| yikes! what kind of stone? square edge builders or round boulders? sounds like you only mortared the backing to give the appearance of a dry stack? If so you may be able to salvage most of it by using the same faces of the stones for your rebuild. If not you may be in tough to rebuild without exposing any mortar stains. From my experience the chalk grid doesn't work. you get off by a quarter inch with one stone and down the line your whole grid doesn't line up. Thats assuming your even able to keep track of every stones place in the grid, lose track of one stones original placement and good luck lining up the rest. That was with a flagstone pick up and relay mind you, I have never tried on a wall but if your using round basket ball sized stones, good luck. Section off your wall into 5 foot spans. Number each stone with chalk and take a few photos of each section (with the chalk you have to work quick enough, take a few days get some rain and all your chalk markings are gone!). When you deconstruct pile the stone together by section. Taking photos before is key and try to identify a couple benchmark stones or corners and their exact placement and work toward lining them up. When you rebuild constantly refer to the photos. Deconstruct with a pneumatic chisel, not a hammer drill. Remove the concrete pad if you can. Rebuilding a gravel base on top of concrete is never a good idea. Good luck. | 
