We used to have an anthracite boiler in the house when I was a kid. But this was a dedicated boiler meant for this fuel and no other (we lived in a Smokeless Zone) and the burner was fan-assisted. It would not have worked with ordinary coal or coke.
As far as I can recall, my father had no difficulty lighting the thing. The anthracite was fed from a hopper above controlled by a baffle. To light it, he would empty the combustion chamber and lay out paper and firewood to start off. Once it was well alight he would let down a little fuel from the hopper and turn on the fan. It would usually start up OK first time. If too much fuel was let down too soon, there would be a build up of coal gas and there would be a minor explosion in the fire chamber - causing the door to fly open and hot coals to be scattered all over the kitchen.
Furthermore, if the supply of oxygen were obstructed in any way (e.g. by too much clinker), the boiler would emit sulphurous fumes (probably laced with CO) into the kitchen - or the fuel in the feed hopper would start burning of its own accord.
Periodically one had to remove the clinker - something that could be done whilst the fire was still alight, though a bit hazardous!
All in all, I reckon that boiler would have failed every H&S test in the book if it were in use nowadays. But it did keep the house warm and heat our water...
