"If it ain't broke, don’t fix it" is a common-sense approach to maintenance and life in general. Keeping your company's guided boring machine (GBM) in good working order with a solid preventative maintenance program means your GBM working, rather than sitting in repair shops. Such a program takes a two-pronged approach, addressing everything from a simple visual inspection to more complex procedures for proper storage, to keep your equipment profitable instead of broken.

Basic Guided Boring Machine Maintenance

A visual inspection of the GBM, such as giving the machine a simple once-over, whether before being dispatched to a job or just in passing, can spot some problems before they become problems on the job. Take note of what fails most often or what needs to be replaced regularly.

Your accountant or purchasing manager can tell you which GBM parts are ordered most often. Your list will likely include O-rings and filters, but you should also include the small things that can be replaced in the field: an hour lost to a successful repair is better than a job lost completely. (Also read, "Proper Maintenance for Drill Rig Equipment.")

Make a List of Inventory and Frequent Issues

Make up a kit that contains the parts that can (a) fail often and (b) can be replaced in the field and put it (along with an inventory-style list of the parts) in the power pack of every GBM. Make a start-up checklist for each GBM and remind your operators to pay close attention the following before they begin working with the machine:

Inspect the GBM Often

Visually inspect each major assembly. If you spot something before the GBM goes into the field, is just back from the field, or when it's waiting for a job, do something about it. Make simple repairs as soon as needed or as soon as possible.

Fluid Levels

Keep all fluid levels on the equipment full. Check them before leaving for a job and after.

Maintain the Paint

Keep the GBM's paint job looking good. That thin skin of paint is all that protects the GBM's metal. Repainting small areas that require it can help avoid a complete (and expensive) paint job.

Above all, stick to the maintenance instructions in your GBM's maintenance manuals. (Learn more in "How Tunnel Boring Machines Work.")

Advanced Guided Boring Machine Maintenance

Your GBM operators are professionals. They know what to do before they launch, but there are still things that they should do as part of a proper maintenance program for your guided boring equipment.

The first item is to bring all fluid levels (hydraulic and lubricant) in the GBM up to the "full" level. Use the GBM manufacturer's recommended products. Not doing so can lead to damage to the equipment. Another problem this helps avoid is one of safety: equipment that isn't operating properly is unsafe. (Read on in "Trenchless Operations Safety Do’s and Don’ts.")

After they've checked the oil levels, they should test each of the major assemblies of the GBM. This not only ensures that each component works but also gives them a second chance at a visual inspection.

A quick look at the pilot tube, the steering head and the rest of the machine may make the difference between a successful bore and a project that grinds to a halt halfway through a job. If they need to replace O-rings or filters, now's the time.

Additionally, they should perform a visual inspection of the GBM's accessories. An auger or cutting head with issues can cause serious downtime.

Ensure the emergency-stop control works as it should. If it – or any other control or gauge – does not work properly, it should be replaced.

GBM Maintenance After a Job

When the job's done and the GBM returns to the office, it's not quite ready to go into storage until it's needed again. Instead, the preventative maintenance continues. The first matter is the pilot tube:

  • inspect and wash drilling mud and other debris from the inside and outside of the pilot tube before it can turn into something resembling concrete.
  • Dry the pilot tube and inspect the pilot tube's threads. Treat the threads with an anti-seize lubricant and replace O-rings as needed.
  • Check the theodolite's accuracy. Ensure the theodolite and other instrumentation is clean and dry and returned to their cases.
  • Disconnect the hoses that connect the jacking frame and power pack. Replace the hose caps/plugs and store the hoses in the power pack.
  • Retract hydraulic cylinders.
  • Clean debris and dirt from the casing, the augers, and the cutting head.

A clean, well-maintained GBM is a happy GBM. It also means happy customers.