Dust in the wind
Giant Mine's air monitoring systems register higher than normal levels of contaminants in recent weeks
Cody Punter
Northern News Services
Published Friday, May 16, 2014
SOMBA K'E/YELLOWKNIFE
Winds carrying dust from Giant Mine have caused air monitoring stations across the city to register levels of "particulate matter" that exceed the federal government clean-up crew's minimum thresholds in recent weeks.
Air monitoring stations at Giant Mine have registered higher than normal levels of contaminants in recent weeks due to dust carried by wind. The average levels registered on May 2 were nearly six times higher than the allowed limit. - NNSL file photo |
According to several reports released by Aboriginal Affairs and Northern Development Canada (AANDC), levels of particulate matter were higher than Ontario Ambient Air Quality standards - which are used as the standard for the mine's cleanup - on several days between April 26 and May 2.
The most recent incident occurred on May 2 when monitors located on the fence-line of the Giant Mine site registered 15-minute average dust particle levels that were more than five times higher than the thresholds set for area.
The average levels for the day was 923.9 micrograms per cubic metre, while the limit for the monitors at the mine site is 159 micrograms per cubic metre.
The report for that day states the high levels of dust were "caused by soil erosion from the south tailings pond area associated with strong winds from the north-northwest."
The project team responded by watering the tailings areas "to prevent further fugitive dust emissions."
The next day, the average was back down to 5.8 micrograms.
Three other incidents were recorded on April 26 and 27 and May 1, at the project's three community monitoring stations, located at the Yellowknife Cruising Club, in Ndilo and the downtown core.
The reports state that those stations registered 24 averages of airborne contaminants that were a few micrograms higher than the recommended maximum of 50 micrograms per metre for the monitors in the city.
The reports state that the project team was unable to say where the dust came from but attributed its spread to moderate winds.
The purpose of the city's air monitoring systems is to ensure residents are not exposed to unacceptable levels of contaminants as a result of cleanup efforts at Giant Mine.
According to an e-mail from an AANDC representative who asked not to be named, the dust registered by the monitor can consist of anything from "pollen, road dust and smoke," among other things.
