At the recent York train meet, Al Zamorski of Millhouse River Studios demonstrated his new rotary coal dump using Brennens real coal. There is no dust, and the coal is large enough and heavy enough to dump without flying all over. The coal is a bit larger then the more common 'Chestnut' coal, but all different sizes of coal were hauled in hoppers. A material I use is Black Beauty sand blast grit, which can be found at building supply places. The fine grit is scale sized for Chestnut. However, there are some different colored bits, and some tubular shaped bits that I remove when making loads.