine resources. The paper describes the site, the strategic plan and details of the implementation to date.