Object falling from height
- Safety Flash
- Published on 30 November 2005
- Generated on 13 February 2026
- IMCA SF 11/05
- 1 minute read
IMCA has received a report of an incident wherein a ‘banana sheave’ roller weighing 4.5 kg came loose during operations.
What happened?
The roller fell some 24 metres from the derrick and hit the drill floor. Nobody was injured.
What were the causes?
The immediate cause of the accident was identified as being that the bolts which attached the rollers to the sheave had loosened.
The underlying causes were noted as:
- insufficient design
- insufficient maintenance
- lack of documentation and drawings describing that the sheaves should be function tested
- insufficient description of responsibility for involved personnel
- insufficient maintenance management and follow-up relating to lifting equipment.
Lessons learnt
The following points were noted:
- Lifting equipment should be examined and valid certificates for equipment in use should be presented.
- Inspection and maintenance should be performed on all sheaves that are in operation, with nuts and bolts inspected.
- All bolts on rollers should be fitted with protective pins to stop the bolt from loosening;
- The contractor’s planned maintenance management system in place should be reviewed accordingly.
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