Maybe you do need an excuvator. Stand on it, that is thick! But if you are a cheap or broke as I am and have a tractor, do you think that you could hack a piece where a pipe with some kind of wire or a hog panel was attached and with other pipe on the top drag some of it out at a time until it breaks up. You would still need a john boat or something.

But good luck on whatever you decide.

I wish I had the tenacity of GSF!