Hello Dennis, where in Michigan are you?? If you call Hitzer direct to the factory, the number is on their website, they will help you, I called them once, had a 15 minute conversation with the owner, and I'm not even a Hitzer owner !! See if you are near a Hitzer dealer so you can go look at a similar stove. There is or was a dealer just west of Grand Rapids, sells bagged coal too. He had several Hitzers in stock when I visited him.
Your stove should have grates between the firebox and the ashpan. There is a handle on the outside that attaches to the grates, so that they can be 'shaken' to get the coal ash to fall into the ash pan. I can't imagine why the grates would have been removed.. Look around the house they should be around, they are heavy cast iron and wouldn't be tossed away buy accident, or at least Ihope not.
The hopper usually is set into the stove from the top, through the top loading door. NOTE; the rope-like gasket MUST be in good shape on this loading door if you use the hopper load feature of this stove..
Nut coal is what the Hopper feed stove likes, I'm not sure if it will burn the next smaller size of anthracite, which is Pea.
Anthracite coal comes only [99%] from eastern Pennsylvania. So it has to be trucked in in our state. There are coal retailers, Family Farm and Fleet, some TSC's have bagged coal. Bulk is available from some retailers in Northern Ohio and Indiana.
The cost to burn coal [the amount burned per day] varies widely, it depends on the house [size], the quality and quantity of insulation, weather stripping, windows , and of course the weather,. today it's supposed to be in the 40's, the stove would just idle along, maybe burn 20-30#, but tomorrow night it's supposed to be in the teens with high winds, so the stove may burn double or tripple, depending on the house and heat needed.
So where are you located in Michigan?? I'm just south of Flint.
Hope the above helps..