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Little known wheel loader a surprise packet

Although it’s not a well known brand in the Australian quarrying market, the Doosan wheel loader has so far delivered some impressive results in quarry trials.

In a market with many brands, Doosan is not a brand that regularly springs to mind. It is a mark of how quickly the Doosan DL series wheel loader has become a competitive machine that many people who investigate it are surprised by how good it is.

Doosan has the following wheel loaders available in Australia:
• DL200 (107 kW, 11.3 tonne operating weight, with 1.8 to 2.3 cubic metre buckets).
• DL250 (121 kW, 14t operating weight, 2.4-2.7m3 buckets).
• DL300 (162 kW, 17.3t operating weight, 2.9-3.5m3 buckets).
• DL420 (209 kW, 22.3t operating weight, 3.9-4.7m3 buckets).
• DL450 (224 kW, 25.5t operating weight, 4.5-4.8m3 buckets).
• DL500 (250 kW, 29.8t operating weight, 4.8-5.2m3 buckets).

The Doosan DL420 is a recent addition to the range, replacing the well regarded DL400. The new machine was released at Bauma in Munich, Germany in April 2010 and is upgraded in several areas, notably a larger 11 litre engine providing a seven per cent improvement in fuel economy and increased breakout force of 210 kN. The cab now features more room for operator comfort, improved visibility and an improved Heating Ventilation Air Conditioning (HVAC) system.

The Doosan wheel loader range provides quarry operators with a broad choice of robust and efficient machines in the two to five cubic metre range.

The design of the DL series of wheel loaders demonstrates a good understanding of loaders working in tough applications. The exterior of the loader is all metal, so that any accidental collisions result in dents, not breakages. The step assembly is bolted on to facilitate replacement in the event of damage. The rear counterweight extends beyond the radiator to protect the radiator and lights.

The cooling system is separated from the engine area and draws cooler, cleaner air from the top and side of the machine. While this minimises dust intake, the hydraulic fan (featured as standard equipment) is reversible for ease of clearing the radiator if it starts to clog, and the air intake comprises a cyclone pre-cleaner and three-stage air cleaner for operation in dusty environments.

The operator entry is well designed and has broad, well spaced steps with grab rails on either side. The entry platform extends far enough to the rear of the cab to allow safe cleaning of the rear windows.

Inside the cab, the operator has an adjustable suspension seat and the steering column is adjustable for reach and rake, so that all sizes and shapes of operator can find a comfortable operating position. Further increasing operator comfort is the standard ride control system, which operators regard as amongst the most effective on the market.

There is also considerable attention to detail in the serviceability of the DL series wheel loaders. Greasing can be done at standing height, and where a greasing point is in a location that is difficult to reach, a line is run to a more accessible location. Remote drain valves have been installed for coolant and engine oil for easy external access at standing height, and external sight gauges facilitate ready daily checking of hydraulic oil and radiator coolant levels. The oil filler pipe for the transmission is also readily accessible, near the articulation joint. Pressure check points for all hydraulic circuits (including the pilot circuit) and for transmission clutch pressures are grouped in a central location for ready access.

There is also a plug in the cab for connecting a laptop computer to diagnose engine and transmission faults.

The brake system exhibits considerable attention to detail. The brake discs are positioned to the rear of the reduction gear, and attention has been paid to oil flow in the hub and differential, to minimise heat build-up and extend the disc life. A disc clearance regulator maintains clearance as the disc wears, preserving braking performance. Disc wear can be monitored without disturbing the hub.

The drivetrain of the Doosan wheel loaders is also impressive, with standard equipment limited slip differentials on both front and rear for excellent traction in difficult conditions. ZF gearboxes are specified and can be operated in one of three modes: manual, fully automatic or automatic with a kickdown option.

PUT TO THE TEST
The Doosan distributor in Australia, Clark Equipment, is confident that wherever objective and unbiased trials are conducted with comparable specification machines of other brands, the Doosan wheel loader will acquit itself well on performance, reliability, and fuel economy. It already has a number of examples to back this opinion.

Boral Quarries
Boral selected eight brands of wheel loader to take place in trials at its Deer Park quarry, as part of a selection process for future sales loader requirements. Each loader was trialled for a two week period, with input sought from multiple staff on a broad range of criteria.

Clark Equipment supplied a 4.5m3 DL450 for trial (its 5m3 DL500 being unavailable in time for initial trials). While the bucket size was smaller than was ideal for the application, Boral compensated for this by working the machine in dense material so that it handled similar weights to other machines evaluated in the tests.

The trials involved loading between 2500 and 3000 tonnes per day, with this being shuttle work between stockpiles and road trucks during loading, and empty travel between stockpiles for loading different specifications of material. As such this was a test of the ability to crowd into a stockpile to fill the bucket, and the speed of direction changes and acceleration with a load, but it did not place great demands on the ride control.

