Hello, and welcome to the forum.
Get a comfortable seat, and take a look at this thread: EFM = Electric Fireman (new project alert)
This is a Hybrid boiler that would do exactly what you are describing that you want to do..
The other option would be to try to find an old Prill or WillBurt underfeed stoker..
Finding out what your locally available coal's burning characteristics are is very important with what type of fire box, stoker feed, and
ash handling system you want and need..
There was a test done with an EFM boiler, using a Prill type underfeed/rotating grate stoker.. I dont know if EFM is going to start to produce these
units or not. Look in the EFM manufacturers forum for the info.
I'd keep an eye open for an older unit on Craigslist or your local papers.. also, check with several HVAC companies, they may run across an old unit that is destined to be scrapped, and you can rescue the stoker and boiler/furnace for your labor..
I'd PM europachris, the engineer that did the Hybrid boiler in the above linked thread, and see if you are getting coal from the same places..
Best of luck,, Greg L