scsims, sir I don't know as much as any of these guys, but I have seen ag lime and spread some too and I don't think it would expand much to plug anything.
I did find where there are some Barite mines in KY. The haul bill on bentonite would cost more than the bentonite alone, but if the Barite is similiarly priced and is better, well the haul bill would be a whole lot less for you than bentonite. Check out google and type in "Barite Kentucky".
