If I was building a new house and live have access to free bit. coal here's what I'd do:
0. I would certainly use bit. coal to heat my house.
1. I'd definitely go with infloor hydronic heat.
2. I'd have an outside boiler. Close to house is better to reduce heat loss in piping and keep material costs down. But you can go hundreds of feet from the house and still be fine. The piping just gets expensive. Keeping the stoker outside keeps the mess out of the house.
3. I'd definitely use an underfeed stoker to heat the boiler.
4. As most have said, bit. coal quality and burn characteristics vary alot. It would be nice if you could find someone that burns local bit. coal in a stoker and see how it works. Volatile content, percent ash, btu/pound, fusion temp, etc are all important, though some aren't too important for an underfed stoker.
If you had a large coal bin, and had a way to easily get the coal into it (tractor loader, skidsteer, auger, kids and shovels
, etc), you could go weeks without adding coal to the bin. The ash may need to be done more often. In warm weather, I can go 3 days or so between emptying ash. In cold weather, I do it twice per day. But I use high ash coal (20%), and have a small ash pan. Most coal has half the ash I have.
I use about 5 or 6 tons per year to heat a 1750 sq.ft. home, 1980s era. My stoker is indoors, and is just a forced air unit with no ductwork. It heats my entire tri-level home well. I use 40 lbs or less per day in early fall/late spring, and 100 lbs per day or more during subzero weather. I send alot of heat up the chimney as my heat exchanger is pretty inefficient. With a really efficient stove, I think I could heat the house with 3 or 4 tons per year. But for $45 per ton, I can't justify spending too much to gain efficiency.
As far as I know, you options for stokers are:
1. Find a used underfed stoker/boiler. Brands I know of, most not in production: Prill (like mine, WY made), Hardin (Montana Co, out of business), Stokermatic (Utah-made, you can find some used units there). The link given in an ealier post to Pease Feed and Coal in Powell, WY can get you to a person who could refurbish a boiler/stoker unit for you. It costs quite a bit though. You can likely find other brands if you do some digging, mostly in western states. I think there were some outfits in North Dakota and Canada as well that have gone out of business. If you're patient, and willing to travel a little, you will eventually find a used stoker and or boiler.
2. Buy a new underfed stoker/boiler. The only 3 I'm aware of are Legend http://www.legendmfg.ca/order3.htm
, Wilburt out of Ohio, and EFM heating. There is a guy in WY where I live heating a large pawn shop with hydronic heat and he uses a Legend.
Good luck. You'll learn alot here if you just spend some time and ask questions.
Steinke in WY