Got it, thanks.
I was interested because there is a chemical plant here that had contaminated the surrounding area and they were looking into similar technologies to prevent the contaminants from further leaching out and affecting the groundwater and the surrounding neighborhood. They were looking at a curtain some 200 feet deep, surrounding the plant, which is roughly a mile square in area.
To All, bentonite can be considered, for non-engineering purposes, to be "clay", which may help in understanding the technology under discussion.
Yeah, simply put it's a Wyoming sodium montmorillonite clay. Well, the good brands, anyway.
For applications 200 feet deep, a backhoe will not work. IIRC, the deepest digging backhoe is owned by RECON from Houston. GEOCON is another excellent slurry trench contractor.To go 200', an clamshell on a crane will be needed. In this case, I think TREVIICOS is the company to go to.
ICOS, predecessor to TREVIICOS did the first structural slurry walls in America at the World TRade Center. I had the opportunity to work with several people who were involved with that project (All old guys from Italy).