 |
|
|
|
|
   
|
Lake data monitored Spindle-legged lakeside sampling station
gathers information for tailings pond
constructionJack Danylchuk Northern News Services Published Wednesday, August 3, 2011
The water teems with bugs and thin red worms that don't seem to mind its high arsenic load: 1.62 parts per million, or approximately three times the metal mining effluent regulations limit of 0.5. But those unremarkable features make the lake - tucked away in the granite folds above Giant Mine - perfect for Bob Reid's purpose: designing and building better mine tailings ponds. Before 1993, mining companies used data gathered from an evaporation pan - used to hold water and determine the quantity of evaporation at a given location - at Yellowknife Airport to gather the information they needed to design tailings ponds, said Reid, a hydrologist with the water resources division at Aboriginal Affairs and Northern Development Canada. "Everyone knew it was wrong," said Reid, but there was no other data until he installed a lakeside monitoring station in 1993. Bristling with sensors, the spindle-legged station samples air and water temperatures, relative humidity, wind speed and direction, rainfall, water levels and net solar radiation. Analysis revealed that the lake loses between 400 and 427 millimetres of water a year, compared to the 470 mm that disappears from the airport evaporation pan. "The difference is not that critical in Yellowknife," said Reid, but at more distant mine sites like Tundra, Ekati or Nanisivik, where the variance from the airport is more than 200 mm, the difference could cause problems after a mine closes and there is no one on site to manage the situation. "We've demonstrated that just $10,000 worth of equipment can eliminate guesswork." Reid has battled "tooth and nail" through budget cuts to keep the station near Giant Mine running. Monitoring costs about $500 a year and will continue, at least until Reid retires in five years - and beyond, he hopes.
|
