Sealing Boreholes in Rock Salt

Effective sealing of penetrations (boreholes) in geological materials is becoming increasingly important as it is recognized that groundwater resources need to be protected from potential contamination. In the undisturbed geological system, potential contaminants are separated from freshwater aquifers by low-permeability aquitards including evaporite deposits such as bedded and domal halites. Improper plugging, sealing or abandonment of boreholes which penetrate aquitards can allow the bore- hole to act as a conduit between the contaminated and freshwater regions. Borehole seal performance has been recognized as a potential environmental concern by numerous researchers (e.g. USEPA, 1977, 1987; Freeze and Cherry, 1979; National Research Council, 1985; Smith and Browning; 1993; Smith et al., 1993).