This study compares select dust sampling apparatuses and monitoring methods by investigating fugitive tailings dust transport and deposition at an abandoned Zn-Pb-Cu mine located in eastern, Canada. The sampling apparatuses and monitoring methods are compared in terms of capturing seasonal trends and spatial extent, as well as the ability to evaluate impacts to aquatic ecosystems. Methods evaluated include satellite imagery, lichen tissue analysis, passive dry deposition collectors (Pas-DDs) with two different configurations, dust deposition gauges (DDGs) and a high volume total suspended particulate (Hi-Vol TSP) sampler. All methods utilized demonstrated benefits and challenges in relation to seasonal sampling and determining spatial extent of dust deposition. Results indicate that the polyurethane foam disk configuration of the Pas-DD sampler efficiently accumulates dust in comparison to the glass fiber filter configuration and DDGs which both likely underestimate dust deposition. Lichen and satellite imagery were shown to be effective tools for identifying areas of interest and extent of contamination. At the study site, it was observed that dust deposition was highest in the winter months and lowest in the summer months, likely due to increased erosion in winter weather conditions (higher wind speeds and/or freeze drying effect).
The increased potential for dust mobilization as a result of climate change indicates a need to better understand interactions between dust and water. This research investigates the geochemical effects of tailings dust on surface waters near Stirling mine, Nova Scotia. Tailings were sieved to <63 mu m as a proxy for dust and analyzed geochemically and mineralogically for the identification of primary and secondary metal-bearing phases using a scanning electron microscope with automated mineralogy, electron microprobe analysis and synchrotron-based microanalysis. Metal-hosting phases identified include in order of abundance; sphalerite (ZnS), cerussite (PbCO3), chalcopyrite (CuFeS2), Pb-Mn phases (possibly ces`arolite (PbMn3O6(OH)(2))), smithsonite (ZnCO3), goethite (FeO(OH), aurichalcite ((Zn,Cu)(5)(CO3)(2)(OH)(6)), hydrohetaerolite (ZnMn2O4 center dot H2O), tennantite (Cu-6(Cu4Zn2)As4S12S), and galena (PbS). Shake flask tests were conducted in simulated stream waters (pH = 7) using sieved tailings and passive dry deposition collector filters to investigate the solubility of metal-hosting mineral phases within dust. Results indicate metal leaching at near neutral pH conditions. Sphalerite, cerussite and chalcopyrite are likely the main sources of Zn, Pb, and Cu in the shake flask leachate, based on calculated saturated indices and mass balance. Analyses of stream waters indicate similar conditions (pH, ORP, saturation indices, etc.) compared to the results of the shake flask tests, suggesting they provide reasonable insight about processes occurring in the field. Tailings dust generated at the site is therefore a potential source of metals to surface waters.