Stability of natural barriers exposed to uranium mill wastes

Till, silt, clay, peat and soils modified with commercial bentonite can be considered for use as barriers to seepage from uranium mill wastes impoundments. Hydrogeochemical processes including dissolution, reactions, replacement reactions, precipitation reactions and ion exchange may alter the physical characteristics of the barrier materials. Similarly, the permeability of the barrier may be altered due to physical changes such as swelling, development of cracks or fissures, or piping. This paper explores how physical and geochemical processes may affect the performance of natural soil barriers