Moving Overburden Efficiently, Sustainably

The latest innovations from suppliers speak to both persistent and emergent challenges

by jesse morton, technical writer

A number of new Tier 4 Final excavators were introduced recently, including a big one. They offer preprogrammed work modes that target lower emissions, higher efficiency or optimal production. Mechanical upgrades mean better reliability, higher uptime and a longer life. That they launch now could suggest demand is strong.

When asked about demand in the space, a vice president at a specialty truck beds maker said business is indeed brisk. It should be noted, he said, that the company typically sells beds as retrofits on trucks that have outlived their warranties. Nonetheless, he said, work is steady.

Either as an indicator of current market strength, or in spite of the lack thereof, the latest round of innovations by suppliers in the haulage and loading space speak to the most basic need of operators, higher productivity. They also speak to a growing need arising from operating in the modern world, improved sustainability. A glance at the latest headlines from the around space illustrates.

Excavators Offer Better Reliability, Durability

Hitachi’s new EX-7 Series of hydraulic excavators have several features designed to optimize fuel burn, increase productivity, and ensure operator comfort, company engineers told Coal Age.

“With an array of new technology, they get the job done,” Jim Plourde, mining engineer, Hitachi, said.

Manufactured in Japan and available in the U.S., Canada, Latin America and Brazil, the EX1200-7, EX2600-7, EX3600-7 and EX5600-7 all “feature technologies that reduce fuel consumption costs while achieving superior productivity and enhancing sustainability,” Jordan Popp, mining engineer, Hitachi, said.

The EX2600-7, EX3600-7 and EX5600-7 each come with either a Cummins or an MTU Environmental Protection Agency (EPA) Final Tier 4 (FT4) engine option. For deployment to sites in non-regulated countries, those units come with an engine option that features Fuel Consumption Optimization (FCO).

“For example, on the EX3600-7, the FT4 engine, which also has FCO technologies but uses Diesel Exhaust Fluid (DEF), (an exhaust after treatment solution,) contributes toward 4% net fluid savings,” Plourde said, “while the FCO engine without DEF features a 7% net fluid savings as compared to the EX3600-6.”

The series offers improved reliability and durability over the EX-6 Series.

Contributing to increased uptime, “contamination sensors in each main pump help reduce the risk of machine faults by detecting excessive contamination and alerting the operator when needed,” Plourde said.

Popp said the EX3600-7 is “loaded with intelligent features” to maximize uptime. “Machine pins and bushing life is extended with the help of the new auto-lubrication system with a large-capacity grease tank, a new grease pump, an in-line grease filter with breather, and a grease level indicator in the cab help reduce downtime.”

On each unit, the hydraulic hoses were switched from an arched to an underslung configuration, reducing hose deflection.

Other features were designed to target increased productivity and efficiency. “We packed in so much new technology, like main pump electric regulators on each individually controlled hydraulic pump, that enhance engine power, lower fuel consumption and increase productivity to lower the total cost of ownership,” Popp said. Such illustrates that the company “knows the importance of strong productivity and increased uptime.”

Accordingly, the cab was designed to ensure maximum operator comfort. It has a “best-in-class operation station that offers increased visibility and comfort with ergonomic controls to help increase productivity,” Plourde said. “An advanced multi-display monitor also helps improve the machine’s performance and uptime by providing more accurate operating status information.”

Optional is the Aerial Angle, which is described by the company as a 360° vision system that helps contribute to jobsite safety. “This customer-favorite system assists with noting equipment surroundings through a display monitor that combines a set of images captured by cameras positioned at different locations around the machine,” Popp said.

The smallest in the series, the EX1200-7, has an operating weight of roughly 130 tons, a maximum bucket capacity of roughly 9 yd³, a gross power rating of 760 hp, an overall width of almost 18 ft, and a rear-end swing radius of about 16 ft.

