In August 2021, a worker died after being struck by a mobile crane in pick-and-carry mode (lift and shift). Early investigations indicate the man was acting as a dogger and in control of a load when he was holding a tag (tether) line attached to the load that was being relocated at a workplace. It appears the worker was walking between the front of the mobile crane and the load when he was hit by the crane.
These findings are not yet confirmed, and investigations into this incident is continuing to determine the exact cause.
Being positioned between the load and a moving mobile crane is very hazardous. If the crane operator’s view is temporarily obscured, or the operator is momentarily distracted or the worker stumbles, the risk of that person being run over is high.
In Queensland, there have been a worrying number of mobile crane incidents involving crane rollovers, people being struck, structural failures and loads falling.
Many of these incidents have occurred due to poor planning of the lifting operation, often because basic factors have been overlooked.
The use of a mobile crane can be hazardous, particularly as the complexity of the lift increases. If the work is high-risk construction work (as defined in the Work Health and Safety Regulation 2011), work method statements need to be prepared for the mobile crane operations and are important for pre-planning to help reduce the risk of an incident.
Ways to manage health and safety
Taking steps to manage risks is a workplace health and safety duty of doing business in Queensland. 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
Using a mobile crane on any worksite introduces the risk of collisions if sufficient clearances or exclusion zones are not maintained around the crane and load. Collisions can occur when the mobile crane (including placing of the load) is being operated in close to other plant, overhead powerlines, buildings, and workers on site, including members of the crane crew. Often when a mobile crane hits a person serious or fatal injury occurs. The risk to people increases when the operator’s visibility is impaired due to travel direction, or size and shape of the plant and load.
Specifically, in relation to doggers walking with a pick-and-carry mobile crane:
- Initially see if the tag line(s) can be tied to the front of the crane to eliminate the need for the dogger to hold the end of the tag line.
- The dogger should never be in the travel path of the crane.
- The crane operator should stop the crane if he or she loses site of the dogger.
Planning and coordinating mobile crane operations
Planning for mobile crane operations should start as early as possible. This involves:
- consultation with people engaged in the work, such as the principal contractor or crane hirer, crane supplier, engineer and crane operator
- ensuring the type and number of mobile cranes selected suit the particulars of the lift
- determining the size of the crane crew by undertaking a risk assessment and implement 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 at the workplace
- using a reliable method of signalling between the crane operator and dogger
- using documented lifting procedures to help to define responsibilities and approach the crane lift in a logical, systematic way. Safe work method statements must be prepared for a range of high risk construction work associated with cranes
- implementing effective exclusion zones 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. If the exclusion zone requires closure of a public footpath or roadway, approval must be obtained from the relevant authority.
Precautions with pick and carry cranes
- When moving a load in the pick-and-carry mode, the dogger should remain in sight of the crane operator, and not walk in the path of the crane.
- Always travel slowly to prevent excessive swinging of the load. The load should be carried as close to the ground as possible, and should not lift higher until it is almost in position.
- Where possible, avoid travelling the mobile crane across slopes or over potholes, depressions, soft ground, road chambers or shoulders, rail tracks, dunnage wood or any objects, as these could destabilise the crane or load.
It is a must for crane operators to:
- have a comprehensive knowledge of the operating capabilities of the crane
- be competent to carry out the lifting operation
- ensure it is driven to suit the environmental conditions and slow enough to retain control in unexpected circumstances
- reduce speed before turning or applying brakes
- watch out for ditches, embankments, ground depressions as overturns can occur
- ensure loads are evenly balanced and well secured.
- thoroughly check safety devices and audible working alarms of mobile plant prior to commencing any work
- hold the appropriate high risk work licence for the type of crane being operated, and completed refresher training as required
- know any workplace conditions that may affect crane operation, including ground conditions, the presence of overhead powerlines, nearby structures, cranes and concrete placement booms.
The primary role of a dogger is to assist the crane operator in the safe and efficient operation of the crane, including the safe slinging of the load. The dogger’s role is crucial when the crane operator’s vision is obscured, or when operating in high-risk areas. A dogger should be positioned to safely observe the entire lifting operation with which they are assisting. However, a dogger must not be used to also perform the role of a ‘spotter’ when the crane is operating close to overhead powerlines.
A crane operator is reliant on instruction from the dogger from the time it is slung until it is securely placed in its final position and slings are removed. If a load is being controlled by more than one dogger, the different doggers must know what part of the lifting operation they are responsible for.
A qualified dogger is required to know how to:
- use the various types of ropes, slings, chains and accessories
- determine the SWLs of any rope, sling, or chain to be used for lifting
- assess the weight of loads to be lifted
- sling loads of different weights and sizes safely
- direct a crane or hoist operator in the movement of a load (this is particularly important when the load is out of the operator’s view)
- give appropriate hand and whistle signals used for directing loads
- control load movement through tag lines.
Qualified doggers are also required to have refresher training.
A reliable method of signalling between the crane operator and dogger and any other assisting workers is essential for safe crane operation. Failure to implement a reliable method of communication may lead to unsafe crane operation resulting in dropped loads or collisions.
An effective means of communication is particularly important where:
- the crane operator cannot see the load
- the crane operator cannot see the load's landing area
- the crane operator cannot see the travel path of the load, crane or part of the crane (slewing counterweight)
- the crane operator cannot see the dogger or other workers in the work area
- the crane operator is not in a position to make an accurate judgement of distance
- it is possible for the crane to come into contact with overhead powerlines.
The control measures put in place should be reviewed regularly to make sure they work as planned.
- How to manage work health and safety risks Code of Practice 2011 (PDF, 0.99 MB)
- Managing risks of plant in the workplace code of practice 2021 (PDF, 1.04 MB)
- Managing the work environment and facilities Code of Practice 2021 (PDF, 0.7 MB)
- Mobile crane Code of Practice 2006 (PDF, 1.34 MB)
- Mobile plant
- Dogger- DG
- Working in and around mobile plant – film
- Traffic Management: Guide for construction work - Safe Work Australia
Support for people affected by a serious workplace incident
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