Cover Story: 70-Metric-ton muscle

On the Pioneer Meadows multi-use site development project just outside Reno, Nevada, a prototype 70-metric-ton Volvo EC700B LC excavator has been loading 40-metric-ton artics with three passes, averaging less than a minute per load. The 1-million-cubic-yards-of-dirt excavation job is the North American testing ground for Volvo’s initial foray into this class of machine. And it’s gotten a lot of attention.

First the excavator took center stage at Volvo’s ConExpo-Con/Agg booth this past March. Since May, it has been in the hands of Q & D Construction, Sparks, Nevada, which has been using it to excavate the 40-acre lake site. And in mid-August, a select group of Volvo customers previewed it in Nevada.

“It’s been a digging fool,” says Lee Ruff, equipment manager for Q & D, a diversified firm that builds everything from roads to multi-million dollar estate homes. “What catches your eye is how compact it is for a big machine, and yet the boom is massive and stout.”

Q & D operator Keno Sanchez echoes Ruff’s comments. “It’s like running a small hoe in a big body – it’s just that much smoother than any other machine I’ve run of this size.”

In fact, Sanchez complained when Volvo had to take the EC700B down for three weeks this summer for an engine emissions update, reports Joel Escalante, Volvo’s product manager for hydraulic excavators. “He told me, ‘You guys spoiled me with this machine,'” Escalante says.

“It’s been an invaluable tool to dig this lake,” says Danny Allen, Q & D job superintendent. “It’s got a nice long boom on it, so it’s got a lot of reach. The excavator’s definitely meeting the production demands. We really noticed it when Volvo took the machine out of service for those three weeks.”

Although North American deliveries of production units are not slated to begin until January, the EC700B LC has already generated orders. Q & D has asked for two machines, and one of the customers who attended the demonstration wanted to buy the field-test unit.
The EC700B LC represents a sizeable jump up in size from Volvo’s previous large machine, the 47-metric-ton EC460B. “With our market dominance of our larger articulated haulers, we were quite simply missing the opportunity to fill them,” explains Tim Frank, vice president, Volvo excavator business line.

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Volvo also saw North American customers buying larger excavators because of deeper trench depths, Escalante adds. Denny Tallman, branch manager for Volvo dealer Arnold Machinery, sees the EC700B LC playing a key role in the hard digging required around Reno in site development. “Developers are now going into the foothills around here,” he says, “which have more rock and need bigger machines to dig.”

In addition to site development, Volvo sees the machine doing high production trenching, major sewer projects, quarry rock loading and rock-face stripping. While the Reno unit is the only machine being field tested in North America, there are other demonstration machines in Sweden, Turkey, Korea and China using either mass-excavation or general-purpose setups.

“It’s so well balanced, you know you have a lot of control when you’re in the seat,” Sanchez says. “It’s solid so you don’t get any rocking or teetering.” The machine’s stout undercarriage, wide track gauge and heavy counterweight create this stability, enhanced by the long 43-foot-5-inch track length and 11-foot track gauge.

Before the machine was sent to Q &D it went through a number of factory tests. After these tests Volvo replaced the superstructure panels on the machine with stronger material and installed a pattern control exchange valve. In addition, the main pump, swing motor and bearing and track rollers are similar to those found on 80-ton machine class excavators, says the company.

The machine can be outfitted to the task at hand, using either a general- purpose boom and arm for typical work, a short boom and arm combination for mass excavation or a long arm for added reach and depth. Also available are three types of double grouser shoes to deliver the grip and traction needed in various ground conditions.

Volvo paid particular attention to the cab with the EC700B LC, which has a similar layout to the company’s other B-Series excavators. The cab is supported on hydraulic dampening mounts to reduce shock and vibration levels. Along with sound-absorbing lining, these mounts also help the machine achieve its low 74-decibel in-cab noise level.

Sanchez says he particularly appreciates that the front windshield can easily slide up into the ceiling and the lower front glass can be removed and stored in the side door. “The windshields are easy to handle and lightweight,” he says. Expansive glass and a thin front window crossbar provide a clear all-around view of the work site.

The standard nine-way-adjustable, air-suspension seat, combined with a joystick console that moves independently, helps operators find a comfortable position. Low-effort controls lessen fatigue.

The cab on the EC700B LC has 26,000 BTUs for cooling and 28,500 BTUs for heating. With 13 directional vents (eight on the ceiling, one in the middle and four at the bottom), the high-capacity climate control system keeps the cab comfortable. Fine-particle air filtration keeps dust out of the cab and away from the operator – and the excavator’s computer components.

