Prosecution Details

[1] Being the owner of a crane used for multi-crane hoisting, failed to assign a person to supervise the hoisting.

[2] Being the owner of a crane used for multi-crane hoisting, failed to ensure that the safe working load of the crane, for the required boom length and radius, exceeded the calculated share of the load that was taken by the crane by at least 20%.

The investigating inspector observed on site that a 10 tonne SWL Greirson tractor crane was laying on its side with the rear part of the crane jack knifed in a vertical position.

On 21 August 1996 the two, 10 tonne SWL tractor cranes had been attempting a dual lift moving a conveyor truss weighing 7.49 tonnes approximately 600 metres. The Linmac tractor crane had been travelling in reverse and the Greirson tractor crane was trailing with the load but operating in a forward motion. As the two tractor cranes came down the side of the factory, the leading Linmac crane commenced to drive forward towards the laydown area whilst the Greirson tractor crane attempted to turn fully to the left hand site. It was at this time with the dogman who was trying to position the conveyor truss onto the skids, that the Greirson tractor crane commenced to topple over dragging the conveyor truss approximately a metre to the left nearly trapping the dogman.
The inspector assessed that there had been a lack of supervision in regards to the dual crane lift by management. Also, both crane drivers did not know the proper reduction to be made for a multi crane lift and it became evident that the driver and dogmen had not carried out a thorough check to ascertain as to whether the cranes were adequate for the 7.4 tonne load. From the investigation both tractor cranes had been overloaded during the dual crane lift.

The two crane drivers attended a certificate of competency hearing and had their certificate of competency to operate a non-slewing mobile crane suspended for a month pending them re-sitting and passing the assessment requirements.