Base de données de recherche des TNO

Régions: North Slave Region

étiquettes: water quality, aquatic ecosystems, environmental monitoring, mining impacts, phytoplankton, water sampling, zooplankton, aquatic environment, diamond mining, kimberlite, tailings disposal

Objectif(s): In the Fall of 1998, BHP's Ekati Diamond Mine, the first diamond mine in the NWT, began mining operations. Presently, this mine processes approximately 9000 tonnes of kimberlite per day. Manual crushing is used to reduce the ore, which is then washed and separated based on size. Particles of 0.5 mm to 8.0 mm eventually end up in a coarse tailings collection site, while the kimberlite fines (<0.5 mm) are pumped, along with the water used in the extraction process, to Long Lake. As part of its Type "A" Water Licence (# N2L2-1616), BHP was granted permission to sacrifice Long Lake for fine tailings containment purposes. Long Lake therefore offers a unique opportunity to study the sequence of ecosystem changes that result from the addition of processed kimberlite to an aquatic environment. The field component of this study involves collecting zooplankton, phytoplankton and water samples to determine the impact that the fine kimberlite tailings effluent has on Long Lake. This study of the changes within Long Lake is highly relevant to our understanding of kimberlite toxicity and to the appropriate management of processed kimberlite. Information developed will allow the diamond mining industry to minimize adverse effects on the environment, which is an important component of the long-term sustainability of this industry in the NWT.

Description du projet: The research team will be transported to Long Lake by aircraft, and will travel by truck on the mine site. Sample collection will be carried out using a motorized boat. Water and phytoplankton samples will be collected using a 10 L Go-Flo water sampler. Zooplankton samples will be collected using a zooplankton net. There are three taxa of freshwater zooplankton that may be collected from Long Lake: rotifers, cladocerans and copepods. There are five designated sites on Long Lake, which will be sampled at two depths: 1 meter from the surface and 1 metre from the bottom of the lake. Field work will be conducted by the primary researcher assisted by BHP environmental staff . No field camps will be used, all garbage will be packed out, and all human waste buried.