• Why use foam? • PUF for geo-technical applications
You may ask “why foam instead of concrete or backfill.” Simply, foam is more cost effective and will outlast even dirt! Foam weighs 1/50th as much as concrete or dirt and is basically impermeable to water, which means it is also very immune to erosion. (Compare foam to concrete)
If you backfill a shaft or a void, surface water will continue to compact, erode and transport the fill material into the mine or karst feature, sometimes for years. Pumping action on the hole or shaft will constantly increase the area and may re-expose an adit, portal or cave. Also, with foam, you don’t fill the entire feature, rather you plug the top of a shaft or outby end of an adit. Typically any shaft more than 100’ deep is cheaper to foam than to fill. Now add in constraints such as habitat in and around waste piles, the Acid Rock Drainage (ARD) nature of waste and the potential archeaologic nature of the mine site, and PUF beats fill by a bunch! (Plug Thickness Calculator)
Compared to concrete, foam will not shrink or fail under its own weight. Low shrinkage means less erosion and piping around and under concrete caps. The light weight translates to less surface disturbance and greatly reduced transportation and installation costs.
Foam can even outperform grout and bentonite because of its lightweight nature and solidified state immune to changes in moisture content. Once in place it stays in place! (Oh, and it sticks to everything!)
-Ed Winchester, Frontier Enviro[...] (full)
4255 S. Eagleson Rd
Boise, ID 83705
Phone: 800.556.9641
Fax: 877.327.1196