I dunno, very "clean" to be a cement mixer. Not much dust on it. Wheels look like they only have six lugs which isn't all that heavy duty. Frame is built pretty strong. Looks like the back hopper raises up to dump something in the back of the drum, but the chute in the front is very high and the drum almost looks like it is angled to the back. The chute appears to be adjustable. The axle on top has chain drive on one end and the other end looks like a big belt. The top has a "lip" on it that suggests something is poured in from the top. I'd like some more photos but here are my guesses:
Deffinately a mixer of some kind. Dry fertilizer blender? Seed blender? Seed innoculator? Feed blender? Lime cruncher? Mortar mixer? White wash mixer? Cleverly disguised still? Think horses not zebras, cement mixer.
The 'Bonker