As equipment optimization strategies evolve, consider steps that can improve your maintenance program, increase haul truck availability, and decrease costs.

by Craig Eller and Kevin Gildea, P.E.

With the ongoing advancements in maintenance technology, most industries are pursuing initiatives related to condition monitoring, which moves them away from the traditional time-based actions. The aggregates industry is no exception, and there are many opportunities to adopt more sophisticated, less invasive maintenance practices. The use of technological advancements, such as continuous fault monitoring and parameter trending on rigid frame haul trucks, improve truck performance and lower life-cycle costs. The use of new technology is most effective, for any machine, when a solid foundation of best practices is implemented. These best practices usually involve consistent inspections and carefully documented results. Most, if not all, maintenance programs can find areas to improve on these basics, while preparing for further evolutions in equipment optimization techniques.

Improve what you already do

There are many ways to monitor a system or component and accurately predict when it approaches the end of its service life. Some of these methods are simple, and most maintenance programs have been engaged in these practices for some time. However, it may be helpful to step back and ask if these simple steps are being done properly and are making the most of the available data.

An OEM’s haul truck maintenance manual may provide guidance to accurately assess steering linkage bushing wear.

In general, equipment maintenance programs include the following practices:

Oil Analysis. An oil program is only as good as the sample. With clear guidance, two common pitfalls can be avoided.

• If there is a sample line, effectively purge the residual oil before the sample is drawn.

• For mobile equipment, draw the oil before any particles settle.

In addition, there are system arrangement considerations that can significantly impact the accuracy of a sample. Consider the following:

• Are the samples’ locations oriented properly in relation to the filter?

• Does the arrangement allow the technician to obtain a sample without introducing contamination (oil runs down the side of a sump and into the bottle, etc.)?

An assessment chart allows haul truck maintenance crews to quickly determine whether or not a suspension is properly charged.

Pin and bushing wear assessment. Where possible, slop (or play) limitations in an axis of normal wear should be defined and easily measured. Much of this is established when the connections are designed, but a few simple measurements often can significantly improve the assessment capability.

Structure inspections. This most basic maintenance action becomes much more effective and efficient when guidance is provided on where and how to inspect (visual, non-destructive testing, etc.). Obviously, some areas of the structure are more critical and susceptible to cracking, while other areas experience low stress and do not require as careful an inspection. Additionally, to further improve the ability to monitor structural condition, cracking thresholds are necessary to explain what amount of cracking requires immediate repair and what can be scheduled for future planned down periods.

Collect basic data and use it

Based on the characteristics of the given equipment and operating environment, logical individual threshold values need to be clearly defined. When thresholds are exceeded, logical and realistic corrective action should be specifically explained.

This flowchart may be used to identify corrective action when a suspension is not properly charged.