Equipment Management


August 1, 2011

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.

Heating/air conditioning: The air conditioner on a drill can be one of the most important systems for keeping the drill productive. Martin recommends regular service including changing filters, maintaining the R134a refrigerant, and regularly checking belt condition and tension.

Keeping the cabin door shut is the simplest and most cost-effective way to ensure a comfortable operator and also help the system remain in good operating condition. When working with customers on the job site, Martin often observes operators exiting the cabin and leaving the door open with the air conditioning running. Doing so means the cabin has lost all of the cold air, plus it causes an infiltration of fugitive dust. The result? The air conditioning unit operates at partial efficiency, works harder than needed, and could possibly encounter premature failure.

Position the drill on the pattern so that dust and debris are blown away from cooling system input screens for optimum, non-stop operation.

When setting up on your next drill hole, try to keep the sun to the back of the drill to assist with cooling. This will not only improve cooling, but also remove the glare of looking into or in the direction of the sun, which can reduce operator strain and increase safety.

In many conditions, a light tint on cabin windows can improve cooling efficiency by up to 30 percent.

Going for the extra point

For operations interested in a higher level of maintenance, some manufacturers offer additional programs aimed at keeping drills working at optimum efficiency. Training programs are available for service technicians and drillers to hone skills related to periodic maintenance of their operation’s drill fleet. Additionally, drill manufacturers extend their internal expertise and maintenance data to customers to help optimize drill maintenance and performance.

For example, Sandvik offers customers the Audit/Train/Troubleshoot (ATT) program. With ATT, a factory technician conducts scheduled audits of one or more drills and provides a customized list of recommendations that might include specific repairs, planned component replacement schedules, standard maintenance schedule adjustments, and possible customized training for the customer’s drillers or maintenance team.

Sandvik also offers a Remote Asset Management (RAM) program. With RAM, customers submit weekly reports of accumulated operation hours or accumulated production (drilled meters). The RAM planners then enter the data into a computerized maintenance database and send customers a report that forecasts maintenance requirements (based on part and component history life-cycles under corresponding application). Specifically, the report projects parts, materials, and labor, as well as a recommended schedule for suggested preventive maintenance work.

In addition to regular audits, oil sampling analysis from major drill components can verify wear characteristics according to the predicted change-out intervals.

Work a plan

While drill maintenance may not be at the top of your daily strategy, it is clearly worthy of a well thought-out game plan. Working that game plan will help operators control drilling costs and meet their drilling goals. AM

Christian Blunck is vice president of marketing for Sandvik’s U.S. and Canadian region.

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