Hi Downdeep, yes I have dug up around 2 old stamping batteries and if they haven't been really well cleaned up they can be very good producers. If you can flood the area around the foundations and dredge it that would probably be the easiest way to go. I used a highbanker set up to do one and the other one I used a pump and motor to sluice it all down a ditch I dug and lined with rough riffles.
The old time miners were quite sloppy with their amalgam, and spilled a little often - this can add up to a whole lot around the old foundations - get as deep around them as you can, right to rock bottom if possible, and if they are wooden like the foundations I dug - the amalgam gets right into the wood as it cracks open, and even more at the joins.
As well as the stamper foundations there will be an area nearby, with a lot of old ashes and metal junk associated with it. This is where they retorted and melted their amalgam and gold. This would have also had a lot of gold around it. Splatters and balls of gold, from the melting, dropped amalgam, glassy looking melted borax with gold in it, and broken or even whole ceramic crucibles with even more gold stuck to them. Some of this stuff will have to be broken up and crushed fine in a dolly pot. Probably a good way to go would be to sieve all this stuff - put the fines through a small box and visually inspect the rest for signs of gold.
Good luck with the clean up, wish I was closer to help

. If it has not been done well you should be able to find quite a few ounces, provided it was worked for a reasonable number of years. Nuggy