The Overdue Haul Road Inspection
It is 06:40 on a wet winter morning. You are the quarry supervisor and the only competent person on site until the day-shift fitter arrives at 07:30. The 22-tonne dump truck has been parked overnight at the top of the main haul road. The pre-start walkaround reveals: nearside front tyre with a 12 mm sidewall bulge and a visible cord patch; the park brake holds on the 1-in-9 gradient but the service brake pedal travels further than the 40 mm free-play limit in the manual; the reversing alarm sounds intermittently when the ignition is jiggled. The driver is eager to start because the primary crusher is due to run dry by 08:00. Rain has been falling for six hours and the haul road's drainage channel is blocked, leaving standing water on the lower bend.
1. Decide whether the truck can be operated this morning, and justify your decision against the defects found.
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Do not operate. Each defect independently justifies taking the machine out of service:
- Tyre bulge with exposed cord: a structural sidewall failure. A 22-tonne loaded truck on a wet 1-in-9 gradient places enormous lateral and torsional load on that tyre; a blowout at speed is a foreseeable fatality. Defect is a fail under any pre-start regime.
- Brake pedal travel beyond the manual limit: the service brake is the primary stopping system. Excess travel indicates air in the system, worn linings or a leaking circuit. On a gradient with standing water, stopping distance is already compromised. Fail.
- Intermittent reversing alarm with an ignition fault: the alarm is a pedestrian-protection device. Intermittency suggests a loose connection that could also affect other circuits. Fail until rectified.
The correct action is to lock out/tag out the machine, record the defects on the pre-start sheet, inform the fitter, and arrange alternative feed to the crusher (stockpile reclaim by loader, or a short production pause). Production pressure never overrides a defect that could kill someone. The supervisor's duty is to make the safe choice easy to defend on paper.
2. The site manager pressures you to run the truck 'just for two hours' to keep the crusher fed. Outline your response and the controls you would put in place if any operation were permitted.
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Refuse the instruction and escalate. The law and good practice place the duty on the person in control of the workplace; a supervisor who authorises use of a machine with known brake and tyre defects is personally exposed, and so is the manager who instructed it. My response:
- State the specific hazards - brake failure on a wet gradient, tyre blowout under load, pedestrian struck by an unalarmed reversing truck.
- Record the refusal in writing (email or site diary) with time, defects and the instruction received.
- Offer the safe alternative - loader reclaim from stockpile, or a planned 90-minute crusher stop.
- Escalate to the site's health and safety adviser or the quarry manager above the site manager.
If a manager still insisted, I would not operate the machine and would report it under the site's hazard-reporting procedure. There is no lawful 'just for two hours' exemption from a brake defect. The only permissible movement would be a low-speed recovery by a competent fitter with the machine isolated and a banksman, and even that should be risk-assessed first.
3. Separately, describe how the blocked drainage and standing water change your traffic management plan for the morning.
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Standing water on a bend changes grip, braking distance and visibility from spray. Controls:
- Reduce speed limit on the affected section (e.g. from 20 km/h to 10 km/h) and brief all drivers at the pre-start meeting.
- Clear the drain before heavy traffic resumes, or cone off the flooded bend and reroute if an alternative exists.
- Increase separation between machines; a loaded truck needs far more distance to stop on wet ground with a marginal brake.
- Restrict the lower bend to one-way traffic with a banksman or radio control until water is cleared.
- Re-brief pedestrians on the changed route and reinforce the rule that no one walks the haul road.
Document the changes on the traffic management plan and brief sheet so the decision is auditable.