Capital Equipment News

With an apparent growth of the 100 t rigid hauler market – mainly driven by demand from the contract mining fraternity – Liebherr Africa is entering this market segment for the first time following the arrival of its first T236 rigid hauler, said to be the first diesel-electric truck in this size class, writes Munesu Shoko.

Following the completion of field operation trials at Austria’s largest iron ore mine, Erzberg, the first Liebherr T236 rigid hauler has arrived in South Africa. This is part of the pre-series units being rolled out to selected operations across the world to further validate the truck’s capabilities before its commercial launch. Liebherr Africa intends to deploy the truck to work at a leading Northern Cape mine. 

Liebherr into new terrain

Tom Munch, Director Mining, says the new 100 t offering arrives at an opportune time for Liebherr Africa. “We are working in a contract mining market. If you look at the type of equipment this group of customers requires currently, it’s mainly 100 t excavators and 100 t dump trucks. This is due to the mobility they require, given that their contracts are limited to 3-5 years at most,” says Munch.

Munch adds that Liebherr also urgently needed a truck to complement its excavator range. Designed to carry up to 100 metric tonnes of payload, the T236 can be ideally paired with Liebherr’s R 9100, R 9150, R 9200 or R 9250 mining excavators.

Munch reasons that the T236 is ideally suited for the contract mining market because it speaks directly to lower cost per ton, increased productivity and safety, three key parameters of sheer significance to mining contractors, especially in light of the current tight operating conditions.

Mining companies have spent many years ruthlessly seeking ways to reduce their operating costs. One of the measures they have implemented is supply chain optimisation. In a bid to control their costs, many miners have tightened their contractor service level agreements. For example, many mines have put a fuel cap on each and every contractor’s machine. If a machine exceeds its fuel cap, the extra fuel consumption will be deducted off the mining contractor’s certificate.

Donald Hewitt, National Service Manager – Mining at Liebherr Africa, says probably 60-70% of mining contracts awarded today have a fuel cap. Previously, “wet contracts” had no limit on fuel and contractors were not so concerned by the fuel efficiency of their machines. Today, mining contractors are being forced to rank fuel consumption high up on their buying checklists. With a range of fuel-saving innovations, the T236 will surely address these woes.  

Lower cost per ton

Abie Kriel, Technical Manager – Mining at Liebherr Africa, says the T236 sets a new era by becoming the first truck in the 100 t segment to utilise a diesel-electric drive system. A major talking point is Liebherr’s Litronic Plus Generation 2 drive system, which introduces the advanced Active Front End technology. Making use of electrical energy during retarding events, the drive system is able to deliver controlled engine speed, controlled decent speeds via speed control and active braking.

“The Active Front End control and electric drive work in harmony to use less fuel and cause less wear on components, translating into greater cost-savings,” says Kriel. “As the first diesel-electric truck in the 100 t class to incorporate an oil immersed braking system with four-corner braking control, the T 236 is geared to deliver sound reliability and performance, even in tough operating conditions.”

Christopher Vorster, National Sales Manager – Mining at Liebherr Africa, says with its high take-off torque and continuous power-to-ground capability, the T 236 is less sensitive to grade and payload variations, resulting in greater productivity.

Vertical integration of Liebherr designed and manufactured components ensures that the truck’s powertrain achieves optimal system efficiency and performance throughout the full range of applications. The truck’s innovative, variable hydraulic system lowers machine parasitic losses to provide maximum power, while lowering fuel consumption when power is not required.

“Powered by a Cummins QST30-C engine, the T264 reduces fuel consumption due to its low parasitic powertrain losses. Optimised energy consumption during propulsion ensures the Liebherr T236 makes efficient use of constant engine power, providing the lowest possible fuel consumption,” explains Vorster. “Efficiency is a key ingredient for a successful mining operation. This truck enables customers to enjoy unrivalled performance while reducing cost per ton.”

“During retard, the power generated by the wheels is used to increase parasitic energy consumption and reduce truck speed by engine friction, while controlling the engine speed anytime,” says Hewitt.

More benefits abound

Apart from being the only mining truck with a diesel electric drive system in the 100-t class, Munch says the T236 also sets a new era in this class size with its 100 t payload. Many of the competitive trucks in this category achieve about 92 t of payload, while the T236 loads a maximum 100 t payload, translating into 8% more payload. This improves productivity, while lowering cost per ton.

This is achieved through the truck’s clever design. Its front suspension has the same width as the rear outside wheels’ suspension. This means that the truck has a more or less square track pattern, which makes it very stable, even when it has to turn or brake on a decline where, in most instances, tyres collapse. “We run a double-wishbone suspension, which reduces the ‘Ackerman error’, meaning you have got less tyre deformation during turns,” explains Hewitt. “The intelligent design allows the T236 to move more tonnes per hour by maximising payload and reducing cycle times.”

Munch says one of the most interesting aspects about the diesel-electric system is the elimination of mechanical components. These are subject to normal wear and tear and will require periodic maintenance and exchange. A considerable amount of time and money can be saved compared with a conventional mechanically-driven truck. That simultaneously drives down operational costs due to less maintenance.

“Mechanically-driven trucks require more maintenance through oil changes, while service life of major components is shorter compared with electric drive systems,” reasons Munch. “The electric drive has fewer major components than the mechanical drive option, and this translates into less potential failures. Fewer components also mean less maintenance, which in turn translates into higher availability and ultimately higher productivity.”

Liebherr has also incorporated an array of new technologies to provide customers with a high quality rigid hauler. The T236’s Advanced Traction Control System is said to have been developed exclusively for mining truck applications. With four-wheel speed sensing capability, torque is automatically adjusted to the rear wheels to maximise traction when cornering, accelerating from a standstill position, or travelling down wet or icy roads. An anti-rollback feature is standard on the T236.

Meanwhile, the in-line electrical powertrain layout minimises cable lengths, while the maintenance-free IP-68 rated plug-and-drive power modules ensure reliable operation in all weather conditions.

Safety and serviceability

To ensure maximum safety for maintenance technicians, the T236 is equipped with a double pole battery, starter motor and hoist system isolators as standard. In addition, it comes with an innovative drive system inhibiter, electrically interlocked grounding devices for each plug and drive power module.

For easy service access, the alternator is remote mounted and connected to the splitter box with a drive shaft. The electrical control cabinets of the drive are in maintenance-free segregated modules, ensuring protection in the tough mining environment. The power modules only control the drive, operating with 600 Volts AC and 900 Volts on the DC link to remain in a class of low tension, while all auxiliary systems are hydraulically driven – allowing regular site electricians to work on the system.

An additional benefit of the external power module grounding system in the powertrain and positive drive isolation is that it allows work to be done on the machine while the engine is running.

“Safety features in the truck’s cab, such as dual-side access and incorporation of ROPS comparable to a 150 t class truck, were engineered during the initial design process, while a recessed, full-size trainer seat allows for increased visibility,” concludes Kriel.

“By effective use of electrical energy during retarding events, the drive system is able to deliver controlled engine speed with almost no fuel consumption. Engine over speed events are eliminated during retard events by actively using the four-corner braking and active speed control.”

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