Fuel contamination characterization in permafrost fractured bedrock at the Colomac mine site

A study is being conducted into the behavior of fuel contamination in permafrost fractured bedrock at the abandoned Colomac gold mine site, approximately 220 km north of Yellowknife. The site has 0.2–4.6 m of overburden over fractured bedrock, and is adjacent to Steeves Lake. Free-phase hydrocarbons have been observed atop the water table in many of the 33 monitoring wells installed at the site. Detailed sampling, hydraulic testing, subsurface water and thermal regime monitoring were conducted from June 2005 to 2006. Hydraulic tests showed that portions of the bedrock are fractured and permeable, and the water chemistry suggests active anaerobic biodegradation. The study is still ongoing to properly characterize the complex groundwater and thermal regime.