Construction

Digging With the Big Boys

The largest excavators are becoming more versatile.

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Credit: Hitachi
A Hitachi 870LC moving dirt
Excavators come in all sizes, from dining-room-table-sized mini excavators to the standard mid-sized machines. Yet even those pale in comparison to the largest excavators on the market. These behemoths of digging, these titans of exhumation are the types of tools that some construction industry members have dreamt of using since they were children, playing pretend in their sandbox. These big boys mean business.

They also bring in a good deal of business within certain parts of the construction industry. Behind the awe-inspiring size and sheer strength of these excavators is an amalgamation of technological advances decades in the making.

“These excavators are fast and powerful,” says Jonny Spendlove, John Deere and Hitachi product marketing manager for excavators, discussing Deere-Hitachi’s latest models. The two companies have a cooperative arrangement under their Deere-Hitachi Construction Machinery Corporation. “Whether trenching, lifting, truck loading, or performing other applications, these machines will get the job done quickly.”

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It’s a marvel that these giants don’t fumble and jerk like the trolls of ancient lore. Rather than imagining the giant from Jack and the Beanstalk clamoring about—all the while shouting “Fee-fi-fo-fum”—these machines are masters of dexterity and poise, closer to the power elicited from the ancient Greeks’ Colossus of Rhodes than fairy tale villains.

When an operator moves the boom of a giant excavator, unearths a pile of dirt and rock the size of a moving van, the bucket glides into the pile and lifts it high into the air, the excavator’s house rotating on the spot smoothly, losing little dirt to shakiness.

Improvements in the versatility and efficiency of large excavators follow a trend to make excavators, from the smallest to the largest, better suited for multiple needs. The versatility of excavators that have been rolled out in the past few years reflect the changing technological landscape of North America and Europe. From remote access for diagnostic tools to automatic digital grade selection tools, large excavators are not the same tools they’ve always been.

They’re also just straight-out bigger.

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How big are we talking? It seems like they get larger each year, but large excavators are roughly 90 tons or more. The biggest of the bunch is used for mining cleanup. Bucyrus’s RH340B model weighs about 625 tons and Caterpillar’s 6060 model weighs about 630 tons. Hitachi’s EX8000-6 mining excavator clocks in at about 900 tons. Terex’s RH400 model outdoes them all at just more than 1,070 tons.

Even ignoring weight (and really, how could you ignore something that weighs about as much as 150 elephants?), the Terex can run while moving 980,000 kilograms of material in its loading shovel. That’s as much dirt as roughly 675 US Army tanks, in terms of weight.

Excavators like these tend to range in size, but the largest of the bunch is 10 meters tall with a meter of clearance under the house from the ground.

Even getting these massive machines to and from trade shows can be a challenge. In a video from Awesome Earthmovers, a heavy equipment YouTube channel, a Caterpillar excavator is removed from a showroom on a snake-like loading truck. As the excavator passes by, a worker nearby is dwarfed by a shovel that two people could comfortably lay inside.

Some of the attachments themselves weigh hundreds of tons, and it’s common to see onlookers at trade shows and conventions taking pictures standing next to a giant attachment, miniaturized in a way that can only be achieved by comparison to 500-ton shovel. The multiple-story-high houses cause jaws to drop and eyes to bulge, but it’s really their ability to achieve jobs that were previously impossible that is impressive.

Large excavators are necessary for jobs that range from the every day, such as construction on a local highway, to the complex, such as underwater dredging for a Dubai port.

Other popular uses for large excavators could include pipe moving, metal beam moving, concrete removal, fast dirt removal, and generally any other job that includes moving large, heavy objects or a job where speed is a necessity.

Making these machines versatile isn’t easy, but it saves customers valuable time, money, and headaches when they approach complex, gigantic jobs. And while these excavators are unique for their size, using them can be a fairly common experience. In fact, for some contractors, it’s an everyday occurrence.

“At the larger end, you’ll find excavators anywhere heavy lifting or material handling is required,” says Spendlove. “This could be anywhere from a quarry to a roadside.”

Mega excavators are often used for mining and dredging. They’ve been used for mining in difficult conditions in developing nations like Mozambique, according to Hitachi, and the famous Athabasca oil sands located in Alberta, a Canadian province in the nation’s Northwest corridor.

The oil sands are particularly difficult to excavate because of the viscosity of the material changes throughout the year. Both consistencies are tough. The oil sand at some points clumps together tightly, forming thick clumps that need to be almost pried away from the larger block. At other points, the sand is goopy and softer and becomes closer to a flowing product. This makes it very thick and the bucket needs a large amount of force to break through and scoop up the sand.

The mining process for open-pit oil sands consists of removing the soil, trees, and rocks on the surface, then digging past any peat bog, sand, and clay until the oil sand ore is reached. Large, mega-sized excavators are used to maximize efficiency and due to the complexity of removing soft material that is so heavy.

