CONVEYING
NO PROBLEM WITH THE CURVE: RAIL RUNNING CONVEYOR SOLUTIONS
Larger quarries are increasingly looking for economical solutions to transporting aggregates from the face to the crushing circuit. A proposed curved rail running conveyor may yet provide an alternative to conventional transport by dump trucks and off-road vehicles.
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nnovative operators in the quarrying business are constantly adapting to overcome the lean operating margins and environmental constraints at their sites. Now a new conveying technology from thyssenkrupp and the University of Newcastle relieves familiar challenges faced by larger quarry operations, including: • Costly truck haulage from the face to the plant, especially where there is substantial elevation change. • Concerns about diesel and dust emissions. • Fugitive dust from conveyor transfer points. • Mine layouts that are awkward or unfeasible for conventional trough conveyors. This new belt conveying technology allows a conveyor to run in a single flight from pit to plant along the curve of the haul road, hairpins excepted. For many pit layouts where the haul road curve radii can be configured to about 100m or greater, mines will be able to run haul trucks adjacent to the conveying corridor, allowing for the flexibility of truck haulage alongside the extremely low cost per tonne of belt conveying. The payback time for replacing the truck haulage by the curved conveyor can be less than a year in some cases, according to estimates by thyssenkrupp. Those estimates include the operating cost of feeding the conveyor from a mobile primary crusher sizing down to perhaps minus 200mm.
RAIL RUNNING CONVEYOR This new type of curved conveyor is a “pipe conveyor” version of the “Rail Running Conveyor” (or RRC) technology now being commercialised in Australia under an exclusive agreement between thyssenkrupp and the University of Newcastle. The product is part of a new “platform technology” that combines the efficiency of rail transport with the continuous nature of belt conveying, and 20
Quarry May 2020
A concept image of the thyssenkrupp/University of Newcastle Rail Running Conveyor.
promises a “revolution” in overland, steep angle and pipe conveying, according to Luke Bennett, the national sales manager for strategic accounts at thyssenkrupp Industrial Solutions Australia. The pipe conveyor version of the system is now ready to be deployed in a pilot installation at a quarry, ideally carrying the full output from a large tracked jaw crusher for a distance of up to one kilometre or through an elevation change of 50m to 100m. For this technology, testing and analysis point to: • Capital expenditure (CAPEX) being about the same as a conventional trough conveyor of similar length, lift and tonnage, and less than half of that for a conventional pipe conveyor in the same duty. • Power consumption being about 40 per cent lower than a conventional pipe conveyor, even though most of the power requirement for the example above is needed for lifting the rock. • Lower maintenance costs, because the transport mode eliminates almost all of the maintenance effort associated with the
idlers, belt tracking and carry-back. For some mine layouts, a planner might be considering costly trough conveyors on an elevated structure, such as that visible in the Google Earth image of a haulage route in a large limestone quarry (Figure 1). Due to the Rail Running Conveyor’s ability to negotiate very tight curves, the material could be carried by either trough or pipe RRC versions along the haul road, on a path indicated by the blue line. Even though the length of the RRC is greater than the direct, elevated route, the CAPEX cost per metre as well as the much lower maintenance intensity makes the curved RRC the lowest cost choice by far. The RRC technology has been carefully developed over nearly a decade by TUNRA Bulk Solids at the University of Newcastle, and is covered by a number of international patents. Contemporaneously, thyssenkrupp’s heavy duty conveyor group created designs based on similar principles, and now the University of Newcastle and thyssenkrupp are collaborating to bring this product family to the industrial minerals industry. To put this technology in context, it is