Service access is made easy with wide steps and ladders on the excavator’s super structure. The anti-slip, perforated-plate walkway helps service people keep a safe footing. Filters and components are conveniently placed and technicians have ample space for service work. There’s also an access ladder to the top of the machine behind the cab.

“The serviceability is phenomenal,” Sanchez says. “They even have mounted an electric power lube system in the compartment underneath the stairs on the right side of the boom.” Both sides of the machine feature easy access, and the counterweight can be installed and removed hydraulically.

The in-cab Instrument Electronic Control Unit, or I-ECU, shows the machine status and gives diagnostic information on all vital machine functions. It allows for easier problem diagnosis and quick fault notification. Other available computerized service tools include VCADS, which traces any problems with the machine’s electronic system, and MATRIS, which offers a detailed report and analysis of the machine’s operating history.

All off-the-production-line EC700B LCs will have Tier 3 engines. “We’re not just field testing the machine with our demonstration units, but also the engine,” Escalante says.

The six-cylinder Volvo D16E EAE3 engine offers fast response to changes in engine load, essential for achieving high performance during tough trenching tasks in mass excavation operations. The turbocharged, four-stroke diesel has water cooling and direct injection, and was specifically developed for excavator use. The unit’s automatic idling system reduces engine speed to idle when the levers and pedals are not activated for a set period, resulting in less fuel consumption and lower cab noise levels.

The Volvo Advanced Combustion Technology engines, introduced by the company this year, are characterized by enhanced fuel injection and air handling control. One prominent feature is the company’s I-EGR design, or Internal Exhaust Gas Recirculation. In this design, the exhaust rocker arm is fitted with a switchable double rocker device that allows for a small second opening of the exhaust valve. This in turn allows a controlled amount of exhaust gas to be fed back into the cylinder during the inlet stroke. The I-EGR system is electronically controlled by the engine management system based on machine and engine operating conditions.

The Reno unit has been averaging 11 gallons per hour in fuel consumption. “This is excellent considering we have a Tier 3 engine on this machine,” Escalante says.

“The tandem hydraulic pumps are coupled directly to the engine to avoid power losses between the engine and the hydraulics,” Escalante says. Volvo uses case drain filters to maintain a cleaner hydraulic system.

The model’s automatic sensing work mode hydraulic system offers these options:

  • Summation system, which combines the flow of both hydraulic pumps to ensure quick cycle times
  • Boom priority, which gives priority to the boom for faster boom raises when loading or performing deep excavations
  • Arm priority, which gives priority to the arm operation for faster cycle times in leveling and for increased bucket filling when digging
  • Swing priority, which gives priority to swing functions for faster simultaneous operations
  • Power boost, which increases all digging and lifting forces

The unit’s swing system uses two axial piston motors driving two planetary gearboxes for maximum torque. An automatic holding brake and anti-rebound valves are standard.

Each track is powered by an automatic two-speed shift travel motor. Track brakes are multi-disc, spring applied and hydraulically released.

Q & D’s complaints on the machine took the form of minor quibbles: the fuel strainer needed to be deeper, the horn louder, the vandal covers should be stronger and there should be larger markings on the dipstick.

And, added Sanchez, please widen the spray pattern on the windshield wiper. “They were telling me to complain more,” Sanchez laughs, “but that’s all I saw.”

When Q & D receives the production models it has ordered, Ruff will put them to work on his pipeline crew. “They typically go into hard and deep jobs where this type of machine is needed,” he says.

EC700B LC Quick Specs

Engine Volvo D16E EAE3 at 1,800 rpms
Net hp 424
Boom length 25′ 3″
Arm length 11′ 8″
Overall length 43′ 5″
Overall height 15′ 1″
Maximum dig reach on ground 42′ 4″
Maximum breakout (SAE) 67,750 lbs.
Fuel tank 222 gallons
Hydraulic system, total 173 gallons
Hydraulic tank 92 gallons
Maximum drawbar pull 101,830 lbs.
Gradability 70 percent
Standard shoe width 36 inches
Ground pressure w/ 36-inch shoe 10.7 psi
Track gauge 11 feet
Ground clearance 2 feet, 10 inches

Standard equipment includes a hydraulically removable counterweight, fabric seat with heater and air suspension and pilot-operated wrist-control joysticks with three switches each.