Hauling the earth

According to the latest figures available from Off-Highway Research, the global market for articulated dump trucks (ADT) and rigid haulers stood at 7864 units in 2005, up from 6349 machines in 2004. Total sales for ADTs was 5758 worldwide, while sales of rigid dump trucks stood at 2106.

However, there are some interesting regional variations in the figures. For ADTs the most popular markets were Europe and the US, with sales of 1988 and 3700, respectively. Japan bought just 50 ADTs while China bought only 20. For rigid haulers the figures are a little closer. In 2005 the US had sales of 835 units, followed by Europe with 606, while China was close behind with sales on 515. However, the Japanese market bought only 150 units.

Off-Highway Research's managing director, David Philips predicts 2006 will see the market fall slightly to total sales of 7685, with sales of 534 rigid haulers in Europe being the root cause. However, Mr Philips told iC that sales of ADTs in China, Europe and North America should all rise, with sales of 70, 1990 and 3900 units, respectively, while sales in Japan should remain static on 50 units.

Sales of rigid haulers, said Mr Philips, should also rise. Mr Philips told iC he expects sales in China to reach 600 units, with the US and Japan taking 875 and 200 units, respectively.

New machines

One of the biggest drivers behind the launch of new construction equipment in recent months has been the introduction of new engine emission regulations. The first engines to be affected by the latest Tier 3/Stage IIIA regulations, which came into force in January this year, are those within the 130 and 560 kW powerband, which covers the majority of ADTs currently in production.

While the introduction of the new regulations resulted in a wave of new machine launches for other types of construction equipment a similar pattern has not emerged in the hauler sector. Caterpillar and Volvo, for example, added Tier 3 compliant engines to their machines last year, while Terex launched its new models in January.

According to Volvo Construction Equipment product manager Jonas Thoursie, the transition between Tier 2 and 3 powered machines is smoother for haulers than for other types of construction equipment. Mr Thoursie believes this is why there hasn't been a widespread launch of new models in the sector. “The specification of Volvo's V-ACT Tier 3 compliant engine, which is fitted in all five of our models, is very similar to the Tier 2 machines,” he said.

“The new engines have the same displacement as the old ones and the fuel economy is very similar. In other product lines the move from Tier 2 to 3 has been used as an opportunity to re-engineer the design. Some of the reengineering on other equipment may have been necessary because the Tier 2 engines used were significantly different to the Tier 3 units. The similarity between the engines used in our haulers, meant that a major upgrade was not needed.”

Cat's 23 tonne 725 and 28 tonne 730 are powered by 225 and 237 kW versions of its C11 ACERT engine. The other models in Cat's ADT range are the 32.7 tonne 735 and 38 tonne 740 have C15 ACERT engines, which produce 287 and 325 kW, respectively. Cat is launching several new rigid frame trucks this month, the 60 ton (54.5 tonne) capacity 773F, the 70 ton (63.6 tonne) capacity 775F and the 100 ton (90.9 tonne) capacity 777F. A detailed report on all these machines will appear in next months iC.

Terex unveiled new Tier 3 powered versions of its larger haulers in January. The company's 37.5 ton (34 tonne) payload TA35 and 40 ton (36.4 tonne) payload TA40 have been updated with the addition of new Detroit Diesel Series 60 Tier 3 compliant engines - 298 kW unit for the TA35 and 335 kW for the TA40.

The TA35 has a heaped capacity of 21 m³, while TA40 can carry up to 23 m³. Other improvements to the TA35 and TA40 include automatic limited slip differentials in each axle to add traction and a new front-end suspension system to provide a better ride. Engine oil change is now every 500 hours and the design features a ground level tilting cab to provide easier access. In the cab, the controls have been ergonomically redesigned with new instrument clusters.

Bell has also updated its D-series hauler range with new Tier 3 compliant engines from Mercedes Benz. According to Bell's head of design Peter Bell, the Mercedes engine needed very few changes in order to comply with Tier 3.

“The Tier 2 compliant Mercedes engine came very close to complying with the Tier 3 regulations,” he said. “Internally some of the piston geometry had to be changed and the turbo needed to be reconfigured. Because the difference is so minor we have been able to incorporate the new engines without the need for a complete redesign.

“Nonetheless, the compact design of the new engine did enable the front end to be redesigned with a shorter nose, which has reduced the deadweight of the machine,” added Mr Bell.

“The focus of our hauler range is on fuel efficiency. Converting fuel to work is a function of the machine's power and drive train efficiency, weight and rolling resistance. Getting all of these to combine to the best advantage has enabled us to achieve substantial fuel savings.” According to Mr Bell, the fuel burn to tonnes moved for Bell's trucks is up to -25% less than that of other manufacturers.

