Worker struck by mobile crane hook block
In February 2023, a worker was injured after being struck by a hook block after it fell approximately eight metres from a mobile crane.
Early investigations indicated the crane operator had begun telescoping the jib outwards when for reasons yet to be established, the main hook block contacted the head of the boom (commonly known as ‘two-blocking’) which led to the failure of the main hoist rope. As a result, the hook block fell and struck a worker.
Investigations are continuing.
These findings are not yet confirmed, and investigations are continuing into the exact cause.
Safety issues
In Queensland, there have been several incidents in the past few years where hook blocks have fallen due to the hoist limits not functioning as intended.
Irrespective of the type of crane and hoist limit device, correct operation of the hoist limit is important to avoid major safety issues.
Ways to manage health and safety
Effective risk management starts with a commitment to health and safety from those who manage the business. If an incident occurs, you'll need to show the regulator that you’ve used an effective risk management process. This responsibility is covered by your primary duty of care in the Work Health and Safety Act 2011.
Use the hierarchy of controls to help decide how to eliminate and reduce risks in your place of work. The hierarchy of controls ranks types of control methods from the highest level of protection and reliability to the lowest. It’s a step-by-step approach to eliminating or reducing risks. You must work through the hierarchy of controls when managing risks, with the aim of eliminating the hazard, which is the most effective control.
Possible control measures to prevent similar incidents
A principal contractor has a duty to ensure the overall coordination of the lifting operations at a workplace. This includes ensuring systems are in place for communication between all PCBUs and workers at the workplace.
Crane Owner
A crane owner’s responsibilities include, but are not limited to ensuring:
- there’s a thorough equipment maintenance and inspection program
- equipment is maintained and inspected in accordance with the crane manufacturer’s requirements and the requirements of the Mobile crane Code of Practice 2024 (PDF, 2.29 MB) and other relevant technical standards
- that only people with the appropriate mobile crane licence class operate the mobile crane (additionally, the crane owner who employs crane operators should also ensure the operators have undergone familiarisation and refresher training as required under the requirements of the Mobile crane Code of Practice 2024 (PDF, 2.29 MB)
- all relevant information regarding the mobile crane is provided to all relevant workers before work begins.
Planning and coordinating mobile crane operations
Planning for mobile crane operations should start as early as possible. This involves:
- consulting with everyone involved (for example, the crane hirer, crane supplier, engineer and crane operator, and dogger and or the riggers)
- ensuring the type of mobile crane selected suits the particulars of the lift
- determining the size of the crane crew via a risk assessment and implementing appropriate controls, especially in relation to minimising the risk of collision between the crane and other plant, and loads contacting other structures, overhead powerlines or workers
- not siting a mobile crane until carefully considering if it:
- has adequate capacity to lift the load at the maximum radius
- could collide with other plant and structures.
- using a reliable method of communication between the crane operator and dogger
- providing all relevant information, training and instruction before work begins (Toolbox meetings are one way to consult and discuss tasks with workers).
Crane motion limits
The crane is to be fitted with motion limiting devices on crane functions where damage to, or failure of, the crane could occur. The device that prevents the hook block from contacting the boom head (“anti-two block”) is to be of the types that stops operation of the hoist, luffing and telescope functions of the crane before contact with the boom head (i.e., two blocking) occurs. Anti-two block switches, which provide a visual and/or audible warning only, are unacceptable and should be replaced as soon as possible with motion cut devices.
Safety features, including hoist limit functions, may need to be temporarily overridden for rigging purposes (e.g., when setting up or packing up the crane). Once these tasks have been completed, all safety features and functions provided by the crane manufacturer must be set to the correct modes for normal operation of the crane.
Crane Operator
Crane operators must have a comprehensive knowledge of the operating capabilities of the crane and be competent to carry out the lifting operation. It is a must for crane operators to:
- know the particular model of crane to be operated, its characteristics, functions and limitations
- know the information in the crane’s operating manual
- ensure loads are evenly balanced and well secured
- hold the appropriate high-risk work licence for the type of crane being operated, and complete refresher training as required
- know proper inspection and maintenance procedures to be followed in accordance with the guidelines of the manufacturer and owner
- complete a pre-operational visual inspection and functional test before the commencement of each work shift, including inspecting and testing the following:
- all relevant items indicated in the operations manual
- operating and emergency controls
- brakes
- safety switches and interlocks, including motion limiting and indicating devices
- visual inspection of the structure
- wire ropes to ensure they are sitting correctly on the drum and correctly reeved on the sheave.
The results of the inspection must be entered into a logbook and kept with the crane.
Exclusion zones
Exclusion zones should be established around mobile cranes and adjoining areas to prevent people from entering the area. The size of the exclusion zone should be based on a written risk assessment.
Where the exclusion zone requires closure of a public footpath or roadway, written approval must be obtained from the relevant authority, and people should be safely directed to an alternative footpath. Lane closures and other operations that require the erection of barricades and signs should comply with the requirements of Department of Transport and Main Roads, local government authorities and any relevant building or local Acts.
Inspecting and maintenance
Routine inspection and maintenance should be carried out in accordance with the crane manufacturer’s instructions. These inspections may consist of a program of weekly, monthly, annual and major inspections, and should include but not be limited to:
- all functions and their controls for speed, smoothness of operation and limits of motion
- all emergency and safety switches and interlocks, including limiting and indicating devices
- visual inspection and measurements as necessary of structural members and other critical components such as brakes, gears, fasteners, pins, shafts, wire ropes, sheaves, locking devices and electrical contactors
- tyre wear and condition
- ensuring lifting hooks have operable safety latches
- structural and mechanical parts of the crane.
Inspecting and testing of mobile cranes should also include annual inspections and 10-year major inspections.
A PCBU must minimise any remaining risk with suitable personal protective equipment. For example: hard hats, protective footwear, eye protection, safety vest.
The control measures put in place should be reviewed regularly to make sure they work as planned.
More information
- Mobile crane Code of Practice 2024 (PDF, 2.29 MB)
- Managing the risks of plant in the workplace Code of Practice 2021 (PDF, 1.57 MB)
- How to manage work health and safety risks Code of Practice 2021 (PDF, 0.65 MB)
- Cranes specific legislation (PDF, 1.34 MB)
- Safety alert - Mobile and tower crane hoist limits
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