Oil sand ore contains bitumen, also known as asphalt, which is a sticky, black form of petroleum with a high viscosity that is used for pavement, roofing, and waterproofing in some cases. Oil sand ore is removed by these large excavators after any material that is covering the oil sands is removed and after the area is drained of water. Smaller excavators are typically used to remove dirt and other material like clay that covers the oil sand.

The excavators used specifically to mine the Athabasca oil sands in Alberta (AB), Canada, have to be able to withstand cold that averages -10°F, among other conditions like fine sand that gets into gears and hydraulic lines. Unless the mine has been dug down to the rock, the soil can also be unstable.

Dredging operators use excavators to remove mass amounts of clay, dirt, and rock from underwater environments to expand ports and waterways so large ships can make berth. To fit Panamax and Post-Panamax ships into legacy ports, these ports often require dredging since the waterways were built when cargo ships were significantly smaller.

Excavators are fitted with a dredge pump attachment that irritates and stirs up the soil to turn it into mud. The dredge pump attachment then sucks out that highly viscous mud to widen the waterway. The mud removed requires a large amount of force to pump out because of its high viscosity—the mush looks more like a slurry or a sludge than the mud you’d see children jumping in after a hard summer day’s rain—so large excavators are more up to the task. Some excavators are specially equipped to be amphibious excavators and can be used in aquatic environments like swamps, bogs, and marshes.

Excavators are also ramping up and digging into cutting-edge technologies, inside and outside of the house. Away from the job site, virtual reality simulations are beginning to be used to train new operators on how to use these excavators without risking damage to the machine or downtime due to an inexperienced operator. It’s becoming more and more common to see excavator houses equipped with buttons and screens and joysticks rather than only the levers and pulleys of pre-hydraulic, pre-internet-age excavators.

All of this technological advancement brings additional power, dexterity, and versatility to small and large excavators alike, saving contractors time and money in the long run, excavator makers say.

Brian Stellbrink, product application specialist for Caterpillar, says his company’s newest large excavator models are a vision in efficiency due to these technological enhancements. When a contractor gets to work on a job site, all the sensors and data management equipment work together to get the job done on time and to specifications.

“Our next generation 20-ton excavators come equipped with a ‘digital heart’ to help them work efficiently at the job site,” says Stellbrink.

The future of excavators is digital, as demonstrated at last year’s ConExpo-Con/Agg combined conference in Las Vegas, NV. At the convention, brands touted their telemetrics and sensors that turn traditional machines into high-tech tools.

There has been excitement about adding sensor arrays, data analytics, and even autonomous driving to the excavators of tomorrow.

But before operators can think too far into the future, it’s important to consider the practicalities of the jobs they have on hand.

Picking the Right Size
When choosing the right size for a job site, there are a number of questions a contractor or construction worker will need to ask himself or herself. Some jobs are best done with a compact (otherwise known as mini) excavator and some jobs require a much, much bigger bucket.

Let’s say you’re looking to pick an excavator for a job that involves moving earth, rocks, and demolished material. The question you’ll want to start with is simple: What is my goal for this job?

Clearly, the goal is to get your job done on time and to specifications. But within that, are you optimizing for time? For perfection with your grade? Are you trying to avoid renting out two different sized excavators to get you main job done when you’re also facing a specific but complex challenge? What are you not willing to compromise?

From there, Spendlove says, you can consider these more nuanced questions:

How much dirt needs to be moved in what period of time?

How many trucks will be moving that dirt and how big are the trucks?

How many passes of an excavator to each truck will optimize that operation?

When choosing the size of a bucket, which will limit the excavator size to a specific range, you’ll want to consider lift capacity carefully, he says.

He says the excavator attachments that are most in demand at the moment are the thumbs, grapplers, couplers, and hammers.

“It’s important to find an excavator that will safely and productively get your job done,” says Spendlove. “Consider the stability of the machine and the track width in this calculation.”

Various size excavators are useful for different jobs. Mini excavators ranging from 2,000 pounds to 9,000 pounds are best for a job that includes digging small holes, such as landscaping and pipe laying, and some types of demolition work. They’re particularly great for digging holes and trenches and fitting into tight spaces that other excavators can’t reach, but they can also be outfitted with attachments such as mowers, augers, grading buckets, and concrete breakers. Their versatility shows that they might be small, but they are mighty.

Mini excavators, also called compact excavators, have been touted as an alternative in some scenarios to mid-sized excavators due to these machines’ efficiency. However, they’re particularly useful when space is a consideration. Urban environments can pose a challenge for excavators, and mini excavators maneuver tight corners better than their larger counterparts. They can get around tight spots, but they probably aren’t your go-to tool for the heavy lifting and even for the majority of your everyday work due to the amount of time required to achieve the grade and depth you want.

Mid-sized excavators, which usually range between 6 metric tons and 50 metric tons, are the most versatile and are used for pretty much every job you can think of. “Everything from scrap handling to trenching to pipe laying or various other applications,” says Spendlove.

