The const. co. I work for one time had a sod forklift stolen from a sod field we were cutting, and later that weekend, the sheriff found it for us while theye were in the helicopter looking for some lost hikers... only the very top flat part of the cab was above the muck.. looked like a 2' x 2' yellow carpet on top of the muck.
Suprisingly enough, they pulled it out( no small chore... ), cleaned out the exhaust pipe, and air cleaner, and it fired right up..
For the big excavators like that, in muck areas.. we use big matts made of 8x8 rough cut oak, 'sewn' together with 1' steel cable. works great.
Soundguy