I didn’t know that this was the reason for their development and demise.
Rick;
Oddly enough, history repeated itself without the human sacrifice in the early 1970’s. Pennsylvania Power and Light found they could generate 33% more BTUs in the fireboxes to their steam turbine generators by adding pulverized culm to the fuel oil, and the culm banks diminished again. (But the abrasion factor had to be significant.)
Regards, David Meashey
I wonder how they figured out adding a waste product would be useful. It’s sort of like Vegemite, but coal.
Interesting bit of knowledge. Some will also enjoy the shots of older freight equipment with cars of all sizes mixed together. 
i was not abel, to find that word - save a mention, that Vegemite must be a very, but very very southern thing.
is it something marsupial?