High Risk Work Licence - Slewing Mobile Crane C6 (60t) cheat sheet

A C6 slewing mobile crane licence authorises operation of slewing mobile cranes with a rated capacity above 20 tonnes up to and including 60 tonnes; it does not cover non-slewing or larger classes.

Primary duty holders: the person conducting a business or undertaking (PCBU) holds the primary duty of care; officers must exercise due diligence; workers must take reasonable care of themselves and others and follow reasonable instructions.

High risk work licensing sits within the model WHS Regulations: the operator must hold the correct licence class and must be able to produce it on request; operating without it is an offence.

A safe work method statement (SWMS) is required for construction work classed as high risk, including crane work near energised electrical installations, on or near roads, and involving tilt-up or precast concrete.

Key standards to cite: AS 2550.1 (general cranes), AS 2550.5 (mobile cranes), AS 1418 series (crane design), AS 3775/AS 1353 for slings, and the rigging and dogging guidance in the WHS framework.

Design registrations and major inspections: cranes and certain items (e.g. some lifting gear) require design or item registration and periodic major inspections at intervals set by the regulator, commonly 10 years for cranes.

Competency is role-specific: doggers, riggers, crane operators, spotters and safety observers each need the competency or licence for their task; a licensed operator is not automatically a licensed rigger.

Records that must be kept include logbooks, maintenance and inspection records, lift plans, SWMS, training and licence evidence, and load test or verification certificates.

Risk assessment formula: risk = consequence severity x likelihood; controls follow the hierarchy - eliminate, substitute, engineering, administrative, then PPE as the last line.

Common mobile crane hazards: crane overturn, boom or structural failure, load drop, crush between load and structure, contact with powerlines, ground collapse under outriggers, and personnel struck by the slewing tail radius.

The tail swing (counterweight radius) creates a crush zone behind the slew ring; persons must be excluded from the full swept area, not just the load path.

Dynamic factors increase effective load: wind, centrifugal effects from slewing, snatch or shock loading, and rapid hoist or brake application; these reduce available capacity.

Wind limits are crane- and load-specific: load chart or manufacturer data sets the maximum; large sail-area loads need a lower limit because wind force rises with the square of wind speed.

Two-blocking, hook over-hoist and boom over-load are managed by limiters and indicators; these devices are controls, not substitutes for the operator's judgement and must be tested pre-start.

A hazard is any potential source of harm; a risk is the combination of likelihood and consequence of that harm occurring; a control is any measure that removes or reduces the risk.

Residual risk must be recorded and accepted by the responsible person; if residual risk is not tolerable, the lift must be re-planned or stopped.

Rated capacity equals the lowest of structural capacity, stability (tipping) capacity, and any configuration limit; the load chart value is the maximum gross or net capacity per the chart's stated basis.

Net capacity = rated capacity minus the weight of all lifting attachments below the hook (hook block, slings, spreader beams, shackles); gross load includes the load plus rigging.

Capacity falls as radius increases and as boom length increases; the chart is read at the actual working radius measured from the slew centre to the load's centre of gravity, not to the boom tip.

Configuration variables that change the chart: boom length, boom angle, jib fitted or stowed, counterweight configuration, outrigger span (fully extended, mid, or retracted), and pick-and-carry mode.

Pick-and-carry charts are separate and much lower than static charts; travelling with a load requires a level, prepared route, correct tyre pressure, and manufacturer-approved travel configuration.

Duty or utilisation: some charts are marked for stationary or for travel use; never interpolate between chart columns or radii - use the column for the next greater radius and the shorter boom.

A load moment indicator (LMI) or rated capacity limiter warns and then cuts out functions at the set limit; the operator must know the cut-out settings and never override them.

Auxiliary or runner rigging, fly jibs and luffing jibs each have their own capacity derating; check the specific chart page for the exact boom/jib combination fitted.

