Civil Engineering grade bentonite has for many years been used in diaphragm walls construction, tunneling and dam sealing.
VOLCLAY CE grade is available in 1 tonne bulker bags and 20 tonne tankers as we as the standard 25kg bag. Given the ability of bentonite to swell up to 15 times its original bulk, it is ideally suited to blend with a soil layer and be compacted in the base of a during dam during construction.
VOLCLAY bentonite is inert except for a light alkalinity, is harmless to the human digestive system and can be dried & re-swelled an infinite number of times.
VOLCLAY SP (powder) and VOLCLAY SG (granular) are prepared especially for dam sealing applications and are available from long (Vic) and Miles (Qld).
Further Reading:
Puncture the bottom of a container with a number of holes to make a sieve and cover the bottom with 25mm of gravel or coarse sand. Water will flow through freely . Now cover the sand or gravel with 10mm of Volclay SG and put a layer of sand over it.
Fill with water. It will not penetrate!