190 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



tor, giving 2300 volts, which, is direct coupled to a Harrisburg 

 engine. A Tyrrell regulator is used to regulate the voltage 

 during the varying loads of the three phase alternator. The 

 new plant of 350 k.w. consists of a Siemen's alternator driven 

 by a Bellis and Morcom engine. This will give sufficient 

 power to work all the haulage, both underground and on the 

 surface. 



The cable, of which there are about 14,000 feet, and was 

 supplied by Siemens Bros., of London, is three phase, paper 

 insulated, jute compounded, lead covered, water resisting, and 

 steel armoured to render it pick proof, and covered externally 

 with rust resisting preservative. This cable is laid in a trench 

 cut nine inches deep at one side of the road, partly in the re- 

 turn air way, which is preferred if not too crooked, and partly 

 in the intake. As a further protection from falls of roof, when 

 the water main and cable are in the same roadway, the former 

 is placed above the latter. When laid in a heading where men 

 travel, a white line is painted on the roof above it, and calico 

 notices are fixed every fifty or sixty yards, drawing the miners' 

 attention to it. The current is conveyed into the mine at 

 2300 volts, but this is stepped down by static transformers 

 to 220 volts before use. To connect the main secondary direct 

 current cable with the 'trailing cable of the coal cutter, Mayor 

 and Coulson's joint end boxes are used. There are gas-tight 

 boxes containing fuses and switch. 



The three main cables pass down the air shaft and are 

 connected to others below in boxes. If anything goes wrong 

 with a cable in the shaft it can be detached at the box and 

 hauled to the surface for repairs. A Siemens' lightning 

 arrester is fixed at the top of this shaft. 



In the mine there is a motor generator set of 59 k.w. for 

 transforming the alternating current for the direct current 

 motor of the coal cutting plant. At present, a Goodman's 

 electric coal cutter is used for working the harder coal, but 

 the plant is capable of driving five of these chain breast ma- 

 chines. The chain -bar of this machine is 6ft. long, and the 

 cutting width of the head 3ft. Gin. The machine will cut in 

 that depth and return in 3J minutes. The direct current 

 motor of the machine, together with its switch, is enclosed in 

 an ironclad case, which is absolutely gas proof, the starting 

 resistance being manipulated by an outside handle. 



One and a half miles in from the side of the hill is located 

 ti lOOh.p. motor, three phase enclosed Siemens, belted to a 

 single ended Keavell air compressor with four cylinders, 

 which runs' at 253 revolutions per minute, and is capable of 

 compressing 358 cubic feet free air per minute to 

 701b. per square inch. It is provided with a relief 