Sling tension in a two-leg sling: tension per leg = (load / number of legs) / cos(angle from vertical); as the angle from vertical increases, leg tension rises sharply.

Sling angle factor: at 30 degrees from vertical each leg carries about 1.15 times its share; at 45 degrees about 1.41; at 60 degrees about 2.0; never exceed the sling's rated angle.

Working load limit (WLL) of a sling is its marked capacity for the configuration used; a choke hitch derates capacity (commonly to about 80 percent of the vertical rating), and basket and multi-leg configurations change the effective WLL.

Load estimation: steel mass approximately 7850 kg per cubic metre; concrete approximately 2400 kg per cubic metre; water 1000 kg per cubic metre; timber varies by species and moisture.

Centre of gravity must be below or aligned with the hook; an off-centre CoG causes load tilt, unequal leg loading, and possible load slip or crane side load.

Tag lines control rotation but must not be used to drag or side-load a load; side loading of the boom or hook is a structural hazard and is outside the load chart.

Inspection before use: slings and shackles must be checked for cuts, broken wires, corrosion, stretched or deformed hardware, illegible tags, and missing safety latches; defective gear is tagged out and removed from service.

Shackle and hook rules: the load must sit in the bowl of the hook, the hook latch must be closed, and shackle pins must be fully engaged and moused where required.

Ground bearing pressure under an outrigger = load carried by that outrigger divided by the effective pad area; increase pad area (spreader pads, mats, steel plates) to reduce pressure on the soil.

Outrigger loads are not equal: the load-side outriggers carry far more than the rear or offside ones, and the maximum outrigger load usually occurs with the boom over that corner at maximum radius.

Ground must be assessed for bearing capacity, voids, buried services, backfilled trenches, cellar covers, and slope; competent geotechnical advice is required where capacity is uncertain.

Outriggers must be fully extended and set per the manufacturer's configuration; partially extended outriggers change the load chart and must be matched to the correct chart.

Pads must be level and in full contact; the outrigger float must sit centred on the pad, and the pad must be large enough to prevent punching shear or edge failure.

Exclusion zones: barricade the slew area, the tail swing, the outrigger footprint, and the load path; the crane must be set up on stable, drained, level ground clear of excavations and their zone of influence.

Clearances to be verified at set-up: powerlines, buildings, other cranes, public roads, and the full boom and jib envelope through the planned slewing arc.

After set-up and before each lift, re-check level (bubble or inclinometer), outrigger penetration, pad stability, and that no outrigger has lifted or settled.

Pre-start checks cover: fluids and leaks, tyres and pressures, brakes, steering, outrigger beams and floats, wire rope (broken wires, kinks, corrosion, end terminations), sheaves, hook and latch, boom pins and wear pads.

Safety devices to be function-tested: rated capacity limiter or LMI, boom angle and length sensors, anti-two-block, hoist limit, outrigger position sensors, level indicator, and audible alarms.

Wire rope discard criteria include the number of broken wires in a lay length or over a set length, reduction in diameter, and broken strands at terminations; follow AS 2759/AS 3569 and manufacturer data.

Defects are classified: a defect affecting safe operation means the crane is tagged out, isolated, and removed from service until repaired and re-verified by a competent person.

Logbook entries must record the inspection date, findings, and actions; the logbook travels with the crane and is evidence of the maintenance regime.

Maintenance intervals follow the manufacturer's schedule and the applicable standard; major inspections and load testing are separate from routine servicing.

Any incident, near miss, or load-dropping event triggers an inspection before the crane returns to service; the operator must report, not self-clear, structural damage.

A lift plan documents: load weight and CoG, rigging arrangement, crane position and configuration, radii and boom lengths, capacity utilisation, ground conditions, exclusion zones, personnel roles, and contingency.

Capacity utilisation is the planned load divided by the chart capacity at the working radius; a common planning threshold is 75 percent, above which a more detailed plan and engineering review are warranted.