Despite having a smaller bucket than other machines in the trial, the Doosan DL450 wheel loader moved similar weights of aggregate to other machines and its fuel economy was amongst the best of the machines in the trial.

Deer Park quarry manager Cameron McIntosh admitted that he did not have previous experience of the brand and he did not have high expectations going into the trials. However, Cameron and the others involved in the trial kept an open mind and allowed each machine to be judged on its merits. Operators overcame their initial wariness of a brand they were unfamiliar with, and came away very impressed with the performance, stability and comfort of the DL450.

Cameron McIntosh was happy with how the Doosan was presented for the trial, with good tyres and pressures appropriate for the conditions, and was impressed with its performance during the trials. He noted that designers of the DL series wheel loaders appeared to have looked at what worked well in other machines and implemented some of the best aspects of those features in their design.

Tweed Shire Council
The Tweed Shire Council in northern New South Wales also conducted trials when looking for a new loader to work at its quarry at Eviron. While the quarry has been established for some time, the council is looking to expand its size in preparation for future conversion to a landfill for Tweed Shire Waste Management.

A Doosan DL300 wheel loader is currently owned and operated by the council, but the expansion of the quarry has seen the need for a larger machine. Until environmental approvals are in place for the sites earmarked for the landfill expansion, machines of various brands will be hired and operated in the quarry to evaluate the best machine to purchase.

The quarry produces a decorative aggregate known as Tweed cream, as well as CBR80 and CBR45 roadbase materials and cracker dust. Aggregate is produced in sizes ranging from a -7mm to 70mm+ dust. The decorative aggregate has found a substantial commercial market in southeast Queensland and northern NSW, but this market is expected to continue to grow and account for much of the increased production from the quarry.

However, there are a number of special considerations in extracting the rock, and these impact on the extraction methods and choice of equipment. The rock has a high silica content, which causes accelerated wear of cutting edges, screens and the like. As a result, blasts are designed to achieve high rock fragmentation and thus reduce the crushing requirements, and consequent wear.

The material also has a high clay content, which causes significant loss of material in heavy rain if the shot material is left on the quarry floor. Since the Tweed Valley is in a high rainfall area, there is a need for the quarry loader to quickly build stockpiles after a blast to minimise material loss.

Other duties of the quarry loader include shuttling material from the stockpiles to crushing and screening equipment and loading road trucks. These duties test a number of areas of wheel loader performance.

The power and traction of the Doosan DL400 is important in building stockpiles, and the only limiting factor in climbing a stockpile with a full bucket is when the counterweight bottoms, although grade ability is limited to 58 per cent.

Ride control comes into play when shuttling material from the blast area to the stockpile, and from the stockpile to the crushing and screening equipment. The operator regards the Doosan’s ride control as amongst the best on the market, with the comfort and ride quality allowing him to have one hand on the steering wheel and the other on the loader joystick during operation.

Once all machines had been trialled at Eviron quarry, two machines stood out as front runners: a well known brand and the Doosan DL400. While a DL450 was the appropriate competitor to the well known brand, the DL400 satisfied the requirement. Criteria such as ride quality, cabin comfort, reliability and productivity let down other brands in the trial and the well known brand and Doosan machines were at or near the top of all critical evaluation criteria. Another area where the Doosan loader stood out was in its low brake wear, as some loaders in the trial experienced significant problems in this area in the abrasive conditions.

THE BACK-UP BEHIND THE LOADER
Downer EDI Works Infrastructure is another business that chose a Doosan wheel loader after evaluating other machines, and this machine has been acquired and maintained on a maintenance contract with Clark Equipment, a BRW Top 500 private company operating from over 20 locations across Australia and New Zealand and employing over 450 people.

The ability to support the machine, particularly during night work that is common in the asphalt industry, was an important factor in Downer EDI Works Infrastructure’s decision to opt for the Doosan machine. While the company is familiar with Clark Equipment’s ability to support the product it supplies, such as paving equipment to Downer EDI, most in the quarry and general construction industry associate Clark Equipment with Bobcat skid steer loaders and mini-excavators.

While this is acknowledgment of Clark Equipment’s success with the Bobcat brand in Australia, it does not do full justice to Clark Equipment’s ability to support large earthmoving and other equipment.

It is little known in the quarry and construction industry that Clark Equipment designs and builds Omega reach stackers and Omega container forklifts for port and container terminal operation and exports these around the world. It also supports the Omega equipment in Australia, along with the Noell straddle carriers and Terberg terminal tractors for which it is the Australian distributor. With Clark Equipment being a market leader in container handling equipment and with reliability and productivity being an important part of operating a successful container terminal in an around the clock operation, Clark Equipment has a heavy investment in back-up and support to provide a fast response regardless of the time of day.

With this structure in place, it is comparatively easy for the company to provide similar support for the Doosan loaders and excavators, Bobcat compact equipment, Terex and LeeBoy road equipment, Sakai compaction equipment and Champion graders that it also distributes in Australia.

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