Hello, dwayne.
The best answer I can give myself is "A long time."
Otto may have the most muck experience of anyone here; he says that muck 18" thick won't ever dry (and that's in Texas). So 12" thick would take a while, I am afraid.
P.S. Otto usually posts incredibly early in the morning. Hopefully he will see this tomorrow or the next day. Not that someone else won't have a much better idea than I do as well.
Last edited by Theo Gallus; 03/26/09 10:08 AM.