HEAVY EQUIPMENT MAINTENANCE MEANS FOCUSING ON FLUIDS
By Harold Hough  

If you have every gone to an auto parts supply store, you know that automobile fluids have evolved dramatically.  It’s no longer enough to grab a can of oil or automatic transmission fluid.  Model, mileage, and usage have a major impact on the type of fluids you use in your car.  And, don’t forget the filters that keep your fluids clean.  The same is true for your heavy equipment too. 

A piece of modern mining heavy equipment is a high performance thoroughbred.  It may appear to be a tough brute that appears impervious to dust and dirt, but if even a bit of invisible dust gets into the equipment’s fluids, you will be experiencing reduced performance, higher maintenance costs, and shorter lives.

In order to shoehorn the high performance into smaller packages, heavy equipment engineers have been forced to maximize several systems like hydraulics and the fuel system.  This requires higher pressures like 6,000 psi in hydraulics and 40,000 psi in fuel systems.  These require new, high technology fluids.  These fluids, in turn, require tighter equipment tolerances, which means smaller particles of dirt and dust, which didn’t bother equipment before, now can cause considerable problems.  In fact, a 5 micron particle can damage modern heavy equipment (a human hair is 80 microns in diameter).

Just to give you an idea of the danger, a hydraulic fluid once rated “clean” had an ISO rating 21/17.  That meant a one millimeter sample has about 2,000,000 particles 5 microns or larger and 130,000 particles 14 microns or larger.  Today, that rating is now considered “dirty” because hydraulic pumps operating at 32 gallons per minute, 8 hours a day, 200 days per year are pushing more than 625 pounds of dirt through the hydraulic system annually. ISO 18/15 (which is still rated “dirty”), will reduce the amount of dirt in your system to about 80 pounds per year.  A clean hydraulic fluid like 16/13 will reduce the annual amount of dirt to 20 pounds.

Putting lower grade hydraulic fluid into you heavy equipment won’t cause the equipment to immediately break down.  However, it will start to reduce efficiency.  As these particles build up on metal surfaces and impede hydraulic flow, system efficiency erodes. But even a skilled operator may not notice a drop in responsiveness until the system has lost nearly 20% of its power.  The result is that your expensive piece of new heavy equipment will be no more efficient than the old equipment you replaced.  And, your hydraulic components may have their life reduced by as much as 90%

CONTROLLING CONTAMINATION

There are ways you can reduce your contamination problem.  The first is to repair oil leaks immediately.  If oil can get out, dirt can get in, especially during operations in the mine, where dust and dirt are constantly flying through the air.  The same goes with oil seals.  A bad oil seal is an ideal entry point for dirt.

A clean maintenance shop also helps dramatically with controlling contamination because less dirt will end up inside components that are undergoing repair.  And, a clean floor will make it that much easier to discover fluid leaks when they occur.

Part storage is also critical.  Filters shouldn’t be opened before they are ready to be installed because they will accumulate dirt otherwise.  The same applies to components.  You may be tempted to take that hydraulic component out if its sealed plastic bag when you get it, but that makes it vulnerable to contamination.  Even if you put it back into the bag and then replace it in the box, it will still be contaminated by the particles of paper found inside the box.  And, anyone working in a dusty environment knows how dust can get everywhere, even inside boxes.

Finally, the most important part of any contamination control program is training of employees.  In many cases, the biggest problem may be with the older mechanics, who don’t realize that new equipment is less forgiving of maintenance practices of just a few years ago. 

In the last few years, hundreds of mines have invested in new heavy equipment.  However, that investment relies to a large degree on keeping its fluids cleaner than we ever did before.  Contamination control will keep that equipment working better and lasting longer.