You would be surprised how well a chainsaw cuts dirt(not rocks). I have a little plastic saw with the 3/8 narrow round corner chain, and I try to cut with the top of the bar, to shoot the dirt out if I can. It's done a few stumps and sharpens up not bad still, I just file by hand, half way through if necessary and the chain seems to last quite a while. It just gets used for small jobs as it never did cut 12"+ hardwood well, but that's done with a different saw. If you have a pressure washer or even a hose you can clean the stump up a bit and not cut quite as much dirt.