Pit & Quarry, April 2010

C O N V E Y I N G M A T E R I A L H A N D L I N G Figure 1 The pinch point is defined as the area where the rotating roll meets the moving belt Two moving parts come together forming a pinch point designed and installed return roll guard will effectively eliminate accidental contact with the area In addition returnroll guards are required where return rolls may work loose from the brackets fall to the ground and presumably injure a miner such as over a catwalk or a roadway The MSHAs Guide to Equipment Guarding states that an effective machine guard must Be considered a permanent part of the machine or equipment Be installed as close to the machine part as feasibly possible Prevent access to all moving machine parts Be designed for the specific job and specific machine Be designed and fabricated to the extent practical to such dimensions and weights that one person is able to physically install and remove the individual guard components Be constructed and maintained to withstand vibration and shock during normal operation Not present a hazard in itself The Guide additionally states Return rolls must be guarded if someone could contact them while working or passing underneath the belt It is reasonable to expect these types of accidents where persons or tools can contact the idlers The primary objective of any returnroll guard is to help prevent injury to personnel This is the most important issue to address when moving toward compliance with the code The properly designed guard should also provide peace of mind to those working around the area and help to alert them to the potential hazard that exists at the location The design must be simple to install and allow the roll to be inspected and maintained with ease Leading edge return roll guards are constructed from single pieces of metal plastic or in some cases old skirt board and attached to the leading edge of the roll to introduce a barrier between mine personnel and the pinch point These guards do not provide full protection from the dangers of the pinch point and Take note A properly designed return roll guard should provide peace of mind to those working around the area and help to alert them to the potential hazard that exists at the location The design must be simple to install and allow the roll to be inspected and maintained with ease www pitandquarry com April 2010 PIT QUARRY 13