Jim...
If you have access to Yahoo maps, type in Petersburg, Virginia and move the map to the west side of town. It shows a little strip of land west of the railroad bridge to Ettrick between the Appomattox River and the Appomattox Canal- that's probably the site. It appears to be just to the west of where Lee had his headquarters. The camp would have been quite a ways from the Crater. Fulton mentioned that they had been stationed close to where the explosion occured- do you have any more information on that?
I believe that Sander's Brigade were the only Alabama troops involved in the attack on the Crater.
John