IF YOU WANT TO MODEL REALISTIC PILES OF COAL OR YOU WANT TO GLUE IT TO TENDERS, HOPPERS AND THE LIKE, USE REAL COAL SLAG. AVAILABLE IN DIFFERENT GRDES, DUST FREE, AND CAN BE VERY COST EFFECTIVE. IT IS USED AS A BLASTING MEDIA. A 50LB. BAG COSTS AS LITTLE AS $9.00 FROM NORTHERN TOOL. I USE IT FOR HOPPERS & PILES, VERY NICE.
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