CONVEYOR BELTS; COMPONENT PARTS OF CONVEYORS, NAMELY, CHUTE AND CONVEYOR BELT SEALING SYSTEM COMPOSED OF PROTECTIVE LINERS, GASKETS, MOUNTING BRACKETS AND SCREENS AND ASSOCIATED UNDERFLOW CHUTES FOR BULK MATERIALS HANDLING; PARTS OF A CONVEYOR BELT SYSTEM FOR BULK MATERIALS HANDLING, NAMELY, PROTECTIVE SKIRTBOARDS