As a backhoe and with a 9-m boom, it has a maximum digging reach of roughly 50 ft and a maximum digging depth of roughly 30 ft. As a loading shovel with a 6.5-yd³ bucket, it has a maximum digging reach of close to 38 ft and a maximum digging depth of close to 16 ft.

The company describes the EX1200-7 as one of the more versatile units in the series and as an operator-friendly machine.

The biggest in the series, the EX5600-7, has an operating weight of 600 tons, a maximum bucket capacity of almost 45 yd³, a gross power rating of 1,540 hp, an overall width of 34 ft, and a rear swing radius of roughly 26 ft.

With a bottom-dump-type 38-yd³ bucket, it has a maximum digging reach of roughly 66 ft and a maximum digging depth of almost 16 ft.

With a backhoe-type 44.5-yd³ bucket on a 33-ft boom, it has a maximum digging reach of 55 ft and a maximum digging depth of roughly 29 ft.

The company described the EX5600-7 as delivering performance and reliability that is unrivaled in its class.

By investing in an EX-7 series excavator, a customer is subscribing to services provided by the Hitachi Mining Applications Group, which focuses on maximizing efficiency, reliability and durability of the equipment sold. “This team supports customers with technical knowledge, jobsite visits and more to optimize their operation,” Plourde said. “For example, we’ve performed operational efficiency studies to identify areas for operational improvement.”

Hitachi launched the series in April 2019 with the introduction of the EX2600-7 and EX5600-7. The EX1200-7 was introduced in May, and the EX3600-7 was introduced in August. The research and development behind the series was driven by customer feedback, Popp said. “Innovation is a collaborative effort, and includes listening to our customers and their needs.”

Plourde said the series speaks to the company mission of supplying reliable solutions through equipment with best-in-class efficiency, reliability and durability. “We know our customers’ bottom line is affected by those key areas, so we focus on continuously improving and developing new technology that will take our machines to the next level.”

Excavator Offers Efficient Production

Volvo Construction Equipment released the EC950F, a 100-ton-class Tier 4 Final excavator best matched with the company’s 60-ton A60H articulated hauler.

Initial field tests show the unit can load an A60H in four passes with an average cycle time of roughly 25 seconds, Ray Gallant, vice president, sales support, North America, Volvo Construction Equipment, told Coal Age.

“Efficient production is the main benefit of the EC950F,” Gallant said.

Such is made possible by optimized hydraulics, which “deliver constant pressures across each phase of the digging and lifting cycle,” he said. “The hydraulic system increases pump power for fast and smooth operation, while the Posicom hydraulic system controls on-demand flow and reduces internal losses in the hydraulic circuit.”

Features include a boom swing priority valve that adjusts the flow between the boom-up and swing so that truck loading cycle times can be set to working conditions.

“This machine also gives flexibility for using different boom configurations and bucket sizes,” Gallant said. “Using a short boom and short arm can allow for up to a 10-yd³ bucket, which is five times bigger than an average 20-ton machine.”

The attachment management system can store settings for up to 20 different attachments, enabling the operator to preset hydraulic flow and pressure, he said.

The unit has preprogrammed work modes that help the operator minimize fuel burn or maximize productivity. ECO mode, for example, comes standard and offers optimized fuel efficiency.

“The integrated work modes allow operators to choose the best work mode for the task at hand,” Gallant said. The operator can select from Idle, Fine, General and Heavy work mode. “Operator settings allow them to lift quickly and swing slowly to get over a truck, or if they are on a pile or hill to swing more quickly when already above the truck.”

Uptime is maximized by certain design features, to include “the heavy-duty boom and arm,” the “strong frame structure, heavy-duty underside plate and floating pins on the bucket connection,” and the “optional full-length track guard,” Volvo reported.

The unit comes with a “low-noise and spacious cab,” the company reported. It has “high-visibility handrails, conveniently positioned steps” and anti-slip plates. “For added visibility, it comes fitted with a rearview camera.”

Options include Dig Assist, and 360° Volvo Smart View, and a Falling Object Guard or a Falling Object Protective Structure.

