Slowly heading for the exit to the car-park I dug the occasional target that turned out to be nothing more than WWII scrap. Investigating an area that looked as though an other detectorist had been digging, I then stepped firmly on the sand to move on and to my surprise there was a dull report beneath the sand and it fealt as though the sand was going to drop into a cavity beneath my foot. It sounded like a muffled shotgun report, or a rapid roof fall in a mine. "Thump!" I know it wasn't a land-mine; I still have all my toes, but I got to wondering if could be old mine shafts collapsing in the area.
Anyone ever come across the like?
