|Title||Arsenic speciation in mine tailings and co-existing pore water, Lower Seal Harbour Gold District, Nova Scotia, Canada|
|Author||Daniels, C; Parsons, M; Jamieson, H; Hall, G|
|Source||Proceedings of the 9th International Conference on Acid Rock Drainage; 2012 p. 1-12|
|Alt Series||Earth Sciences Sector, Contribution Series 20110327|
|Meeting||9th International Conference on Acid Rock Drainage; Ottawa; CA; May 20 - 26, 2012|
|Area||Lower Seal Harbour|
|Lat/Long WENS||-62.0000 -61.5000 45.2500 45.0000|
|Subjects||environmental geology; geochemistry; mining; gold; mining activities; tailings; tailings analyses; tailings geochemistry; arsenic; arsenic geochemistry; arsenopyrite; pore fluids; pore geometry; pore
water samples; environmental impacts; environmental studies; mine waste products; health hazards; Paleozoic; Ordovician; Cambrian|
|Illustrations||location maps; plots; micrographs|
|Program||Program management and Transition Activities, Environmental Geoscience|
|Abstract||Environmental impacts from historical mining and milling of lode gold deposits in Nova Scotia include elevated arsenic (As) concentrations within the tailings and in downstream receiving environments.
The Lower Seal Harbour Gold District (LSH) operated from 1904 to the mid-1940s and produced approximately 395,000 tonnes of tailings. This study examined As speciation in tailings and associated pore waters to better understand the processes that
control the mobility of As from these mine wastes.|
Within LSH, three geographically and geochemically distinct sample locations were chosen to collect tailings and pore waters, including (1) sub-aerially exposed tailings; (2) shallowly submerged
tailings; and, (3) tailings that are present in the intertidal zone of Seal Harbour, 2 km downstream of the milling operations at LSH.
Arsenic is present in the tailings at Sites 1, 2 and 3 at maximum concentrations of 9,200, 12,000 and 1,040
mg/kg, respectively. Elevated concentrations of As corresponded to arsenopyrite-bearing sections of the tailings cores, or intervals with abundant As-bearing secondary phases. Pore water analyses indicate high concentrations of As and pH values from
6.2 to 8.0.
Results from this study have helped to clarify the environmental risks associated with these historical mine wastes, and will support better informed land-management decisions.