Company literature states the unit has an operating weight of roughly 100 tons, breakout force of 77,000 pound-feet (lbf-ft), breakout force of 79,000 lb-ft, lifting capacity of 50,000 lbs, bucket capacity of 9 yd³, a maximum dig depth of 29 ft, and a maximum dig reach of 46 ft. Gross power rating is 600 hp. It is roughly 15 ft wide and has a tail swing radius of under 16 ft.

The excavator is eligible for ActiveCare Direct, a telematics system, free for a year on new purchases, Volvo reported.

The system provides “24/7/365 active machine monitoring and fleet utilization reporting directly from Volvo,” the company reported. “If a machine requires attention, Volvo communicates directly with your local dealer so they can respond quickly.” Further, “customers receive a report to identify areas to improve worksite efficiency, avoid unplanned downtime, and catch problems before they occur.”

ActiveCare Direct “simplifies fault codes and alerts to make the customer’s and dealer’s jobs easier in terms of maintenance and care resolution,” Gallant said.

The excavator comes with a limited frame and structure warranty.

Gallant said the unit is the evolutionary successor to the EC950E, a Tier 3 unit released in 2016 to Africa, Asia, the Middle East, Russia and former Soviet states. “It proved to be a very capable machine,” he said.

The EC950F is expected to build on that success, he said. “The goal of every mine is to get the highest production at the lowest cost per ton,” Gallant said. “That is what the EC950F is designed to do, particularly when paired with the A60H.”

Overburden Beds

Philippi-Hagenbuch told Coal Age the PHIL Overburden Bodies for haul trucks can help increase tonnage hauled, decrease shovel and truck downtime, and increase haul truck operator safety.

“The reason we can do that is because we custom engineer the product for every single client,” Josh Swank, vice president, sales and marketing, said. “We talk to a mine and see exactly what they have and then we design a haul truck body that best works in concert with their loading tools.”

PHIL Overburden Bodies are typically wider for optimal loading. The wider body is easier and safer to load compared to a body not optimally paired with a shovel.

“When a bed and a shovel or front-end loader or bucket aren’t sized in tandem to work together, the operator has to load further up front. They have got to load heavier to the front of the bed.” Swank said. “By doing that you are having to work around the front slope. You have to make sure you are not hitting it.”

Instead, a custom body allows the shovel operator to “fill the bed up with the least number of motions possible, making it super-easy for the shovel or front-end loader to get in there without hitting the body side or needing to work its way around the body side,” Swank said. As a result, “our beds tend to be wider than general purpose beds, which means they can load them faster.”

By providing a larger loading target, a customized body can decrease loading time by up to 50%, he said.

Faster loading translates to increased volume. “If they are loading them faster, that means they can haul more material per day,” Swank said. “You are hauling more material, but you are also speeding up the entire operation.”

Which can translate to decreased truck and shovel downtime.

The wider beds also allow the loader to get down further into the bed before releasing. “You are dropping from a lower height,” Swank said.

“The lower the height you are dropping the material from, the less of an impact on the bed, the less that is being felt by the driver,” he said.

The bodies can be custom designed to minimize bed abrasion, which in turn “helps the material come out in a way that is not a single, cohesive loaf,” Swank said. “That causes a lot of havoc to the truck. It hurts the body pivot area. It hurts the hoist cylinder mount areas. On the safety side of things, with the driver, they feel that jarring as the truck can kind of jump when the load exits the rear.”

As far back as the mid-1980s the company was studying whole body vibration at operations in Australia. “That is a really big concern there, and that is where we learned how significantly we can decrease the jarring feeling,” Swank said. “What we learned in Australia we have taken global with all of our designs. It is just part of our standard engineering practice at this point.”

The company got its start developing automated tailgates in the late 1960s. Over the 1970s and 1980s, it launched and developed its HiVol line of bodies.

“Early on, we got into coal,” Swank said. “Shortly thereafter, the mines that had our product in coal needed beds for overburden.”

