Sandvik Mining and Construction has released two new Tier 3 compliant underground coal loaders, the 7tn LS171 and the 10tn LS191. The company has already delivered the first units to Narrabri Coal. Both loaders are powered by a low-emission Tier 3 Caterpillar C7 engine through a Sandvik specified electronic engine management system specifically designed for underground applications. The Cat C7 ACERT engine delivers gross power of 172kW at 2200rpm and maximum torque of 940Nm at 1650rpm giving greater tractive effort and increased towing performance. Both the LS171 and LS191 loaders share a high degree of parts and components commonality, including the engine electronics and some drivetrain components, with the main difference being in the hydraulics systems of the two machines. The LS171 uses a conventional fixed displacement hydraulic system for its loader system, while at the same time incorporating upgraded pumps. The LS191 as with its predecessor the LS190 has a pressure compensating hydraulic system which allows it to act as a prime mover unit for Sandvik’s 50tn hydraulic drive roof support trailer, used for relocating longwall shields and equipment. This pressure compensating hydraulic system allows the LS191 to efficiently deliver hydraulic power to drive the trailer, for faster, more effective moving of large longwall components. An upgraded hydraulic system features new, more efficient pumps to allow a reduction in engine speed 2300rpm compared with 2600rpm for its predecessor resulting in lower noise levels.
