Thomas Armstrong photoThomas Armstrong (Aggregates) Ltd, based at Maryport in Cumbria, England, has taken delivery of two new Doosan DL420 wheel loaders from Carlisle-based Lloyd Ltd, the Doosan dealer for Cumbria and the southern part of Scotland. Operating at the Thomas Armstrong quarries at Overby and Newcowper in Cumbria, the new machines represent the third generation of Doosan wheel loaders to be purchased by the company over the last 10 years.  

The new Doosan DL420 wheel loaders have succeeded previous generation Doosan DL400 wheel loaders which in turn succeeded two of Doosan’s Mega 400 generation wheel loaders formerly owned by Thomas Armstrong.

Frank Harkness, Director of Thomas Armstrong (Aggregates), part of Thomas Armstrong (Holdings) Ltd, said: “The previous Doosan DL400 wheel loaders ran with no major issues for the last six years as had the Mega models before them. The DL400s had each run up an impressive 14500 hours and our drivers really liked them. When we came to replace them, we tested products from virtually every other major manufacturer, but the operators still expressed a strong preference for the new Doosan DL420 machines.”

Low Fuel Consumption

Jimmy Scott, the DL420 operator at Overby, agrees: “I liked the DL400 wheel loader, but the DL420 model offers more power.  The new machine is also a lot better on the fuel side. Official figures say it has 7% more efficiency on fuel consumption, but it feels like it is more when you get to the end of a long day and it still has fuel in the tank.”

The Overby facility is based on a natural glacial sand deposit which is mined directly from the face by the new Doosan DL420 wheel loader. The sand is loaded by the DL420 model into a screening machine which separates out different grades of gravel and sand. The screened sand is then stockpiled by the loader for later use or loaded directly into trucks, mostly owned by Thomas Armstrong, for delivery to customers in the region.

Martin Cueto, the Overby Quarry Manager, added: “The DL420 wheel loader also loads an articulated dump truck which takes the sand and gravel to our packaging plant where it is bagged in robot-controlled systems into 25 kg and bulk bags for delivery to customers including major builders merchants chains such as Travis Perkins, Jewson, Build Center and Keyline. To meet demand, the DL420 wheel loader starts operating at 6.30 am in the morning and works all the way through to 5.30 pm every weekday with a half an hour break for lunch.”

The new DL420 wheel loader at the Newcowper quarry works similar hours and works just as hard but on different applications.  One of the main jobs for the loader is supplying a wash plant which grades materials into different sizes. The Newcowper facility is coming to the end of its working life and so the DL420 is also used for remedial work around the quarry. The wash plant will be replaced in the future by a new system under construction at the Overby quarry.

Thomas Armstrong (Aggregates) Ltd is a founder member and keen supporter of the British Aggregates Association. As well as sands and gravels, Thomas Armstrong also produces graded limestone, recycled furnace slag and other recycled hardcore gravels from local resources for supply throughout Cumbria and North Lancashire. The company has further bagging plants in Glasgow, Durham and Liverpool to supply merchants throughout the North West and North East of England and the central belt of Scotland.

One-Stop Shop

Thomas Armstrong (Aggregates) Ltd is part of Thomas Armstrong (Holdings) Ltd, one of the UK’s largest privately owned manufacturers of building products and suppliers of building services, founded by Thomas Armstrong in 1830. The ever-growing portfolio allows the group to offer a one-stop shop from designing a building, manufacturing the building materials, delivering them to site, constructing the building and maintaining it during its life.

As well as Cumbria, Lloyd Ltd is the authorised Doosan dealer for the southern part of Scotland, covering East and South Ayrshire, the Border counties, South Lanarkshire and Dumfries and Galloway. A family owned business, Lloyd Ltd was established in the 1960s and offers a wealth of experience and dedication to customer care.

Power and performance

With a bucket capacity of 4.0 m3, the 22.3 tonne DL420 loader is powered by an 11 litre turbocharged, electronically-controlled engine with high pressure unit injector system and a state-of-the-art combustion system. The engine develops 209 kW (284 HP) at 2000 rpm and offers a maximum torque of 148 kg.m at 1400 rpm, for optimal traction and breakout force in loading-transport-handling applications. Breakout force is among the highest in its category at 210 kN.

The DL420 offers a static tipping load with bucket of 18.9 tonne (at maximum reach with a straight frame) and a height at bucket pivot point of 4.35 m. Equipped with a pin-on bucket with teeth and tipped forward at 45°, the dump height is 2.96 m and the dump reach is 1.40 m. The turning radius at bucket edge is 6.995 m at the maximum steering angle of 40°.

Operator comfort and convenience were given high priority when the DL420 was designed. Improved visibility, heating and air conditioning, more room, a very comfortable seat, and ample storage space are all features which enable operators to work for more hours with less fatigue. The noise level in the cab is a comfortable 71.2 dB(A) while the external sound level is 104.7 LwA.

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