Unloading a dump truck can be a hazardous operation, particularly when the ground is uneven or when the load is being delivered into a pit. This is a common scenario at mining sites. Moreover, dump trucks loaded with coal can face even higher risks because the load can be wet, freeze in the bed, and stick in the bed. When the bed is raised, a frozen load can cause the truck to tip and even roll over. These hazards and ways to mitigate them were outlined in a Safety Alert from the Safety and Health Administration . Employers at coal mines, construction sites, highway projects, and any other venues where dumping occurs should regularly review their safety procedures; and with winter approaching, now is a good time to provide drivers with instructions and training on avoiding frozen loads and implementing enhanced safety procedures if loads are frozen.
In its alert, incident where a driver of a tractor trailer coal truck died when his truck tipped over as he was attempting to dump a load of coal that was frozen. As the bed was raised, the trailer rocked and eventually tipped over. The driver made the error of jumping from the cab as the truck was moving. He was struck by the truck and was fatally injured.
“A raised truck bed can easily overturn due to its size and weight,” . “Uneven ground, unbalanced load, and/or underinflated work tires increase the hazards associated with this task. These hazards can be avoided with proper training and implementation of best practices.”
Recently at one of our active Construction sites, one incident happened where a dump truck toppled while unloading material from its bed. As everyone working near maintained a safe distance, no injury resulted. Upon investigation, it was found that improper ground conditions and poor judgment of the operator led to the instability of the truck and resulted in toppling.
A Dumper truck is a truck used for transporting and carry loose material such as sand, gravel, or dirt. A typical dumper truck is equipped with an open-box bed, with a hinged rear gate and is equipped with hydraulic pistons to lift the front, allowing the material in the bed to be deposited (dumped) on the ground behind the truck at the delivery site.
One of the major hazards related to the use of dump/tipper trucks is tip-over.
This hazard majorly arises when the truck box is in the raised position and when the center of gravity of the box and load is not roughly between the frame rails of the unit.
It is recommends that drivers:
- Keep tires properly inflated and ensure they are not worn.
- Use antifreeze in cold weather to prevent material from freezing and sticking in the truck bed. Ensure the load is evenly distributed.
- Never overload the upper portion of the truck bed.
- Keep your truck and trailer in a straight line when backing up, and never move faster than walking speed.
- Stay in the cab with your seat belt on during the entire dumping process. Never attempt to exit or jump from an overturning truck. Remaining in the truck is the single best thing drivers can do to protect themselves at a mine.
- Dump only on level surfaces, and never dump when surfaces are uneven, loose, or not properly compacted.
- Mount a thermometer at the dump site to inform truck drivers of freezing conditions.
- Adhere to MSHA’s requirement at 30 CFR 77.1708 to “establish and maintain a program of instruction with respect to the safety regulations and procedures to be followed at the mine and shall publish and distribute to each employee, and post in conspicuous places throughout the mine, all such safety regulations and procedures established in accordance with the provisions of this section.” This regulation encompasses the operation of dump trucks at mine sites.
One or more of the following factors can adversely affect stability:
- The truck is not on a level surface when dumping.
- A large amount of materials is in the upper position of the raised box.
- The rear wheels settle unevenly as the load moves to the rear while dumping.
- Poor rear suspension systems on one side of the dump truck.
- Uneven tire pressures in rear wheels.
- Worn or inadequate components of the lifting system such as pins, lifting cylinders.
Safety Guidelnes to be followed while using Dump /tipper Trucks include:
- Review and understand the information provided in the dump truck operator’s manual with particular attention given to descriptions of safety procedures.
- Inspect the dumper truck/dump truck, including the head and tail lights, horn, rear view mirrors, tires, air brakes, and fluid levels and also maintained manufacture daily checklist.
- Check tire pressures daily. Tire pressures should be equal on each side of the vehicle, according to manufacturers’ recommendations.
- If any dump truck equipment fails the pre-use inspection, the equipment has to be returned back to the owner to make necessary repairs.
- During entering or exiting the cab of a dump truck, always use the handhold and steps.
- Know the locations of obstacles such as boulders, overhead electric lines, fences, and low tree limbs in areas where loading, hauling, and dumping will occur.
- Be aware of blind spots when reversing a dumper truck. Carefully adjust rear view mirrors to maximize you’re of view area. Always use a “spotter/signal person” when backing a dump truck.
- Know where other workmen are located in the loading, hauling, and dumping areas.
- Engage the dumper-box lock bars before performing maintenance or other jobs under a raised dumper box.
- Recognize surface areas hazardous to dumpings, such as uneven and sloping surfaces or poorly compacted fill. Dumping loads during located on hazardous location, areas may result in vehicle tip-overs.
- Ensure length of travel is reasonably level and compacted before spreading material by dumping from a moving truck.
- Dumper trucks should not dump any material when they are parked side by side with another vehicle. When a dump truck tips over, it is often the operator in the adjoining vehicle that is injured.
- Obey all traffic rules and speed limits that are applicable to project/site roads.
- Don’t work under a raised box (not even “for just a little bit”) unless the box is adequately supported by a prop rod or cribbing. Do not rely on the truck’s hydraulic system to hold the box up while working under it.
Be aware of the hazards and risks while using the Dump/Tipper Truck. Ensure adequate safety measures before and during job execution are fulfilled. Your constant vigilance, timely and prompt actions could eliminate major incidents.