NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: biology, mining impacts, fish health, cumulative effects

Objective(s): This study will assess the effects of blasting activity at the Diavik Diamond Mines Inc. Lac de Gras mine site associated with proposed mining activities that would use explosives as the primary method of excavating rock. The resulting explosions will produce peak particle velocities and over-pressures that radiate outward from the A154 pit, likely extending beyond the pit's dike walls and into Lac de Gras, where they could cause death or injury to fish. Consequently, a Fisheries Authorization (SC98001) relating to this activity requires that peak particle velocities and overpressures resulting from blasting activities in and around the predicted blast zone be monitored, to define the actual blast zone. Effects of blasting on fish must also be determined. In particular, any incubating fish eggs within the blast zone could be susceptible to mortality or damage, especially since they would be exposed to the excessive velocities or pressures for 6-10 months. Since there is considerable uncertainty regarding the cumulative effects of repeated blasting on overwintering, developing eggs in Arctic lakes, and because the use of explosives in or near arctic Canadian fisheries waters will likely increase in the future, the results of this study will be important both with respect to the A154 pit but also to assess more generally the relationship between current guidelines and effects under arctic conditions.