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34 www.coalage.com May 2017 plow mining High Performance Remote-Controlled Plow Systems Longwall systems that employ plows have evolved and today represent an attractive alternative for automated mining especially with low seams by michael myszkowski, ph.d. Nowadays technically efficient and eco- nomically viable underground mining systems play a more and more important role worldwide. Longwall mining sys- tems present the most effective extraction method, capable of annually producing several million tons from a single mining system. The extraction of thick seams is fully occupied by shearers, which work effectively even under difficult geological conditions. In thin seams, however, plows deliver the highest efficiency. Contemporary plow systems are de- signed to extract seams with a thickness below 3 ft to 6 ft, sometimes up to 10 ft (Ibbenbueren mine in Germany), and they stay in the seam without cutting the ad- joining rock in the roof or floor. Modern plow systems are remotely controlled ei- ther from an entry or from the surface. Due to the principle of operation, remote-con- trol capability, sophisticated power supply, and unique level of automation, the plow systems are capable of working very effi- ciently and safely. This article reviews some important high-performance plow appli- cations worldwide and discusses the future developments for this mining method. The Evolution of Plow Technology The plow technology for extraction of coal seams has been developed over 70 years in Germany. The first plow was tested at the Ibbenbueren mine in western Ger- many around 1940. Since that time, more than 10,000 plow faces have been installed worldwide. The peak number of plow fac- es occurred in the mid-1960s, where in Germany alone more than 500 plow faces were operating with an average produc- tion of 550 tons per day (tpd). Since then, the average performance has increased 20 to 30 times. Today an av- erage production from modern high per- formance plow faces from 47-in. to 70-in. coal seams amounts to 11,000 tpd. Present automated plow systems are equipped with the most advanced technical solu- tions, allowing the remote control of the complete system from the surface and au- tomatic operation of the plow system. There are two main reasons for this significant increase of the plow longwall performance: 1. An implementation of high automa- tion levels based upon microproces- sor technology; and 2. A significant increase of the installed power in plow faces. The diagram in Figure 1 shows that the average installed power on plow sys- tems in Germany increased significantly until the end of the last century. In prac- tical terms, the nominal power on asyn- chronous motors used on plows doubled within a couple of years. What follows is a description of a number of important high-performance GH1600 plow applica- tions from recent years. Furthermore, this paper describes anticipated developments of the plow technology in the near future. The First GH 1600 Plow at Prosper Haniel An underground hard coal mine locat- ed in Bottrop in western Germany, Pros- per-Haniel produces about 3.3 million tons of high-quality coal annually. The coal is extracted from four production levels at depths between 2,300 ft and 4,260 ft. The underground roadway sys- tem amounts to 87 miles. The mineable reserves of Prosper Haniel account for around 220 million tons. For the new panel 258 at Prosper Han- iel with an average seam height of 59 in., a plow system was selected. They opted for a plow rather than a shearer to avoid cutting adjoining rock (dilution). Such a rock cut would negatively affect the productivity of the shearer. According to the experiences of the German mining industry, at a seam height below 70 in., an automated plow Figure 1—Average installed power on plows in Germany between 1950 and 2010.