A Rough Terrain crane overturned at the end of May on an oil sands project north of Fort McMurray Alberta, Canada, while carrying out a tandem lift with an excavator.
The crane a Grove RT875E was lifting a piling casing and was in the process of lowering it to the horizontal with the aid of a John Deere 350G excavator. The excavator was hooked onto the bottom of the casing and was travelling backwards raising it as it moved, while the crane operator was lowering his end.
The overturned crane
It seems that the crane controls locked out – possibly due to a dynamic overload? But the excavator kept on going, pulling the crane over onto its side. There was no communication between the crane and excavator operators and no signalers or radios were in use.