I have a hole in my yard that I am not really sure if there had been a tree there at one point or not. I put dirt in the hole and was going to use a 3 ft. walking stick to push it down and pack it. The stick would push all the way down in the ground the whole 3 feet. I got a little worried that I might have a sink hole instead of a stump hole. Is it common for a stump hole to be that deep??? Thanks for your help!