of the roller mill housing 24 encloses a centrifugal spinner plate 30 which is aligned with the venturi feed tube 31 to direct the incoming coal from the feed pipe 32 initially onto the spinner plate 30 where the centrifugal action moves the large and fine particulate outwardly into the annular space 25 so the fines are lifted and stripped from the coarse particulates which fall by gravity through the annular space 25 and proceed into the grinding chamber for reduction the supply of coal reaching the feed pipe 32 comes from a supply bunker 34 which feeds the coal into an enclosure 35 where it falls onto a weigh belt apparatus 36 driven by a suitable motor 37 to deliver the weighed amount of coal to the outlet 32a which is connected to the pipe 32 the weigh belt has a sensor 36a connected by lead 49a to controller 49 a supply of hot drying air is introduced to the system by fan 38 driven by motor 39 which delivers such air into concuit 40 and a portion of that air is split off by a control valve 59 and flows through conduit 41 to enter the roller mill bustle 42 where the hot drying air at velocity will strip the fine particulate matter entering at the pipe 32 into the roller mill outlet stack 43 where it enters the outlet delivery conduit 44 hot drying air from line h tempered by ambient or other air admitted at line c can have a temperature of from 400 u00b0 f to 900 u00b0 f depending upon the drying requirements suitabe motor operated valves hv and cv are provided subject to controller.