CRRM uses the Hesperus coal. Sometimes the lumps arrive a bit large, but give a couple of small children a couple of hammers, and the coal is soon reduced to proper size. Being a museum, we proudly cling to the child indenture that was common in collieries in the 19th Century! Well, not really. But the younguns jump on the opportunity to pound on things and get away with it.
My observation is that the Hesperus product burns hot with very little smoke except when first moving away from a station stop. But the coal's natural properties, plus the locomotive front-end and stack screens sure produce quite a "rain" of 3/8"-sized cinders. They are cold when they land, so the fire danger is low. But a shower and shampoo are certainly necessary at the end of the day.
Mike