NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: contaminants, arsenic, tailings disposal

Objective(s): To analyze near-surface tailings from the tailings ponds and shoreline at Giant Mine in Yellowknife, Northwest Territories, and to distinguish the arsenic-hosting phases in both the bulk tailings and the fine fraction of the tailings from the site.

Project Description: The primary objective of this research is to analyze near-surface tailings from the tailings ponds and shoreline at Giant Mine in Yellowknife, Northwest Territories, and to distinguish the arsenic-hosting phases in both the bulk tailings and the fine fraction of the tailings from the site. The research team will initially take near-surface samples of tailings - from which windblown dust may be sourced - from the site’s tailings ponds and the shoreline where runoff from the ponds was able to enter Great Slave Lake. Sampling sites will comprise locations within the ponds where tailings have a history of accumulating. Previous studies of Giant Mine tailings have shown that the most effective method of analyzing arsenic-bearing particle samples is with synchrotron microanalysis. This method is ideal for characterizing material of small particle size and amorphous structure; therefore, it is ideal for characterizing metal-bearing particles. Using these methods it is possible to distinguish two oxidation states of arsenic present within the tailings. Due to its bioaccessibility, arsenic trioxide is the arsenic species that poses the greatest health risk. The research team will first characterize the mineralogy of the tailings from each of the sample sites, so as to gain a detailed picture of the composition of the surface tailings and the arsenic-hosting phases present. The team will then set up filters at the tailings ponds to collect airborne particulate matter, and apply the mineralogical characterization to the dust samples to determine if arsenic-hosting phases are present within the dust as well. Throughout the course of this project the research team will work directly with Yellowknife community members whenever possible. The team will be in direct communication with the Yellowknife Dene First Nations community, as they reside immediately downwind of Giant Mine. They could provide useful insight into the concerns regarding dust-carrying windstorms, and can further educate the research team on the impacts of the mine. Research findings will be available to all interested community members in Yellowknife. As this research pertains to the arsenic content of dust from Giant Mine tailings, the findings will be particularly useful to long-term Yellowknife residents who are at risk of dust inhalation on a daily basis. Through the course of field work the research team will participate in community activities whenever possible. Once research has been completed, the results will be communicated to local Yellowknife community members through a combination of conference and community presentations, and written results being made publicly available. Specifically, the Principal Investigator will present the findings at the annual Yellowknife Geoscience Forum in 2016, and to the Yellowknife Dene First Nations community. The fieldwork for this study will be conducted from May 1, 2016 to May 22, 2016.