Moxy's latest ADT, the upgraded MT36 is now powered by a Tier 3 compliant 294 kW Scania engine which is a lower rated version of the 335 kW unit used in the MT41. The new MT36 can carry a maximum payload of 32.7 tonnes and has a heaped capacity of up to 21.5 m³.

The new model features independent front suspension, which allows for free movement on one side without movement on the opposite side to give maximum ground contact. Like the MT41, the MT36 will now be fitted with hydraulic multiple wet brakes as standard as well as electronically controlled automatic lubrication.

Volvo's range of D-Series ADTs may not have been re-launched following addition of the Tier 3 complaint V-ACT engine but are now also available with an Automatic Traction Control (ATC) system. According to Volvo the ATC system will reduce wear and improve fuel consumption. The system monitors wheel slippage and engages the 100% dog clutch locks when needed. This allows the hauler to get maximum drive when required but maximum drive is not used all the time.

According to Volvo, some less experienced operators leave their haulers in all wheel drive permanently even though conditions on site don't demand it. Over use of all wheel drive can result in increased fuel consumption, tyre wear and mechanical wear.

Acapulco bound

Moving earth and rocks is the staple diet of many ADTs around the world, and huge quantities too. In Mexico a fleet of JCB tracked excavators and ADTs is at the centre of a project to move over 3 million tonnes of earth and rock near Acapulco, paving the way for the construction of a major highway. Earthmoving contractor Tres Construyendo is using two JS330LC excavators and four 37.5 tonne capacity 722 ADTs during construction of a 20 km, 4-lane highway, 300 km south of Mexico City close to the country's famous Acapulco resort.

The nearest major city, Chilpancingo, the capital of Guerrero state, is about 1300 m above sea level. With the huge amount of material to be moved the JS330s and 722s are working in classic tandem mode to complete the task: excavate, load, transport. Each JS330 is excavating 3300 tonnes per day from the face, which is then loaded in to the 722s for transportation back to the main site. The 722s are performing short runs of roughly 300 m down steep inclines, unloading the material into a 150000mholding area, where it will be compacted for use as fill for the later stages of the road construction. Initially the six JCB machines are handling the workload, but as the loading requirements begin to intensify on the 18 month project, they will be joined by a further two 722's and two JCB 456 wheeled loading shovels. Key to the success of the machines in the region's tropical climate and arduous ground conditions has been their durability, off-road performance, fuel efficiency and service support.

Tres Construyendo project manager Jorge Castro said: “I have been extremely impressed with the productivity and fuel economy of all the machines, while JCB's dealer, Auriga, has stationed two engineers on site, giving us parts and back-up whenever we need them.”

Access roads

Elsewhere in Mexico, four new Terex TA40s are at work hauling dirt at the Ocampo gold mine, near Gammon Lake, one of the largest open pit gold-silver mines in Mexico. This mountainous project encompasses 3500 ha of untouched minerals and is owned and operated by Gammon Lake Resources, Nova Scotia, Canada. Due to the remote location and narrow access roads to the site the trucks had to be unloaded from their low loaders in the town of Basaseatchi in Northern Mexico and then driven 30 km through small towns and villages to reach the site.

Since arriving the trucks have begun to transport material for the access roads with each truck operating two 10-hour shifts per day. Depending on the haul route the TA40's cycle from 20 to 30 hauls per shift. The high net power of the new TA40 is particularly suited to this type of work, as at 326 kW the truck has good climbing capabilities, a “must have” when working on the steep gradients associated with this type of project. The new TA40s are fitted with Tier 3 compliant Detroit Diesel Engines, Allison Transmissions, ZF Axles and oil cooled disc brakes.

However, these are not the first Terex trucks at the site. The Ocampo currently has 17 TR100's and a TR100 chassis fitted with an 18000 litre Klein water tank for dust control, all of which were supplied by Terex's Mexican dealer, Ameco. The TR100's are working two 12 hour shifts per day moving overburden to allow access to the mineral seams. Similar to the ADT's operation, the haul cycles can vary from 0.5 to 1 km and the gradient can change dramatically. Thanks to its 703 kW Cummins KTA38 engine, which has a first overhaul interval of between 15000 and 20000 hours, the 100 ton (90.9 tonne) rigid frame TR100's traction is proving ideal in the soft conditions on the remote Ocampo site.

As with the Chilpancingo road project after sales support has proved vital in maintaining the fleet. Due to the size and remote location of Ocampo, Terex has provided an on-site support team and training programme: the technicians and trainers will be onsite for 12 months.

Outlook

The introduction of new engine emission regulations in January this year mean many hauler manufacturers will continue to launch new machines in the coming months. Bauma China in November this year, and Bauma Germany in April 2007, therefore, should be the first chance to see many of these new machines. The drive towards cleaner, more powerful machines capable of delivering increased productivity, while reducing service and maintenance requirements, is also bound to push future development too. While the continued infrastructure investments in China, the US, the Middle East and Eastern Europe should also continue to bolster global sales.