11/10/2012 - saw a reference to this falls on the net, so I set out to find it. Turned out to be easy. The entrance to the old mill is at the Ruffs Mill-Concord Covered Bridge, near Smyrna, GA. The falls is small, and down a steep creek bank. It looks like it is possible to get closer to it, but since I got there late and was alone, I decided to just get the best picture I could from above.
According to GMAPS this falls is on Nickajack Creek