Somebody here trialed a nifty machine a decade or so back. Stones are picked by hand out of potato harvester belts and usually tossed back overboard. This means you have to pick up the same rocks over and over again. One peculiarity of our location is that ALL the stones are soft sandstone. So some genius ran a roller-type rock crusher at the back of the digger and it just turned the rocks into sand. I still don't know why that didn't catch on with farmers. Of course, it wouldn't work as well with granite boulders or any rock much tougher than sandstone...
BOB
