It’s got the Power

New Doosan DX520LC excavator provides high output and fuel savings for Banner Contracts

The latest addition to the Banner Contracts fleet operating at Lafarge’s Thrislington limestone quarry near Ferryhill, Durham, is a new 50-tonne Doosan DX520LC crawler excavator which has replaced a Doosan S470LC model. The new machine was purchased from Construction Plant Suppliers, the Cleveland-based Doosan dealers who have been providing Banner Contracts with Doosan excavators for a number of years.

Banner Contracts director Jo Banner explained that while the S470LC had put in some sterling work, the new DX520LC met a need for an excavator that could provide greater output. ‘Our output of crushed rock is governed largely by the rate the crushers can handle it,’ he explained. ‘It is essential that our prime mover, the new DX520LC, has the ability to ensure the crushers are always working to full capacity.’

The DX520LC is powered by a Doosan DV11 six-cylinder engine featuring common-rail fuel injection and rated at 245KW (328hp) when operating at 1,800 rev/min. Each cylinder has four valves which helps improve gas flows and, combined with common rail, results in better combustion and greater fuel efficiency overall.

Doosan’s Electronic Power Optimising System (EPOS) connects the engine to the excavator’s hydraulic system via a CAN communications link, helping to ensure optimum power settings are used to meet the different demands made during digging and loading cycles, and thereby saving fuel. EPOS also provides self-diagnosis capabilities, allowing technical problems to be identified, as well monitoring maintenance and oil change intervals.

Although still a relatively new machine, Mr Banner reports that fuel records are already showing good savings. ‘The excavator works a 10h shift for five days a week, which equates to a saving of 100 litres of fuel a week or more than 5,000 litres for the year, which is an important saving for us,’ he commented.

With EPOS, the operator is provided with a ‘power’ mode that makes 100% of engine power available for heavy work, while a ‘normal’ operating mode can be selected for general excavation, loading or lifting tasks. When digging out the blasted rock and loading it into the crusher/screeners, Mr Banner says his operator prefers to have the machine set to power mode, as cycle times are quicker and operation of the machine is smoother.

In the all important hydraulics department, the DX520LC features two variable-displacement axial piston pumps that have a combined maximum flow rate of more than 700 litres/min. Relief valve settings for the boom arm and bucket are 314 bar in normal mode and 342 bar in power mode when extra operating force is required.

Helping to make efficient use of all the hydraulic power available is a boom and arm flow-regeneration system. This stores the energy created by the oil being pressurized as the boom and arm are lowered and makes it available again when they are raised.

In addition to its output potential, another of the main reasons the DX520LC was purchased by Banner Contracts was its 10.75m reach and 9.6m digging height, which allows it to reach and dress the edges of the blasted areas.

‘The quarry’s geotechnical assessment, which requires a machine with the reach to scale faces safely, makes the DX520LC a good choice,’ explained Mr Banner. ‘It’s an important issue and we are pleased to have a machine that performs so well in this area.’

To ensure that customers such as Banner Contracts get the maximum out of the DX520LC, Doosan know that its work rate is directly linked to the comfort and performance of the operator and have ensured that he or she has a work environment that puts them totally at ease when operating with the machine.

Mr Banner said: ‘If we expect 10h of gainful work a day, then the cab, the controls and the environment have to be just as the operator wants them to be. And it’s good to hear our operator report that he is pleased with the degree of comfort the cab offers in terms of the control layout, the improved visibility, the amount of space and the fully adjustable seat. I wouldn’t expect anything else for this class of excavator.’

Maintenance of the entire Banner Contracts machinery line-up, which extends to over 100 crushers, screeners, washing plants, loading shovels, excavators, dozers and dumptrucks, is carried out by the company’s own team of service engineers.

The low maintenance demands of the DX520LC and the resulting reduced downtime is welcomed by Mr Banner. ‘Engine and oil filter changes are at 500h, which means a service is required about every 10 weeks or so and other oil and lubricant changes are scheduled at increased intervals,’ he explained. ‘Greasing for the boom and arm are from a central service point, which saves time, and there are other features such as a reversible fan, which can be used to blow dust out of the radiators, and good access to filter housings.’

In Jo Banner’s opinion, the new Doosan DX520LC is playing an important role in helping Thrislington Quarry to extract stone in the most profitable and economical way available. ‘To date, it’s been reliable and has managed to achieve all that we have required,’ he said. ‘We couldn’t really ask for more.’

For further information about the DX520LC and other Doosan construction equipment, visit: www.doosanequipment.eu