The Asia Miner

APR-JUN 2019

The ASIA Miner - Reporting Important Issues to Mining Companies in the Asia Pacific Region

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Mining VDMA 49 2019 • VDMA MINING SUPPLEMENT can do the same job with three 400 kW as four 250 kW on the base frames. With the bigger pumps, we are moving more liquid per pump so the system have to be engineered accordingly." An unloader valve is used to dump pressure off the face to compensate for traditional drive systems. While the unloader valve is still present, the VFDs dramatically improve system performance. "We were the first to use VFDs with the emulsion pumps in Germany in 2002," Wahl said. "With the VFDs, the speed of pumps can be adjusted to the demand from the face. The system still uses the master and slave pump configuration. When the master reaches maximum speed, the slave pumps are brought online grad- ually to meet the pressure requirements of the face. From an engineering perspective, this is state-of-the-art, much less wear, it's a smooth, intelligent and elegant system." The VFDs allow a very wide range of speed adjustment from 100% down to 20% of nominal speed. One pump can pump 800 liters per minute (l/min) down to 160 l/min. When the longwall face needs 120%, the Kamat system allows one pump to run at full capacity while another runs at 20%. Other systems use two pumps running at 60%, which means they need to use two VFDs, which increases costs significantly." A VFD for the 1.1-KVA system will cost approximately $150,000. At 3.3 KVA, the price climbs to nearly $500,000. That explains why these systems are so popular in China and the U.S., and not so much in Austra- lia. Australian coal operators use a 3.3-KVA power supply, which makes the use of VFDs cost prohibitive. System designs differ by region. "The classic U.S. system is a plat- form with pumps and tanks, but the Australian systems have screens monitoring everything," Wahl said. "Obviously, they could get by without it, but the Australian coal operators love it, so they have it. In the U.S., it's a much simpler system and they say put as many pumps as you can on the platform. In China and Russia, it looks more like a train, individual units chained together." As far as service and support, Kamat partners with regional firms, such as Morgantown Machine & Hydraulics, a subsidiary of Swanson Industries in the U.S., and Longwall Hydraulics in Australia. "Swanson has a great workshop and they can perform all sorts of services includ- ing major surgery on the pumps," Wahl said. "In general, our customers are able to do the standard service at the pumps even in China. These pumps are very easy to service. They don't need to remove the head. They can change the valves, the plunger, the packing and seals with the pump in place. For a halfway good fitter, it's a 1-hour job to replace valves and pistons." The pumps require some standard service. "The pistons last a long time, but the seals start to leak after so many hours depending on operat- ing conditions and the quality of the fluids," Wahl said. "When the mines move the longwall, they perform more in-depth service. That's when they bring the whole platform into Swanson's shop. Swanson would replace a crankshaft and that's something we wouldn't expect the miners to do." Seeing the role that Kamat has played in the steady improvement in longwall operations, Wahl believes longwall operators will continue the transition to bigger pumps and the use of VFD technology. Underground Utility Vehicles Every successful underground mining operation is supported by a host of utility vehicles. Located in Emsbüren, Germany, Hermann Paus Maschin- enfabrik GmbH has been supplying utility support equipment for more than 50 years now. The company's MinCa series features two basic models, the MinCa 18 and the MinCa 5.1. The vehicles are extremely versatile and can Operatio nal Excellence Training. RWE Technology International (RWETI) tailors Operation Excellence (OpEx) training programs adapted to customer specific needs, covering technical, economical and/or administrative aspects of mine and power plant operations. Training Programs and Insights: - Mine & Power Plant Management and Planning - Plant Operation & Maintenance - QHSE Best Practice - Best-practice exchange with RWE peers - Technical Training, Workshop, Seminar, Webinar - Mentoring / Shadowing Benefit from the vast operational knowledge of RWE, a leading Utility with a 120-year history shaping the mining and power industry of Europe. T +49 221 480-1303 E re@rwe.com I www.rweti.com RWE mine training session: conveyor belt shifting in an open pit mine ( 2018 ) Powering. Reliable. Future.

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