Macquarie University
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Diagnosis of a base metal mine tailings capping failure

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posted on 2022-03-28, 18:20 authored by Gyan Connor
Conrad, in northern NSW, is a derelict base metal mine that has undergone extensive rehabilitation. In 2002, the upper tailings (UT) was hydraulically isolated through clay capping; however this was unsuccessful as As, Pb, Cu, and Zn enriched water is exiting the containment structure into Borah and Maids creeks, then Copeton Reservoir, the local drinking water supply, 3 km downstream of the mine. This thesis identifies UT as the highest priority for further rehabilitation. The UT is characterised through elemental and mineralogical analysis of solid samples taken from 0-10 m depth, and leachate extraction from tailings. Metal(loid) concentrations of sediment and water exceed NEPM and ANZECC guidelines onsite and downstream of the mine. Aquatic macroinvertebrate edge sampling along the creeks shows decreased family richness and diversity onsite and downstream from the mine. These results show that capping of the UT has been ineffective, and improvements are suggested to properly rehabilitate the area to stop further offsite spread of contamination. These include a replacement capping design incorporating geofabric, and investigating the possibility that water is infiltrating through the fractured granite in the valley wall on which the UT rests.


Table of Contents

1. Introduction -- 2. Regional setting -- 3. Current site condition -- 4. Methods -- 5. Results -- 6. Discussion -- 7. Recommendations -- 8. Conclusions -- 9. References -- Appendices.


Bibliography: pages 51-53 Empirical thesis.

Awarding Institution

Macquarie University

Degree Type

Thesis MRes


MRes, Macquarie University, Faculty of Science and Engineering, Department of Environmental Sciences

Department, Centre or School

Department of Environmental Sciences

Year of Award


Principal Supervisor

Damien B. Gore

Additional Supervisor 1

Scott Wilson


Copyright Gyan Connor 2018. Copyright disclaimer:




New South Wales


1 online resource (v, 61 pages) colour illustrations, colour maps

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