One company I know and have done business with for 15 to 20 years . Told me they figure it cost them forty dollars a ton after it come across the scale . TO unload grind up and load in the railcar . Labor overhead etc . This was back in 2006 or 2007 when the volume was better. Plus most shredders are run so close of margins . They make their profit on the down stream system . The alum brass copper etc they pick out . Plus the fluff or trash in the metal on average in 30 percent or more at times . Which you buy then pay to get rid of . Customers are pull more non ferrous out of their loads .