FACTORS CONTRIBUTING TO STICKY COALS DURINGWAGON UNLOADING FOR QUEENSLAND COALS

摘要

Queensland Rail (QR) hauls in excess of 100 million tonnes of coal each year fromQueensland mines. Some coals (“sticky coals”) do not flow freely from bottom dump railwagons in the trains and hence impede unloading. When coal hangs ups in the wagons, itneeds mechanical assistance (jackhammering) to break the arches that have formedacross the doors that stops unloading. Three field expeditions were conducted to establishthe factors that contribute to this problem. Eight coals and ten wagon types were audited.Three coals were free flowing under all circumstances and the other five showed varyingdegrees of stickiness. Coal properties, loading and travel forces and coal wagon design,affected the position and the strength of the arches in the wagons.