Understanding and Assessing Impacts
Rainfall and run-off events in 2008 and 2009 forced the company to ask for amendments to its water license to release untreated water into the Yukon River system. In 2008 heavy rains resulted in flooding and the mine’s water treatment plant was overwhelmed resulting in the release of some 350,000 cubic meters of untreated water into the Yukon River, and the effluent content (.05 mg per litre) was higher than Yukon license standard of .01 mg per litre. Ironically the water storage pond had been designed to assure water availability throughout the year, given an expectation of occasional seasonal summer drought. The 2008 rainfall also washed out a four kilometre section of the mine haul road to Minto Landing, linking into the Klondike Highway. In 2009 the problem of excess water on the mine-site, this time attributed to unusually heavy spring melt, was exacerbated because the wall of as storage pit was partially collapsing because of permafrost melt, and 750000 CM of water were discharged into the Yukon River system.