Multi-crane lifts: the load must be shared by load cells or calculated sharing; each crane's chart must be met for its share, the load must be kept level, and a single nominated person must direct the lift.

Multi-crane lift rules: no crane may be loaded beyond its chart, the load must be free to move without inducing unknown forces, and the lift must be planned for the loss of one crane where practicable.

Blind or complex lifts need a nominated dogger or rigger in communication with the operator, a defined landing point, and a trial lift to verify stability and rigging before the full lift.

Load path and landing: verify the destination can take the load, that the load is clear of obstructions throughout the slew, and that the landing area is prepared and barricaded.

Trial lift: lift a few centimetres, stop, check rigging, load stability, brake holding, crane level, and outrigger behaviour before continuing.

Environmental limits: cease lifting when wind, visibility, lightning, or ground conditions exceed the plan's stated limits; the plan must state these limits in advance.

Standard hand signals are the primary communication method; only one nominated person gives signals to the operator at a time, and the operator obeys that person only.

A stop signal may be given by anyone on site; the operator must stop immediately on a stop signal regardless of who gives it.

Radio communication requires agreed channel, call signs, and clear confirmation; the operator repeats the instruction before acting, and radio failure means the lift stops.

The operator must maintain continuous contact with the dogger/rigger; if line of sight is lost, a relay spotter or radio is required and the lift must not proceed blind.

Signals must be distinct and unambiguous: hoist up/down, slew left/right, boom up/down, extend/retract, stop, and emergency stop each have a defined hand signal.

Personnel coordination: define the roles of operator, dogger, rigger, safety observer and spotter before the lift; the spotter's sole task is observing the crane envelope and exclusion zone.

Emergency stop signal and the means to give it must be known by all personnel; the operator must be able to stop all motion instantly and the area must be clear before restarting.

Approach distances to overhead powerlines are set by the regulator and the electricity network; the minimum is commonly 3 m for low voltage and greater for higher voltages, with the exact figures taken from the applicable state or territory rules.

Where the required clearance cannot be maintained, the line must be de-energised and isolated under a permit, or the crane must be fitted with a validated height-limiting or proximity device.

The spotter's role near powerlines is to observe the full boom, jib, rope and load envelope and call stop before any part enters the exclusion zone.

If contact occurs: the operator should remain in the cab if safe, warn others away, and not allow anyone to touch the crane; evacuation is by jumping clear with feet together if the cab is unsafe.

Exclusion zones must also be set for the load path, the slew and tail swing, and the outrigger footprint; barricades and signage must be maintained for the duration of the lift.

Environmental hazards: wind speed and gusts, heat and cold affecting personnel and hydraulic performance, poor lighting, rain and lightning, dust, and noise affecting communication.

Cease work and secure the crane when lightning is within the plan's stated radius, when wind exceeds the chart or plan limit, or when visibility prevents safe communication.

Shutdown sequence: land and secure the load, retract the boom to the travel position, stow the jib, retract outriggers fully, set the park brake, and lower attachments per the manufacturer's travel instructions.

Secure the crane: park on level ground, apply the park brake, chock wheels where required, isolate the battery or master switch, lock the cab, and remove the key to prevent unauthorised use.

Travel configuration: boom stowed in its cradle, jib secured, outriggers fully retracted and pinned, and any counterweight or attachment removed or secured as the manufacturer specifies.

Transport: verify axle loads and gross mass against the permit and the vehicle's ratings, secure the crane to the float with rated chains or straps, and check height and width clearances on the route.

Emergency procedures: know the location of fire extinguishers, first aid, emergency stop, and the site emergency assembly point; the lift plan must state the emergency response for load drop, contact with services, and crane overturn.

Load drop or rigging failure: stop, keep personnel clear, do not re-enter the drop zone, isolate the area, and report to the supervisor before recovery.

After any emergency or unplanned event, the crane is inspected by a competent person and defects are recorded before returning to service.