Defensive Drills

When it comes to keeping your drill in top shape, think beyond the basics of blocking and tackling.

By Christian Blunck

Experience seems to point out that, for many operations, blasthole drills may end up at the bottom of the game plan when arranging for maintenance. While perhaps not as visible as wheel loaders and haul trucks, day in and day out, drills are equally important parts of your equipment fleet.

Keeping the cabin door closed as much as possible helps keep filters and the inside of the cab clean, and eases the load on the climate control.

Proper drill maintenance helps ensure machines are ready for operation when it’s time to drill. It’s also critical to getting the most work from the asset with the least amount of cost over its life span.

Drill manufacturers today recommend a planned approach to drill maintenance that starts with the day you take delivery and extends throughout the life of the machine. According to Avery Martin, product line manager with Sandvik Mining and Construction, “We have a lot of data that demonstrates the importance of preventive maintenance in keeping machine availability high, as well as optimizing the lifetime cost of the drill.”

One of the easiest actions to take on your drill is to simply follow the maintenance schedule provided by the manufacturer. This typically includes inspections and service every 250 hours. Oftentimes, a simple scheduled service inspection can eliminate — or at least minimize — unnecessary downtime. Changing fluids and filters as recommended by the manufacturer is the primary and least expensive step to minimizing costly downtime. Following the maintenance schedule and avoiding shortcuts in the steps are key. Keep in mind that these intervals, recommendations, and inspection steps have been developed through each manufacturer’s long history of supporting blasthole drills.

Using OEM replacement parts and components in preventive maintenance replacements, as well as repairs, is another important consideration. With the heavy-duty cycles that today’s precision drills undergo, trying to save a little with alternate parts suppliers can bring additional headaches, as wear cycles are less predictable and sub-par parts, materials, and designs can end up creating even bigger problems.

Winning strategies

In addition to the areas covered by manufacturer maintenance schedules, here are several drill components that do not always receive the appropriate level of attention.

Daily inspections, level checks, and observation of all systems can help ward off unnecessary repairs and downtime.

Drifters: Drifters are the most obvious example. Experience clearly shows that the drifter is one of the hardest working components on a drill. Accumulators on the drifter oftentimes go unchecked. The result: accumulators (especially on the low side) go flat or fail, resulting in hose failures on the return line back to the tank. Manufacturers recommend checking accumulators at least once a week to ensure they are holding the proper nitrogen charge. “While such checks may take 20 minutes a week, it’s a good investment,” Martin says.

Cooling systems: Radiators and coolers are important to the life of many key drill components and systems. Keeping them clean will extend the life of the components, as well as the life of coolants and oils. Checking them daily and cleaning them at least once a week will avoid downtime and help keep drills more productive.

Take wind direction into consideration to help avoid faster buildup of dust and debris back into the cooler’s screens and fins. When you set up on the bench, be sure to orient the machine so that the wind is carrying any fugitive dust away from the drill’s cooler intakes to help ensure non-stop, efficient drilling.

Compressors: You should always operate your air ends with recommended oils for the ambient temperatures in which you expect to operate. More often than not, when an air end is overheating, an improper grade of oil has been used. In addition, be sure that your thermostat is working properly and that you regularly change oil filters and separators as recommended by the manufacturer. You should also take diagnostic oil samples regularly so that, if bearings are starting to wear, you have an early indication and can avoid a catastrophic failure that causes further damage.

Drill manufacturers offer technical service training for new technicians and for current technicians wanting to hone their skills.