Estimation of actual LNAPL thickness at a fuel-contaminated Arctic mine site

The estimation of recoverable mobile free product or light non-aqueous phase liquid (LNAPL) is important in monitoring and selecting appropriate remedial techniques. This study used a field empirical approach to estimate the actual product thickness at the Colomac mine site in the Northwest Territories (NWT), which has extensive fuel contamination. The empirical approaches used are described by Hughes et al. (1988) and the modified Gruszczenski method. Of the two, only the latter provided useful estimates of actual LNAPL thickness in the tank farm area where most of the contamination occurred. The estimated LNAPL thickness at the site is 8 cm. Later excavation at the site corroborated this estimated value.