After the PHIL Overburden Body, released in 1979, came the HiVol Dual-Purpose Body, released in 1983, which was designed for hauling both coal and/or overburden. “It is very popular,” Swank said.

In the 1990s, the company developed bodies for hard rock mining applications. Later, it launched an oil sands solution.

During the last 15 years, the overburden bodies have evolved for greater wear resistance. “We incorporated things developed for our hard rock bodies,” Swank said.

Currently, the HiVol bodies are deployed “with almost every major mining company in the world,” Swank said. “For the vast majority of our clients, once they start working with us, they continue working with us for the long term.”

Most clients adopt HiVol beds to replace worn out OEM beds. “There are a lot of factors involved in that decision,” he said. “It depends on the mine and their body replacement and upgrade philosophy.”

Some mines will adopt the beds earlier in the truck life. “Sometimes, our clients buy bodies from us for brand new trucks,” Swank said.

In either case, Philipi-Hagenbuch seeks to design a body that not only improves the performance of the truck but that won’t negate any warranties or service agreements. “We work with every truck OEM company to make sure that we are designing our product for that specific make and model of the truck in the way that the OEM designed it to be,” Swank said.

“From a warranty perspective, you have to comply with a few critical requests,” he said. “You have to have the correct weight on each axle, and then you cannot overload the truck’s gross vehicle weight past the OEM’s guidelines.”

Swank said the company has never invalidated a truck’s warranty. “We want to keep on good terms with everybody and we all work nicely together, the truck manufacturers and us.”

When a miner reaches out to adopt a HiVol body, Philippi-Hagenbuch will send a fact-finding team to the mine site to gather information on the operation. “We need to know what their goals are so we can engineer a solution that is going to achieve what they dream of,” Swank said. “Throughout the course of the discussions, we will provide feedback and options, and we might see things that they hadn’t already brought up in the discussions with us. We might offer some additional things that they should take into consideration.”

Such is necessary to arrive at a unique design particular to an operation. “There is no off-the-shelf design that we are going to do for a client,” Swank said. “Occasionally people do call and ask, ‘hey, we need a body. We had something happen. Do you have anything in stock and available that you can ship us?’ No, we don’t. The only thing that we stock is flat plates of steel and the know-how to design a world-class body for your needs.”

That and a deep wealth of experience, having done more than 500 custom designs over the course of the last half-century.

“We have a lot that we can offer,” Swank said. “It comes down to listening to the client, finding what their goals are and what they want to achieve. And then we will go about designing a unique version specifically for them.”

Precision Mining, Layer by Layer

Vermeer reported its Terrain Leveler surface excavation machine (SEM) is ideal for precision overburden and interburden removal in areas of the mine where drilling and blasting techniques are questionable.

“It answers the current issues with drilling and blasting,” Mike Selover, corporate accounts manager, Vermeer, said. “It addresses difficult permitting. It addresses urban encroachment. Where drilling and blasting is restricted, the leveler is not. It provides solutions for working under powerlines, next to buried infrastructure, over gas pipes, over high water tables, and around wildlife. And it answers in a safer way.”

The Terrain Leveler can mine overburden or interburden in these situations because, when equipped with GNSS control, it offers sub-centimeter precision. “That allows us precision that drill-and-blast cannot touch,” Selover said. “If you are chasing a seam, or eliminating overburden, or interburden, or a waste rock, you can do what precision drill-and-blast cannot achieve.”

That level of control is particularly useful for a mine site with either multiple thin but economic layers sandwiched between thin layers of interburden, or for a site seeking to separate layers of overburden.

“If you get into situations where you’ve got waste seams or contamination, you are able to go layer by layer down through it,” Tyler Sikora, application engineer, Vermeer, said. “And as we cut it, we are not mixing it. As we cut it, it is on the ground right where it was. We are not tracking and dragging it through different areas.”

Such enables the miner to easily separate layers for segregation purposes. “You can pile them up and load them out separately, rather than just drill and blast it and it all falls down and mixes together,” Sikora said.

