Alert 09 – 06 Dropped Object – Rigging Screw Jaw End

Alert 09 – 06 Dropped Object – Rigging Screw Jaw End


Two workers were assigned with the task of fitting rigging screws between the top drive torque tube track and the mast on both the driller’s and off-driller’s side. Prior to climbing, both workers donned their safety harnesses and attached a safety lanyard from one end of the rigging screw to the D ring at the front of their harness. This meant that, when climbing, the rigging screw would have been vertical with the tied off jaw end at the top and unsecured-end running down the right hand side of the person’s body, ending around his thigh. When the second worker climbed the derrick ladder to a height of approximately 40 feet above the floor the unsecured jaw end at the bottom dislodged and fell to the ground (approx 60 feet). The jaw alone weighed 2.3 kg and landed 9 meters out from well-center on the driller’s side in line with where the V door meets the catwalk and only 10 feet away from a tag-line operator assisting a crane lift. The floor was clear of all personnel prior to the job commencing except the Assistant Driller, who was supervising the job. It is important that the terminology used throughout in relation to rigging screws / turnbuckles is understood.