Coal Age

NOV 2015

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After the Bucyrus acquisition in 2011, Caterpillar identified an opportunity to provide an option for customers who sought 320- ton-capacity trucks. "We still believe that, in many applications, the 250-ton- capacity Cat 793 truck still delivers the best cost per ton, but some customers have asked for a 320-ton option," Singh said. Singh worked with Unit Rig, which was acquired by Bucyrus when it bought the Terex mining business in 2010. When Cat acquired Bucyrus in 2011, he transitioned from Milwaukee to Decatur. In 2012, Cat launched the 320-ton Unit Rig MT5300. "We have been testing it since early 2013," Singh said. "We have demonstrated a very competitive cost per ton in studies at two different mine sites." Cat will commercially launch the 5300 in 2016 as the 794 AC. The new Cat nomenclature identifies the truck as sized between the 793 and the 795. "We are launching it in a controlled way at targeted sites as a 320-ton Cat 794 AC mining truck," Singh said. The new truck is Caterpillar designed and fully integrated in the company's manufacturing and product support system. The truck is manufactured in Decatur, where all Cat large mining trucks are built. "It has passed through the same quality and testing proce- dures as the other Cat trucks in Decatur," Singh said. In a lot of ways the new truck's design is similar to that of the 345-ton Cat 795F. "This gives the customer more confidence in the power train and engine performance," Singh said. "The 795 electric-drive power train now has more than 2.5 million hours. The individual highest hours for the 795 is more than 35,000 hours. We are pleased with the feedback we are getting from min- ers. Some 795's have achieved more than 8,000 hours operating time in a single calendar year. The 794 leverages all of the positive benefits of the 795 has brought into the Cat network." Cat has made a significant investment to give customers more options in the 320-ton size class. For those miners looking to improve existing fleets, Cat is now providing retrofit kits for some technologies and improvements found on the newer trucks, such as extended brake-life materials, LED light kits and several safety features including one for work- ing at height. "The working-at-height retrofit kits allow the min- ers to install tie off points on the truck," Singh said. "These tie-off points have become especially popular with mechanics working on the 400-ton Cat 797s in Canada." An improved fuel map feature for haul trucks lets miners use the engine and power train software to determine optimum fuel consumption in a given haul cycle. "We have been able to work with miners to improve fuel consumption by 6% to 12%," Singh said. "Fuel represents 30% to 60% of mining costs for open-pit mines." Cat is also investing in LNG technology for haul trucks. The company said it has successfully demonstrated the benefits they were targeting on a prototype at its proving grounds in Tucson, Arizona. Fully Integrated Hitachi Technology During the summer, Hitachi also added electric drive options for its haul truck customer with two new models, the 200-ton EH3500AC-3 and the 240-ton EH4000AC-3. Both trucks are equipped with an advanced AC-drive system that was developed by Hitachi. The company said it coupled the AC-drive system, which has a high load-responsive IGBT inverter, with drive-con- trol software to better control travel motor speed and torque. Whether taking off from a standstill, ascending grades or per- forming steering maneuvers, Hitachi claims the system delivers an optimal, individual amount of power to each of the travel motors for smooth operation. The Hitachi drive control system aims to achieve higher drive control performance by reducing tire slippage on acceleration and tire lockup during braking and preventing chassis oscillation in a front-rear direction and tire skid while steering. Consequently, the trucks boast strong and steady travel perfor- mance that ensures more stable haul cycle times, which will con- tribute to higher productivity, according to the company. "This is a fully integrated truck from the drive to the frame," Mace said. "We do not need to rely on another company's tech- nology. The slippage control on these AC-3 units prevents over- steering or drifting. The drive controls the pitch eliminating that rebounding effect from an oscillating chassis. The anti-skid fea- ture prevents over-steering on turns." These two new AC-3 models also feature electric brakes that are activated during downhill driving. Since these trucks do not require the use of mechanical brakes during normal driving, not only is deceleration smoother, but maintenance for the mechani- cal brakes is required less frequently. "Both of these size classes — 200 tons and 240 tons — are quite popular with coal operators," Mace said. "For the EH3500AC-3, we were able to increase the capacity to get to the 200-ton nominal payload class. The previous model was a little smaller. We had a couple of these trucks operating at central Appalachian operations. We also have several AC trucks working in Colombia." Hitachi has not overlooked safety. At MINExpo 2012, the com- pany introduced the SkyAngle feature that gives the operator 360° h a u l t r u c k s c o n t i n u e d November 2015 www.coalage.com 35 Hitachi recently introduced the 240-ton EH4000AC-3.

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