For example, in a couple instances, a Terrain Leveler was deployed to sites with seams so narrow they would be uneconomic if blasted. “That goes back to product dilution,” Selover said. “With the precision of the continuous miner, it allows you to forego the dilution you would get with blasting and instead you get the opportunity to perhaps create product of different grades.”

At both sites, the miner was “able to use the surface miner to take out layer after layer,” Sikora said. “They were able to take off an overburden layer, then a high-grade coal layer, then a low-grade coal layer, and then get back to the next interburden layer. They were basically able to take them all out separately and capitalize on the value.”

Also, by working down horizontally, layer by layer, “you can manage things like water runoff, product sizing, and other things,” Sikora said.

Vemeer’s biggest model, the T1655, was released at MINExpo 2012. Selover described it as the largest piece of equipment ever made in Iowa. “The machine weighs 450,000 lb and is powered by two large diesel engines,” he said. “The advantage of the larger machine is just production, production, production.”

Recent innovations to the line include line-of-site remote control and GNSS-assisted piloting automation.

The Terrain Leveler can be adapted to be controlled remotely with a full-function remote control from inside a pickup or a workstation.

When equipped with GNSS-assisted piloting automation, “the operator is only required to turn the machine around at the end of the pit,” Sekora said.

Other innovations include a pressurized cab with a seat on air suspension. The T1255 offers vacuum dust suppression. “It is a continuous-vacuum self-purging system, as opposed to a water sprayer,” Sikora said.

Perhaps the main benefit offered by the Terrain Leveler is improved safety over that intrinsic to precision drill-and-blasting, Diogo Craveiro, international marketing and training specialist, said. “We all know that safety while working with explosives has been a major focus area at many mines around the world,” he said. “With our precision mining process, normally the workers have a more controlled way of extracting the material, and the process is not one where there is a step that has a high level of energy that is stored and released.”

The Terrain Leveler produces less vibration, noise and dust than does a precision drill-and-blast operation, he said.

Further, “it is not just the nature of the traditional process, but also the number of people involved,” Craveiro said. In most cases, a leveler is operated by one person.

Double Clip Back Bucket for Draglines

Caterpillar reported it released the double-clip back bucket for draglines, designed for increased fill speed and reduced bucket weight for faster cycle times and greater payload. The design eliminates the spreader bar from the rigging system.

The bucket features a “wide mouth, aggressive lip angle, and low front height” to “reduce drag power required,” Cat reported. It minimizes the required fill distance for improved productivity and reduced bucket wear.

Unique trunnion design and location on the clipped portion of the bucket protects the lower hoist link from wear and provides quick dumping of the payload, Cat reported. The design includes a cast-in deflector to protect and increase the life of the trunnion.

The shape of the rear wall enables the bucket to fill without voids, and it increases material density for optimum payloads, the company reported.

The general design enables the operator to see when the bucket is full, “signaling the operator to exit the cut. This promotes increased production with shorter dig times,” Mike Evans, commercial manager, draglines, Caterpillar, said. “It also prevents overloading the machine, which negatively affects reliability, and leads to longer bucket life since it mitigates premature wear created by over-digging.”

Over-digging “causes machine reliability issues and premature wear to the bucket,” Mike Stolz, dragline engineering specialist, Caterpillar, said. “The advantages the Cat bucket offers are tremendous.”

Fewer components mean less inventory management and lower maintenance costs, the company reported.

The bucket is available for a range of sizes and applications. Each bucket is designed for the specifics of the dragline and application, Cat reported.

Separately, Caterpillar reported its 6030 Hydraulic Shovel, the smallest shovel in the line, meets emissions standards while delivering high productivity and reliability. “The 6030 provides the most powerful engine output in its class along with mobility and flexibility,” the company reported.

With an operating weight of 296.5 mt, the shovel offers maximum breakout force of 200,000 lbf-ft.

The shovel has a bucket payload of 30 mt, with a standard capacity of 17 m³, and can fill a Cat 777 in three passes and a Cat 785 in five passes.