Savings with onboard weighing systems

An on-going study between the University of Auckland and Actronic Technologies illustrates huge savings in fuel, equipment and labour costs per tonne of material moved by using Loadrite onboard electronic weighing systems to optimise truck loading. 

The study found that a New Zealand quarry loading 1600 road trucks per week could save 800 hours of staff time, 800 hours of equipment time and 7800 litres of diesel each year by using weighing systems onboard its wheel loaders.

Onboard weighing systems assist loader operators to accurately fill trucks to their rated capacity. This improves efficiency by reducing the number of trucks that must tip off excess material or be topped up; reduces the average time a truck spends on-site; and reduces the number of trucks leaving the site underweight or overweight – minimising both the number of truck trips and overload fines.

Informal estimates suggest that when a wheel loader operator loads a truck by eye, roughly 10 percent will be significantly over or under-loaded and will need to be adjusted, says the study. This compares to less than two percent of all trucks in the case study quarry where Loadrite weighing systems were used onboard Caterpillar 980-G and 980-H wheel loaders.

Of the 83200 trucks loaded each year by the quarry’s four wheel loaders, an estimated 8320 trucks would need to have their payload adjusted if onboard weighing systems were not used, says the study.

It was found that trucks that are overloaded typically tip off excess material in waste piles near the weighbridge, while trucks that are under-loaded are typically topped up near the weighbridge by a wheel loader that drives down from one of the main stockpiles.

By using Loadrite weighing systems onboard its wheel loaders, the study estimates that the quarry will only need to make 1560 truck adjustments in any given year. Reducing the number of truck load adjustments by 6760 saves the quarry and its customers over 800 hours of staff time, 800 hours of equipment time and 7800 litres of diesel each year. And for each litre of diesel saved, the quarry also reduces its carbon dioxide emissions by 2.68 kg (www.epa.gov/stateply).

For simplicity, the calculations do not include a return trip for the wheel loaders as they sometimes move onto other tasks near the weighbridge. The calculations also assume that no unnecessary truck trips are made from quarry to job site. In practice, however, it is likely that wheel loader operators will try to under-load trucks slightly when loading by eye. This is because an overloaded truck can be fined, whereas an under-loaded truck cannot.

As such, the results are likely to underestimate the full fuel and time savings. Take a fleet of trucks that can each carry 26 tonnes as an example. If each truck was under-loaded by an average of one tonne, it would take 26 trips to move the same amount of material that could be moved in 25 trips if the trucks were correctly loaded.

If you are interested in finding out the savings a Loadrite weighing system can bring to your site, contact Jeff Vickers, a PhD fellow in the Department of Civil and Environmental Engineering at the University of Auckland. Selected sites will also receive a no obligation trial of a Loadrite weighing system. You can contact him by phone, 09 820 7720 ext. 796, or email jeff.vickers@actronictechnologies.com.