That is a lot of cinders: one out of every roughly 10 to 30 cars of coal. Who was takeing all that cinder "waste"? They used mine and blast furnace slag "waste" crushed for roadbeds.
Al Kresse
In the North/Northeast, I'm sure a good portion of it was used for traction control on roads in the wintertime. I know my grandfather kept a bucketful of ash (wood) from his pot-belly stove in the garage for spreading on the driveway in winter. Don't know percentages though.
