The Conveyor Equipment Manufacturers Association (CEMA) has published a revision to its industry standard for conveyor troughing and return idlers. CEMA Standard 502-2004 "Bulk Material Belt Conveyor Troughing and Return Idlers, Selection
and Dimensions" is available in PDF format for $30 from CEMA's Web site http://www.cemanet.org
CEMA has also published a Conveyor Safety Compact Disc (AV #6) that provides safety guidance for working around screw and drag conveyors and bucket elevators. It is available for $20 from the Web site.