Seepage Study (ML15) (Also Called Soil Monitoring – ML15)

During the 2006 monitoring year, Suncor initiated the Seepage Study on ML15 to evaluate whether salinity is increasing on Dyke 11A North as a result of seepage from the tailings pond 8A. The study was designed to determine the amount of salinity present in the upper and lower subsoil. In 2010, the topsoil horizon was included in the study. In 2011, two vegetation transects were established.

The monitoring results obtained over the last 6 years at the ML15 Dyke 11A North site indicates light fluctuations in EC and SAR values in topsoil and subsoil samples collected at the site. Both these parameters do not appear to show any consistent increases over the duration of the monitoring study. In addition, the reported values over the study period are considered to be in an acceptable range for plant growth. Based on these results, it can be surmised that there are no direct effects of salinity at the ML15 site as a result of seepage from the tailings pond and that further monitoring is not warranted.