It reminds me very much of my Iron Fireman stoker... I looked on the website for an exploded-view or parts diagram, but couldn't find one.
It is mentioned that it is 'a chain drive'. I'm not sure if that is for the motor/transmission or if it is for the coal delivery.. I'm assuming it still uses an auger to push the coal to the burn pot.
If I had your Bituminous coal with the low swelling index, and low price and close proximity,, I'd be burning it for sure.. I have the stoker, and the boiler... but Bitum is roughly $120/ton delivered, and good anthracite is $200 delivered.. so putting up with the hassle of bituminous from my area, [soot,swelling and clinkers, high ash, etc] just isn't worth it..
But I believe your Wyoming Bituminous would burn just about as easily and reliably in an underfeed stoker as anthracite does in mine.
as the saying goes.... location, location, location....