Passive Metalliferous Mine Water Treatment with Recycled Concrete Aggregate

Vollständiger Abstract

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Abstract Metal-impacted water is generated by most metal mine facilities, usually in perpetuity. Responsible and legal mining requires that this water, when discharged, must meet water quality standards that protect human health and the environment. However, active treatment at most mine sites is difficult and expensive to maintain, particularly after the cessation of operations. The project described in this paper has demonstrated a successful method of long-term passive treatment of metalliferous mine water using universally available recycled concrete aggregate as the treatment medium. The method is to pass the metalliferous water upward through a large bed of recycled concrete aggregate with particle size between 10 and 40 mm, retain the water in the bed for between 4 to 8 days, and discharge the treated water into a surface pond above the recycled concrete aggregate bed. Engineering design instructions are provided for the passive treatment facility. This design provides long-term removal of deleterious and potentially toxic metals from the mine water, particulate filtration to retain the removed metals in the treatment system at non-hazardous levels, and oxidation and polishing before final discharge. The 14 long-term tests presented in this paper demonstrate that there is always a retention time that achieves the desired long-term treatment of metals when the passive treatment facility conforms to this design specification.