Acorn’s Kobelco ripping up trees

We’ve all seen and been held up in the Smart Motorway schemes that are currently being undertaken across England. Large sections of the main motorway network are in the process of having their hard shoulders turned into running lanes in a bid to alleviate traffic congestion. With the hard shoulders being potentially removed, many of the embankments are having to be strengthened or increased in size to accommodate new emergency refuges which are situated every 800m.

The multi-billion-pound projects are deemed to be a tenth of the cost per mile compared to a full widening scheme and are currently being undertaken across almost every major motorway in the country.

EARTHMOVERS were invited to one of the sections currently being worked on, not to see the construction works itself, but the preparatory works which takes place before the construction teams start work. The sections requiring work usually take the existing hard shoulder away, stabilising the embankments before constructing a running lane. Many miles of the UK’s motorway network have verges covered in vegetation which requires removal before the construction work commences. With traffic management in place to reduce the width of the running lanes, the verges need to be cleared in readiness for the construction works to commence. In some places the extent of this work can be just a scrape over with a bucket whilst in the main, the work involves a great deal of clearing and remediation before the construction teams start.

One of the first contractors to be involved in many of the schemes are Acorn Environmental Management who are centrally based in Redditch. Run by Kevin O’Rourke and operating in a wide variety of environmental disciplines, the company has undertaken many of the clearance and de-vegetation tasks on many of the schemes over the past few years gaining a good reputation for safe and reliable delivery of the sections back to the development teams.  One of the current schemes being worked on has come off the back of similar projects for the delivery team where the company used a number of hired in excavators equipped with shears and mulchers along with a lot of hand clearance to reduce the vegetation. Not only are Acorn undertaking the clearance work for the widening scheme to progress, they have also secured the package to provide the ecology surveys, something that works hand in hand with the clearance teams. “We undertake regular surveys of an area prior to de-vegetation.” Kevin explains “Once we know an area is clear, we have to respond very quickly and start the work so to avoid the risk of any birds nesting in that area.”

With the contract awarded for this section, the company made the economical decision to purchase a pair of excavators themselves to undertake the work. “We looked at a number of manufacturers before plumping for the Kobelco.” Kevin explained “We had heard excellent reports on their build quality and reliability and this is what lead us to the door of Molson.” With the brand choice made, the model was equally easy to choose. “We have to ensure we keep our machines to a smaller size.” Kevin comments “Whilst we could’ve taken a 24t compact tail swing model, we looked further away from this contract and decided that the smaller 14.5t SK140SRLC-5 would be able to work in some of the poorer underfoot conditions we can occasionally undertake. Whilst a conventional counterweighted machine would have been an ideal choice to work with the large Trevi Benne shear attachment, the requirements for working on the motorway projects precluded this. “The machine can easily handle the shear but when it has got hold of a large tree, the weight over the front end can vary wildly.” Kevin states “Saying that, our drivers are very cautious and will not take off more than they think the machine will cope with.” Even at full stretch the Kobelco was able to handle some impressively sized trees and Kevin believes that in a normal operation where the machine is able to get closer to the tree, the stability will not be an issue. Along with a full installation of auxiliary hydraulic services to power the shear or grab, both machines have been fitted with a full boxing ring and 360-degree camera systems. Luminous Chapter 8 striping has been affixed to the counterweight whilst the boxing ring, handrails and steps to the undercarriage have all been sprayed in the luminous yellow paint. To protect the operators from errant trees and branches, both machines have been fitted with solid looking cab guards protecting the cab top and windscreen. Additional guarding to both the slew ring and track motors has been fitted and for the darker days of operation, no fewer than 18 independently switched LED lights adorn the upper structure. Whilst the newer machine carries the Trevi Benne tree shear, the older of the two excavators is usually found sporting an Intermercato rotating grab which is ideal for handling the material and feeding it into the Bandit chipper.

We went out to the side of the motorway to see the pair of Kobelcos in action working alongside one of Acorn’s Bandit tracked chippers.

Whilst many sections of Acorn’s work involve them working off the existing hard shoulder, ideal for the zero-tail swing machine, this small section involved a larger expanse of undergrowth on quite a steep drop away from the main carriageway. Regular operator of the shear equipped machine, Sammy Ekins was able to track his way into the undergrowth and systematically start delimbing the large trees which were running alongside a palisade fence and the bottom of the bank. “Although the area has been cleared of any cabling before we start work, we still have to be vigilant just in case there is any unidentified cable or ductwork which might have been missed.” Kevin explains “We sometimes have issues with branches and roots running through these fences and the drivers are very steady when it comes to removing the last bits of tree to ensure the fences are left standing and undamaged.” Even though the Kobelco has been taken with the dozer blade option, Sammy chooses not to use it on most occasions. “The machine is very well balanced at the best of times.” He says.

Essentially both machines are standard SK140SRLC models. Powered by an Isuzu 4-cylinder diesel that develops 78.5kW the engine meets T4Final requirements through the addition of SCR technology. The tried and tested build of the Kobelco may have been the key point for Kevin when it came to purchasing both excavators and this has certainly been borne out with both machines having been extremely reliable since they arrived on the fleet. “We have opted for a service contract on both machines.” Kevin stated “This will ensure that we can keep the machines running and on top of the game for as long as they are on the fleet. We need good reliable equipment on here to ensure we can meet our program and ensure the main construction teams aren’t held up and can meet their programs too.”

With the newer excavator making quick work of removing the trees in this section, the second machine was called into action. With only the hard shoulder to run on, the team work carefully to close off both sides of their working area before positioning an 8-wheeler with 40-yard roll on-off bin in front of the chipper. With the discharge chute of the Bandit inside the bin, the material was steadily fed into the Bandit. The Bandit Intimidator XP has a capacity of up to 20 inches and is more than capable of handling the timber on this project. “We are so pleased with the Bandit, we have another on order.” Kevin explains. The tracked chipper weighs in at just under 10 tonnes and is powered by a 275hp Cat diesel. Not the quietest of machines, it is easy to see why Kevin and his teams have been suitably impressed with its performance. Taking the brash, branches and trunks through its wide opening, the chipper very quickly and effectively fills the waiting truck with chips.

“While we still undertake some clearance by hand, we are now moving away from it to use an excavator mounted shear.” Kevin comments “It is quicker, easier and far safer than having lads on the ground using chainsaws. There is a huge reduction in HAV incidences and using an excavator to remove the trees reduces any issues of injury with men having to clamber over rough terrain.” The benefits to both operator, contractor and their client is easy to see with the teams able to complete a section very safely and very quickly. Having the right tools at your disposal makes it simpler. “We are looking to get a second outfit commissioned soon.” Kevin said, “We want a pair of excavators with a Bandit and having the second team working will enable us to get rid of the hired in machines we have working elsewhere on the project.” Kevin is upbeat about the work his company is able to undertake thanks to mechanisation. “We are now looking at other large projects along with our regular work for Highways England and feel our move into owning our own fleet of excavators and chippers will benefit us in the future.”

Written by Paul Argent for Earthmovers magazine.