Coal Age Magazine - For more than 100 years, Coal Age has been the magazine that readers can trust for guidance and insight on this important industry.
Issue link: https://coal.epubxp.com/i/640014
include a large crawler tractor, the compa- ny's first in the 70-mt category, and a newly developed 200-mt excavator. T h e R 9 2 0 0 e x c a v a t o r w a s b u i l t t o complement Liebherr's broad range of mining-class excavators. Equipped with a 1 2 . 5 - m 3 b u c k e t , t h e c o m p a n y s a i d i t o f f e r s s u s t a i n a b l e p e r f o r m a n c e w h i l e delivering peak fuel burn efficiency, even in the most challenging conditions. The excavator is a pass match for 140-mt haul trucks. The R 9200 is available in backhoe and face shovel configurations and is fitted with the company's advanced bucket and ground engaging tools (GET). The bucket has been engineered to deliver superior digging performance and high fill factors, according to Liebherr. It is powered by the Cummins QSK38 diesel engine that has a rated output of 810 kW. The cut- ting-edge cab of the R 9200 provides the operator with a panoramic view of their operation. The R 9200 integrates an advanced electronic piloting control sys- tem, which is both intuitive and versatile. Liebherr will also unveil the new PR776 crawler tractor, which is powered by a Liebherr 12-cylinder diesel engine develop- ing 565 kW (768 hp). The dozer has a maxi- mum operating weight of 74 mt and is equipped with blade capacities of 18 m 3 (semi-U blade) or 22 m 3 (U blade). The modern drive concept of the new PR 776 offers extremely efficient and safe operation to customers. A new feature in this machine class is the infinitely variable hydrostatic travel drive. Another advantage of the modern drive concept is the opti- mization of pressure flow. Hydraulic servo pressure is based on-demand according to the task. If, for example, the full feed of pres- sure supply is not required when operating, this is automatically returned. An engine management system com- bined with a power efficiency system and the hydrostatic driveline allows the PR 776 to maintain constant engine speed, increase overall machine efficiency and reduce fuel consumption. This differentiates Liebherr's travel drive concept from other drive concepts available on the market, where the engine speed fluctuates sharply during operation. Sizers for Crushing Coal For miners on the soft rock side of the busi- ness, thyssenkrupp will also display its RollSizer DRS 660X3000 S. Tailored to meet the requirements of the coal industry, the unit is also capable of crushing medium-hard rock as well as sticky and soft material. The com- plete series has recently been standardized and further models have been added. As a result, the entire range of applications, from primary to tertiary crushing of coal, can now be handled by thyssenkrupp RollSizers. With a roll length of 3 m and shaft cen- ter distance of 660 mm, the RollSizer DRS 660X3000 S is the second largest member of the family of secondary and tertiary RollSizers from thyssenkrupp. The model is designed as a SideSizer. Its rolls rotate outwards in opposite directions and crushing takes place between the rolls and the end walls of the housing. This is key to the crusher's extremely high throughput rates, clearly defined final product, and very compact design. The unit is fitted with exchangeable crusher segments made of wear-resistant steel which are durable and also quick and easy to replace. In addition, all sections of the housing that come into contact with the material during crushing are lined with wear plates. This maximizes the service life of the overall machine and minimizes maintenance requirements. The crushing combs arranged laterally on the end walls are available in various designs. Both the crushing combs and the end wall plating are horizontally adjustable so that product particle size can be precisely adjusted in line with requirements. The DRS 660X3000 S operates with an extremely robust direct drive system con- sisting of two spur gears with fluid cou- plings. The couplings allow startup of the sizer even under the load of a full crushing chamber and at the same time provide overload protection. In the presence of a foreign body, the slip of the fluid couplings protects the machine against damage. The required drive torque is provided by two powerful 250-kW electric motors. To ensure maximum operating safety, all thyssenkrupp RollSizers are fitted with sen- sors for monitoring the main machine parameters such as drive speed, bearing temperature and lubrication. New Bucketwheel for Harder Formations For the open-pit mining side of the business, thyssekrupp will present a new generation of compact bucketwheel excavators (BWEs): the Barracuda and the Mine Shark. Both machines will be able to work in hard materi- als with compressive strengths up to 50 MPa. While BWEs today mostly work in soft and medium-hard rock with a compressive strength of up to 20 MPa, this machine has been designed to work in a broad range of materials including coal, limestone, phos- phate rock, potash, frozen materials in win- ter conditions as well as in its corresponding overburden layers. To fulfill the requirements of the severe working conditions, special bucket and tooth designs have been applied by thyssenkrupp. These designs are based on b a u m a p r e v i e w c o n t i n u e d February 2016 www.coalage.com 25 The Liebherr PR 776 crawler tractor features a hydrostatic drive. T he thyssenkrupp RollSizer DRS 660X3000 S.