My Lab made my backyard into what looked like some kind of WW1 movie set, with 3' diameter holes all over the place. He always had one that was close enough to the faucet to fill it up and make a mud bath for him. I think his rheumatoid arthritis stopped him after 3 years of it.
My Pit mix would have been the ultimate digging machine, but he didn't care much about it. One time he saw a Mole and dug a huge hole trying to catch it, but never did. I think he maybe dug a dozen holes in the yard during his entire life, but he sure dug them fast. Those huge claws and thick short legs really could move the dirt.