Located on the property of the Charlotte Douglas International Airport lies a granite formation that is squarely in the path of development for the new Norfolk Southern Intermodal Site.
Under the sweltering summer sun, Plateau Excavation of Austell, Ga., is constructing the $92 million Intermodal project, with the assistance of three Sandvik DX800 top-hammer hydraulic drills that, day after day, no matter what the conditions are, continue to bore away at the task at hand.
The intermodal project encompasses nearly 200 acres (80.9 ha) in total. The granite rock formation lies only within a few hundred feet of a very active runway. The 200 acres officially will be turned into an “intermodal yard,” which means that cargo carried there on Norfolk Southern railroad cars will be off-loaded for further transport on tractor-trailers and vice-versa. An estimated 200,000 cargo containers will be transferred in the yard each year. By 2013, the intermodal project will replace a smaller operation in Charlotte.
Excavating the Rock
Plateau Excavation has grown over the past three decades into a premier site infrastructure contractor. Plateau’s area of work covers the entire southeastern region. The Intermodal rail yards in Charlotte are among numerous site preparation projects the company has successfully completed since 1983. On this particular project, which broke ground in early May 2012, Plateau is the subcontractor for the Illinois-based construction and management firm Milord Company.
Plateau Excavation has upwards of 50 pieces of heavy equipment working on the site including the three vital Sandvik DX800 hydraulic drills boring into the granite shelf. The drills are owned and operated by a Plateau Excavation subcontractor LK Gregory Construction Inc., which is headquartered in Crossville, Tenn. The Ranger 800 is a 2007 model and the two other DX800s are 2012 Sandviks supplied and serviced by the Buford, Ga., dealership of Charlotte-based ASC Construction Equipment USA Inc.
Sandvik is a new product line for ASC, which is primarily a Volvo dealership. Until January 2012, Sandvik Construction distributed its machines directly in the region. ASC took it on that month and when LK Gregory subsequently expressed interest in procuring two more DX800 Series machines, ASC’s Buford, Ga., dealership became “aggressive” in seizing the opportunity to move the 16-ton tracked machines to help Plateau Excavation with its project in Charlotte. ASC’s Charlotte dealership is within 15 mi. of the project, which makes service and parts supply readily available. ASC is the largest Volvo equipment dealer in the world, serving the southeast construction market from 13 locations.
“Although Sandvik was fairly new for us [ASC], we knew there was an excellent opportunity for us with Plateau Excavation,” said Jack Evans, ASC’s general manager of the Buford location. “So we ramped up with the Sandvik line pretty quickly and worked very closely with Sandvik personnel to provide the necessary service and support on site for Plateau Excavation and LK Gregory in its drilling and blasting efforts.”
Evans said the initial experience was sort of overwhelming, equating it with “drinking out of a fire hose.” But ASC recognized the urgency of the matter, realizing that one of Plateau’s first concentrated efforts solely depended on the excavation of the rock. This effort began with the Sandvik DX800s and carried onto a vast array of machinery that Plateau Excavation has at its disposal. With market conditions still constricting, Plateau Excavation has taken this opportunity to again discover alternative methods of saving time and capital by crushing the blast rock into usable material on site. Moving in a portable crushing operation, Plateau Excavation will be able to reduce the size of the rock into everything from rip-rap, 34’s, 57’s, and aggregate base suitable for use on road beds and building pads.
Once the granite is drilled and blasted, Plateau uses a fleet of excavators to tear through the rock, progressing it along the fleet of articulated and off-road trucks to get the shattered rock to the crushing operation situated less than 1,000 ft. (304.8 m) away to expedite production.
Why Sandvik
Plateau Excavation’s owner and CEO Greg Rogers looked to recommendations of LK Gregory’s Vice President Danny Camp to satisfy his company’s stringent production standards. Rogers’ first priority is to maintain schedules set forth by Milord and Norfolk Southern. Camp had previously used (and respected) Tamrock Ranger drills, which represented an earlier generation of today’s Sandvik DX Series drills. Sandvik took over Tamrock, a Finnish company, in the late 1990s.
“They [DX Series drills] just seem to outperform the other makes in a construction environment,” he said. Camp’s crew is well experienced with drills — the three operators performing the drilling on the Plateau project have more than 32 years combined experience operating surface drill rigs in a construction drilling environment.
The DX800 is a crawler-based surface drilling rig that is notably proficient in several critical areas. It pivots 180 degrees on a turntable, which allows the operator to drill more production holes while spending less time having to turn around. By the end of a workday, more time spent drilling and less time spent maneuvering translates into greater productivity.