Mid-sized excavators can also be equipped with a variety of attachments to achieve your worksite goals. Need to smash through concrete and space isn’t a concern? You’re probably going to pick a mid-sized excavator with a breaker. Need to level out some dirt before a house is built? It’s possible you’ll see a mid-sized excavator with a grading bucket at that job site.

Mid-sized excavators are the workhorses of any established construction fleet. They’re also the most common because they have more power than a mini excavator without the cost of a mega excavator. However, it’s worth noting that the specific range of “mini” versus “mid-sized” versus “mega” is evolving as the industry changes and can be, at times, subjective based on a company’s offerings.

What’s on the Horizon
The future of excavators, much like the whole of the construction industry, rests in digital and physical upgrades that improve performance, efficiency, and versatility. Bites and bits are particularly important, but they aren’t the whole package.

The advancements in excavator maintenance and usage are expected to help operators work faster, do their job more accurately, tackle more jobs, diagnose problems earlier, and fix problems when they do arise. Getting these enhancements to the market at large isn’t easy, especially in an industry where machine operators do not regularly replace or upgrade their fleets. Some enhancements aren’t available in all sizes, and some are only available with certain retailers. Consider the playing field like smartphones: They all do the job and they do it well, but which tools to use to achieve specific goals or to make your life a tad easier aren’t going to be available in one easy-to-access package. At least, not yet.

Some of those enhancements are with excavators’ hydraulics systems. Three-pump hydraulics systems are an exciting advancement within the excavator space, Stellbrink says. He also notes that some excavators have pre-programmed grade references that operators can choose. The list goes on and on in terms of advancements across the industry.

“Three-pump hydraulics, grade reference, and machine monitoring are a few of the technologies that are improving productivity and uptime for our customer,” says Spendlove.

Some excavators, like Caterpillar’s models, include their JDLink/ZXLink technology and have the ability to be controlled remotely. The machine owners can monitor was is happening with their excavators—everything from fuel consumption to geo-fencing to productivity.

Remote applications in excavators don’t stop there. Some excavators include the ability to diagnose downtime issues from the dealership so the repair team can arrive on site with the problem figured out and the solution in hand, Stellbrink says. “This saves our customers time and money,” he adds.

At the 2017 ConExpo-Con/Agg in Las Vegas, NV, Willy Schlacks, co-founder of EquipmentShare, told convention-goers about some of the benefits of telemetrics, which is a type of computerized data collection in which data is sent from remote points—in this case, the excavators—to receivers for examination and analysis. Schlacks said in an October 2017 ConExpo-Con/Agg article (Source: www.conexpoconagg.com/news/october-2017/the-excavator-of-the-future):

“Telematics allows contractors and heavy equipment owners to manage dozens of pieces of equipment all in one place. Telematics also increases productivity, reduces costs, and arms contractors and equipment owners with the data necessary to predict and prevent downtime and maintenance. […] By aggregating large amounts of equipment data over long periods of time, telematics solutions help power artificial intelligence and the predictive analytics required for automation.”

Data itself is also being mined from these mining excavators, and that information is being used to help operators do their jobs better on the machines they currently have. That data is also being used to create even better excavators in the future, he added.

“Today we are increasingly seeing construction companies integrate cloud-based software to shift their data from silos to one centralized platform. This gives the entire team access to real-time project data—from human resources information to daily logs and requests for information—on any Internet-connected device. In result, teams can make quicker, more informed decisions with the data.”

The hype around autonomous cars might be more mainstream than autonomous excavators, but there was even talk of such an advancement at ConExpo-Con/Agg 2017. The path to adopting autonomous excavators has been slow, Steve Shoemaker, chief engineer of excavation division, Caterpillar, said at the convention.

Imagine a day where excavators can roll into dangerous environments or impossible dig sites—think underwater, in toxic environments, or even in space—and can read the land around them, dig to a specific grade and tuck themselves back into a maintenance area when their fuel is low. Current autonomous models aren’t there yet, but autonomous capabilities are an addition that is exciting to some people in the construction field at the moment.

Time will tell when, and if, these enhancements spread to the industry at large since autonomous capabilities are so new to the industry and conversations about policy around their use has been so nebulous to date. Shoemaker said autonomous excavators are certainly not science fiction, and productivity is beginning to improve in this specific space.

In the same October ConExpo-Con/Agg article, Shoemaker said, “Productivity on the construction site has been elusive for many years. As the excavator migrates towards autonomous capabilities, our customers can expect to see gains in their profitability in both total cost of ownership, direct fuel costs, and time to complete jobs.”

Excavators range in size and function, and each job requires its own goals that will inform which size of excavator is best for your needs and your particular job site. While the largest of the large are the newest types of machines to join the ranks, the enhancements cropping up across the field ensures mega machines won’t be the last innovations to hit the main stage.

Maybe they’ll even make an appearance one day soon at a job site near you. GX_bug_web

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