PLANT AND EQUIPMENT • result in extreme wear on the belt , degrading the main fireretardant layer and exposing the heat-sensitive materials found in the belt ’ s inner construction .
Controlling fugitive material Fugitive material control and regular cleaning of spillage are imperative . Without proper belt cleaning , chute sealing and belt tracking , spillage that collects around the loading / discharge areas and along the belt path can damage moving components , restrict access by fire crews and potentially act as fuel .
Dust control is extremely important when handling combustible substances , and it is recommended – instead of just taking into account the fire triangle – operators consider the “ Dust Explosion Pentagon .” Examples of highly combustible materials include :
• Coal – carbon-based , highly flammable material that burns at high heat , with dust that is easily ignited by a spark .
• Petroleum coke ( petcoke ) – carbon-rich derivative of oil processing , used as a coal alternative for power generation , among other applications . In dense concentrations , the dust is combustible with a high-energy spark .
• Cellulose – a naturally occurring polymer found in wood , paper and grains ; dust readily ignites .
Significant amounts of dust can collect on the walls of the loading zone chute . If a foreign metal object is accidentally introduced into the enclosed area , a spark can potentially create an explosion . Additionally , common maintenance within the chute such as removal of the wear liner using a cutting torch often requires confined space entry by workers . If the inside of the chute is not adequately cleaned , this task could pose a serious hazard .
Possible ignition sources
Friction
• Frictional heating of belts riding on non-rotating components
• Heat from brake friction
• Belt rubbing on structure
• Bearing seal failure leading to seized bearings
Dust / material / chemical
• Combustible dust
• Out of control high-temperature processes where bulk material temperature exceeds belt capability
• Spillage of combustible bulk materials
• Accumulations of bulk materials that can spontaneously ignite
Mechanical / maintenance
• Slip of a belt on a pulley
• Cutting and Welding
• Mistracking
• Excessive temperature of the drive
• Hot surfaces
• Flammable liquids • Sparks and electrical causes
Think like an inspector When examining conveyor equipment , one should approach the task with the same critical mindset as an inspector from OSHA , MSHA or the local fire department . Safety professionals recommend a holistic view of the system and the combustibility of the material . When making a conveyor fire risk assessment , also consider :
• Spillage levels and cleaning schedules .
• The conveyor ’ s proximity to workstations .
• How the conveyor design ( enclosures , narrow walkways , etc .) could create a hazard for employees .
• Safe storage of flammable liquids .
• Compliant signage .
Considerations for conveyor fire prevention Often the potential return on investment ( ROI ) for prevention equipment is not recognised until managers are inspecting burnt rubble and negotiating with insurance adjusters . However , safetyminded operators understand that the same equipment they would implement for increased efficiency such as belt cleaners and impact cradles , can also help prevent fires .
• Impact cradles and support cradles help reduce fugitive material by providing a flat , stable belt surface that facilitates effective sealing .
• Transfer chute design is a critical element of fugitive material control , with sufficient settling zones and confinement . New raised chute designs also allow for external wear liners that eliminate the need for confined space entry or torch removal . When paired with improved skirt seal designs , fugitive spillage and dust emissions are drastically reduced .
• Modern belt trackers detect mistracking and correct the belt path immediately using troughed idlers or gripping return idlers .
• A heavy-duty belt cleaner system featuring modern primary and secondary cleaners with an effective tensioner increases the volume of discharge and limits the amount of carryback and fugitive dust . Along with limiting spillage , tail pulley health is improved and there is less fouling of rolling components .
Conclusion Operators should regularly contain airborne dust at transfer points and remove accumulation . Damaged rollers must be replaced promptly . Conveyor belt alignment is also an essential prerequisite to belt safety . Consider using flame-resistant grease and other lubricants . Fire detection and suppression systems must be tested in accordance with regulatory standards . Experience has shown that clean conveyor systems and ongoing maintenance form the best defense against fire .
References :
1 . https :// foundations . martin-eng . com / safety-bookdownload ? hsLang = en 2 . https :// foundations . martin-eng . com / learningcenter ? 3 . Rowland III , J . H . and Smith , A . C . “ Flammability of wider conveyor belts using large-scale fire tests ”. National Institute for Occupational Safety and Health ( NIOSH ), Pittsburgh , PA . 2010 . https :// www . cdc . gov / niosh / mining / UserFiles / works / pdfs / fowcbu . pdf
4 . Fernández , Marta ; Rodriguez , Ángel . “ Early Detection and Fighting of Fires in Conveyor Belt .” Edaffic . Publications Office of the European Union , EUR 25364 . Luxembourg , 2013 . https :// publications . europa . eu / en / publication-detail / - / publication / 2684b552-3658-446e-aa0f-
030ff7b98e6c / language-en
Significant amounts of dust can collect on the walls of the loading zone chute . If a foreign metal object is accidentally introduced into the enclosed area , a spark can potentially create an explosion . www . africanmining . co . za African Mining Publication African Mining African Mining • January 2025 • 67