Colloid and particulate matter studies in the Cigar Lake natural-analog program

The Cigar Lake uranium deposit in Northern Saskatchewan is being studied as a natural analog to a used-fuel disposal vault. This paper describes groundwater colloid and particulate matter studies at Cigar Lake, carried out to support the analog program and to obtain basic information about colloid properties and their migration behavior in a natural environment. The concentration of natural groundwater particles (0.6 to 261 mg/l) was found to depend on groundwater chemistry and the amount of local fracturing and alteration of the rock formation. The presence of U, Th and Ra-226 in particulate form is a function of total particle concentration and composition. No significant colloid migration has been observed from the ore deposit to the surrounding sandstone. (orig.)