Giant Mine Arsenic Trioxide Management Alternative Final Report
Dates
Year
2002
Citation
Steffen Robertson and Kirsten (Canada) Inc,, 2002, Giant Mine Arsenic Trioxide Management Alternative Final Report: Indian and Northern Affairs Canada: Yellowknife, NWT, v. PROJECT 1CI001.10.
Summary
Given that segments of the local community have variously expressed reservations both about options that leave the dust in place and those that bring the dust to surface, the Technical Advisor recommends that at least two alternatives be taken through to public consultation. One of the alternatives carried forward should be the best in situ (“leave underground”) alternative, and one should be the best ex situ (“take it out”) alternative. The Technical Advisor believes that the best in situ alternative is Alternative B3, isolating the arsenic trioxide dust in its current location by creating a frozen block, monitoring in perpetuity, and maintaining isolation by periodic re-freezing. The ground freezing alternatives are generally [...]
Summary
Given that segments of the local community have variously expressed reservations both about options that leave the dust in place and those that bring the dust to surface, the Technical Advisor recommends that at least two alternatives be taken through to public consultation. One of the alternatives carried forward should be the best in situ (“leave underground”) alternative, and one should be the best ex situ (“take it out”) alternative. The Technical Advisor believes that the best in situ alternative is Alternative B3, isolating the arsenic trioxide dust in its current location by creating a frozen block, monitoring in perpetuity, and maintaining isolation by periodic re-freezing. The ground freezing alternatives are generally the lowest risk alternatives, and the frozen block approach has the advantage of being more robust than other variants. The Technical Advisor believes that the best ex situ alternative is Alternative G, dust extraction and encapsulation. The data available to date suggest that using bitumen would better confine the arsenic, thereby resulting in lower long-term risks. However, to our knowledge, bitumen encapsulation has not been applied at this scale. Cement encapsulation, on the other hand, is a well proven technology. The Technical Advisor therefore recommends that DIAND carry forward encapsulation with cement as the preferred ex situ variant, but that the development of full scale bitumen encapsulation be further considered if an ex situ approach is ultimately selected.