VDMA

Germany 2019

Best of Germany 2014 - Mining Equipment and Mining Technology

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VDMA 25 2019 • VDMA MINING SUPPLEMENT Cat abandoned the room-and-pillar segment for coal operators a few years ago. Gainwell uses other suppliers for shuttle cars, roof bolters and feeder-breakers. The machine that will be installed at the PVK-5 mine will be a CM2H-45, Lange explained, which means it was originally designed for a coal cutting height of 4.5 m. "This is Eickhoff's first continuous miner in India and there are currently 14 continuous miners operat- ing in the country," Lange said. "The potential project list is huge." Working in cooperation with Gainwell, Eickhoff will make sure this project kicks off successfully, Lange explained. "This involves the training of Gainwell's personnel," Lange said. "There will be in- tensive training in Germany and India to reinforce the experience of Gainwell's international team regarding Eickhoff technology." PVK-5 is a half-developed incline mine. It was placed on care and maintenance and Singareni is now planning to restart it toward the end of this year. At one time it was a conventional mine using drilling-and-blasting techniques. Gainwell will have to widen the roads and remove a lot of the remaining coal in the process. They will be mining from two seams, the King and Queen seams. "We were in the King seam and we saw the areas where the previous operators took 2.5 m of the 5 m seam height," Lange said. "Gainwell will remove that bottom coal and then advance into an upper seam section. Once they mine and depillar that area, they will move back into the lower seam ultimately with depillaring operations there, too." Coal India Ltd. recently achieved a national record in coal pro- duction after Gainwell deployed continuous miners at its Jhanjra Project. During December 2014, the operation set a record produc- tion of 74,505 mt/month. This was the highest recorded production from a single Indian underground mine in development until the same operation produced 78,850 mt/month during depillaring oper- ations for March 2017. The continuous miner section at the Jhanjra project produced 5,050 mt/d of coal — highest ever single day pro- duction from a continuous miner section in India. "We are onboard with a partner who knows the business," Lange said. The Gainwell sale could certainly lead to more Indian opportu- nities for Eickhoff. The company, however, is not only interested in selling machines. They are committed to successful coal operations with backup support from Germany. Super-sizing Longwall Hydraulics Longwall mining operations rely on high-pressure pumps to deliver the hydraulic power needed to support and advance the face. As these mines extend the length and height of the faces, the pressures that must be maintained only increase. At the same time, autonomous operations are pushing the mining system to move the shields more quickly. This re- sponsiveness further increases the demand on hydraulic systems. Kamat's high-pressure pumps supply the pressure and flow that these systems now demand. The pumps have won high levels of accep- tance throughout all the major underground coal production regions because of their dependability, availability and ease of maintenance. Business has been brisk for Kamat. Explaining that Kamat also sells supply pumps to parallel industries, such as fracking and steel descaling, Dr. Andreas Wahl, managing director for Kamat, said that the mining business contributed considerably to the company's suc- cess last year. "We saw activity pick up in the U.S. and Australia, and China came back in a big way," Wahl said. "The demand from China is inconsistent. We saw Chinese demand for pumps grow last year and all signs are indicating that Chinese demand could be good again in 2019, but no one knows what will happen after 2019." Similar to other mining suppliers, Wahl wonders what will hap- pen with global trade tensions. Some countries are encouraging the mines to buy domestically, but they cannot replicate German crafts- manship, he explained. Kamat sees the longwall mining business moving toward bigger pumps with higher power inputs. The standard pump for the mining business 20 years ago was a 250-kW system. Then the mines ad- vanced to 350 kW and today Kamat is selling 500-kW pumps to the mines. They have an 800-kW pump, but no mines are using that yet. "This transition has a clear advantage for the end user because the entire system is less complex with less pumps and parts and it runs parallel to a general power input increase for the hydraulic sys- tems we are building," Wahl said. "The systems are getting bigger and bigger, especially in Australia, China and the U.S." In combination with these larger pumps, Kamat is incorporating more variable frequency drive (VFD) technology. "With our specially developed frequency-converter control, our plunger pumps can be driven between 20% and 100% rotation speed," Wahl said. "We have designed the gearing and other components to withstand op- erations at low rotation speeds." The standard Kamat system for longwall mining applications has a 2-MW power input with four base frames with pumps and valves and two tanks. "With the dust suppression component, we 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 com- pensate 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 gradually to meet the pressure require- ments 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 Kamat's K50000M-5G shown with motor mounted to a base frame is very popular with longwall mine operators.

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