Tough Equipment Battles Hard Rock
“That L350 is a beautiful loader,” says Jason Delaqua, equipment manager for LTL Contracting. “The operator loads a truck with three passes. The power of that machine is phenomenal.”
There’s a break in the action, and operator Mike Halstead steps out of the L350F wheel loader. “I like it a lot,” he says. “It’s very smooth, and has great power, once you learn how to run it. With a Volvo loader, you don’t just charge the pile at top speed. If you do that, you’ll spin the tires. You go in at low rpms, and lift, tilt, lift, tilt. I can load a 40-ton truck in three passes.”
LTL’s Volvo dealer representative, Gary LaFreniere of Strongco, explains that a Volvo loader is designed to produce maximum torque at low engine speeds. And the powertrain is designed to match that feature. “So once Mike learned to ease into the pile at low rpms and feel his way in – lift, tilt, lift, tilt – he became a much better operator,” says Gary. “More rpms does not always equal faster loading.”
Adds Kevin: “The Volvo loaders are very dependable. They’re strong, and they have quick cycle times. And they’re very comfortable. Fuel efficiency is very good for the size of the excavators and loaders that we run.”
Jason says he and other LTL managers are being trained on CareTrack, Volvo’s telematics system for reading out machine operating information at remote locations away from the machine. “That CareTrack system is great,” Jason says. “It actually sends me alarms on my cell phone if something is wrong. It’s got low fluid level sensors, overheating sensors, and it tells you idling times, running times, and a whole lot more. We need some time just to digest all that information.”
At the tailings dam site, the articulated trucks are dumping waste rock. Each year the mine comes out with an additional dam raise. LTL is now working about a 4-meter vertical lift. That will be a 16-meter-wide top, a roadway, when the raise is finished. On the downstream side, the dam needs a fill of about 50 meters wide. So just to get the width of the dam at the top, LTL adds more material at the bottom to widen the dam and give it a solid foundation.
“Once we have achieved that grade, then we place cushion material on the upstream side of the dam,” Kevin says. (Cushion material is rock crushed to 63-mils minus.)
At the dam site, a Volvo EC380D excavator is working at the toe of the dam, to excavate to bedrock. The EC380D casts dirt and excess waste rock away from the toe of the rock slope, to clear the way for more suitable material that slides down as the trucks dump it.
“We prefer the Volvo excavators because we have found that their fuel economy is excellent, and so is the strength of their hydraulic systems,” says Kevin. “And for comfort for the operators, and for efficiency, we prefer the Volvo products.”
As the EC380D excavator works, Jason explains that the bucket has been hard-faced with T-400 steel on the underside, to better resist wear from the abrasive rock. Meanwhile a Volvo EC480D also works to excavate dirt from the toe of the downstream dam slope.
Wear and tear caused by the abrasive rock is a primary challenge faced by LTL Contracting. “The biggest thing is that it is rock,” Scott says. “We’re not moving gravel. We’re moving anywhere from 7,000 to 12,000 cubic meters of material a day. So when you start putting that in and out of truck boxes and loader buckets, you get a lot of wear, just because of the sheer volume and hardness. We line the boxes and hard-face the buckets. And we check tire pressures weekly.”
Moving down the dam about 200 feet, a Volvo A30D dumps a load of waste rock over the edge of the dam raise. “We like the Volvo articulated trucks because of their power, speed, and comfort,” says Kevin. “The operators have zero fatigue at the end of a 12-hour day.”
Kevin is impressed with the low maintenance requirements of Volvo equipment. “On a 24-hour cycle, which we have run, or even the 12-hour cycle that we’re running in now, the maintenance is nearly zero,” he says. “We currently do 250-hour services on all the Volvo products even though they give you a 500-hour cycle.”
The main management challenge at the mine is to organize haul routes and schedule the rock hauling for maximum productivity, Kevin says. And safety is a very big aspect of mine life.
For example, the mine posts speed limits of the articulated trucks at 40 kilometers per hour on haul roads, and 20 km/hour near buildings. “Currently, our cycle time with the Volvo A40F haulers is approximately 12 minutes,” says Kevin. “That’s loaded, dumped, run to the tailings management facility, and returned. The approximate speed that we’re running is an average of 35 kilometers per hour. The Volvo haulers will run about 60 kilometers per hour, and that is a very comfortable speed, but the mine has restricted speeds to 40.”
Kevin says LTL has tried competitive trucks, and has found that the Volvo articulated trucks “far exceed the performance of the competitor’s equipment. For fatigue at the end of the day, for reliability, and maintenance, we have found that we prefer, and will continue to prefer, the Volvo A40F rock trucks.”