Surface – Dimension Stone – On Monday, October 23, 2017, the boom of a Pellegrini stiff leg derrick failed while lifting a muck bucket. The crane operator and the foreman were in the operator’s station, or “crow’s nest,” on the edge of the high-wall. As the boom started to fail, they were able to run to safety before the operator’s station was crushed. The derrick collapsed into the quarry, but no injuries occured.
Best Practices
• Do not overload the crane. Know the load chart and weight of the object to be lifted in order to avoid tipping or causing structural damage to the crane.
• Periodically inspect the crane in accordance with the procedures in the operator’s manual.
• Follow the manufacturer’s guidelines when making repairs or conducting other maintenance on the derrick.
• Examine and test all safety devices on a regular basis and ensure that they are operating properly.
• When using cable clips to secure a wire rope, always apply the proper torque, use the amount required based on the rope diameter, and follow the rigger’s rule of “never saddle a dead horse” when positioning the clip.
• Never side load the boom by rapidly swinging the load or picking up a load when it is not directly under the boom tip. Side loading the boom could cause a collapse.
