The Giant Mine cleanup team deployed helicopters to suppress dust as high winds battered Yellowknife this week.
Two helicopters dropped water on dry areas of the former gold mine’s tailings ponds. The mine’s federally led remediation team said air quality monitoring showed no indication of any increased risk to Yellowknife, Dettah, or Ndilǫ.
Dust from the mine site in the air has been a source of concern for residents in the past.
Natalie Plato, the team’s deputy director, said two warnings – known as PM10 warnings for the size of the dust particles – were triggered this week at an air quality station near the northernmost point of the mine site.
“Levels remained under the risk-based action level,” said Plato.
According to Plato, the dust came from two tailings ponds – areas where mine water is stored before being treated.
“The project team has been in communication with rights-holders and stakeholders about the visible dust and measures being taken to address it,” she said.
Plato said her team uses specialist dust control products, wets down the tailings ponds, and stops work that might contribute to dust release on windy days.
In the past, the remediation team has said “very little” toxic arsenic trioxide material is contained in the dust.
There are 227,000 tonnes of arsenic trioxide buried beneath the mine – the result of the roasting technique used to extract gold while the mine was operational.