But with a project of this size, productivity only comes second to safety. The site development at hand is somewhat of a typical construction work environment for the DX800s. Much of the surface is constituted of a mix of rutted rock beds and rubble left from previous site work, a fairly treacherous work platform. Nevertheless, the DX800s are moving across it nimbly and drilling more holes at each station due to its turntable design, according to Camp.
In addition, the DX800 is able to drill into rock vertically, horizontally, or at just about any angle in between. With the boom of its high-rotation torque drill mounted on the turntable, the machine’s operator has unusual placement control of the business end of the drill, using his joysticks to swivel, tilt and maneuver the drill into place, regardless of how fractured or imposing a drilling surface might be.
According to Camp, the most conspicuous advantage the Sandvik drill has is its stability, which is an overriding concern for a piece of equipment that mostly works on hard, irregular surfaces near steep drop-offs. The Sandvik cab’s engineered and certified roll-over and falling object protection is not an inconsequential feature. “The work can be precarious,” Camp acknowledged. “And that is one of the reasons we chose the DX800. It’s widely regarded as a stable machine. You can put it just about anywhere and it will generate production.”
The machine’s ability to remain stable while it drills is partly the result of its cantilevered design. The DX800’s Caterpillar C7 Tier IV engine, along with a gearbox that regulates hydraulic and air compression tasks, is mounted at the rear of the machine’s superstructure. The weight of the power pack thus offsets the boom and drill at the other end. Because it is all mounted on the turntable, the stability is not compromised when the boom is moved from hole to hole. The 2012 models also are the first to be equipped with a Tier IV Re-Gen system, which equates to less emissions and less of an environmental impact.
On the Plateau Excavation project, the trio of DX800 rigs is averaging 700 to 900 borehole ft. a day. The routine is to have the drills bore for one or two days with the grades of the project spanning from 1 to 2-ft. (.3 to .6 m) in slopes to holes running 50 to 60 ft. (15.2 to 18.3 m) in the centerline of the future rail. When the blast site is ready, LK Gregory works side by side with Plateau Excavation, Milord Company, STV (Representatives for Norfolk Southern) and operations at CDIA to ensure site safety is the top priority. Averaging between 7,500 to 10,000 yds. (6,858 to 9,144 m) of blasted rock per blast continually allows LK Gregory to stay in line with Plateau’s production standards. An estimated 300,000 cu. yds. (229,366 cu m) of rock will be removed before the path of the rail line is cleared.
“We have been pleased with the performance and production of the Sandvik rigs on the Norfolk Southern project,” said Plateau’s Greg Rogers.
Prevailing Over
the Rock
Camp called the granite formation being systematically taken apart by Plateau as “some of the hardest rock we’ve worked with.” It is hard, closely compacted granite and nothing short of blasting will dislodge it. Though high-density rock such as granite is hard on a drill unit, it conversely is the best type of rock for blasting, according to Camp. Because of its density, it absorbs more of a blast’s concussion and, thus, the rock is severely impacted by it, fragmenting and displacing a targeted mass, while keeping the seismic vibrations contained in the rock and not transmitted to outlying areas.
Blasting a softer rock is more apt to produce more precarious situations and broader seismic activity, said Camp.
“You would think it would be the opposite, but it’s better to be drilling in a tightly compacted hard rock. It’s slower, but better,” he said.
The DX800s are designed to penetrate any density of rock and in the course of a day, density variations will occur.
“When you are moving across any job, some rock will be a little bit softer in some places than others. You can literally move just feet and the density can change,” said Camp.
Density of rock aside, the hydraulic battering action of the drills against the rock always takes a toll on the machines. (Though not necessarily the operators — the air-conditioned and filtered cab on the DX800 are insulated against the screeching and banging going on outside, with the noise level in the cab maintained at a healthy 80 decibels.) Due to the nature of the scope of work, “the machines beat themselves up all day long, and our morning’s maintenance routines on the drills are as vital as anything else that occurs in our day.”
While the Sandvik drills are a more specialized piece of equipment than some equipment that ASC supplies contractors, they will never be the high volume staples that Volvo excavators and backhoes are for the company. However, Sandvik drilling equipment also has applications in quarry and mining operations. “We cover all those markets,” said Evans.
The DX800s will surely not sit idle in any yard in the near future. Once the Charlotte Norfolk Southern Intermodal Project is complete, Camp said, “Wherever Plateau Excavation goes, we will follow and assist in any way that we can.” Plateau Owner and CEO Greg Rogers said, “We have been pleased by the production of LK Gregory and their Sandvik rigs as well as the response from ASC Construction Equipment USA Inc. At the end of the day, my focus is on our customers, Milord and Norfolk Southern, whom I hope that we exceed their expectations at every opportunity; we look forward to the future with them.”
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