A truckmixer owned by an Independent Haulage Contractor (IHC) was stopped from working when it developed a noise thought to be originating from the gearbox on the drum.

On closer inspection, it was found that some of the mounting bolts from the drum mounting flange to the gearbox were missing; only 4 out of 12 fitted bolts remained.  The truck mixer had a new drum fitted 8 months earlier, however no formal maintenance inspections were subsequently carried out on this area of the drum.

If the drum had broken free while the truckmixer was travelling on the highway, it had the potential to result in a very serious incident.

KEY FINDINGS

Safe Systems - After the repairs were carried out, the driver was advised the mounting flange should be regularly inspected; however, this doesn’t seem to be common knowledge.

Inspection and maintenance - All transit mixer drums are supplied with an original equipment manufacture (OEM) handbook, which highlights all required maintenance activities and schedules.

Inspection and maintenance- All drivers should visually inspect the mixer gearbox mounting bolts (as per picture 1) as part of their daily pre-use inspection, checking for signs of movement or missing bolts.

Tools and equipment - This type of incident appears more likely to occur following the removal of the drum

Picture 1

HOW COULD THIS HAVE BEEN AVOIDED

• Operators must ensure they follow OEM maintenance schedules in accordance with the specific equipment operators guide (drivers handbook).
• Best practice is to have this area checked during the formal documented safety inspection by the vehicle maintenance provider in accordance with the truckmixer inspection sheet ( to view this pdf please click on additional pdf that is linked to this incident on the Safequarry website).
• Ensure robust defect raising and rectification regimes are in place, which should be audited and checked by the vehicle owner.