9781439834220.ch10

The outer most arms can be hydraulically adjusted to

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Unformatted text preview: different seam thickness and to prove the most effective pattern of cut. The outer most arms can be hydraulically adjusted to vary diameter of cut. An adjustable outer chain gives a desired shape of gallery. Coal from the face drops to the bottom and is pushed on a scraper chain conveyor by rotating arms, which are provided with ploughs. The scraper chain conveyor runs centrally through the machine and carries the coal to the rear end. The rear end can be swung on either side by 40° or can be raised or lowered hydraulically. The entire cutting unit is supported on hydraulic cylinders, which can tilt the cutting unit by 4 degree in the horizontal or vertical plane. This allows borer to negotiate the irregularities of the seam. This machine can drive the gallery of 1.8 to 2.3 m high and 3.2 to 3.8 m wide while advancing at the rate of 0.3 to 0.75 m/minute. Likewise there are few other designs that are available and used for mining the coal seams. 10.4 CLASSIFICATION BASED ON WEIGHT The roadheaders based on machine weight, cutter head power could be classified5 as light to heavy duty units, which are capable of covering face size up to 45 m2; and they...
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