15(3 



COALFIELDS AND COLLIERIES OF AUSTRALIA. 



are suspended ready in the shaft : the guide ropes are situated 

 .at diagonal corners of the cage, two to each cage. The steam 

 power for this 'pit is provided by three Lancashire boilers. The 

 electric light is generated by two Siemens direct-current 

 dynamos, driven by two vertical engines of Tangyes' make. 

 The larger of the two dynamos is lOkw., 45.5 amp., and 220 

 volts. The electric light is used at the surface, and also about 

 the pit's bottom. At the main shaft is a steel pit-head frame 

 of English make. The full skips, after being weighed near 

 the pit's mouth, are conveyed by means of a creeper-chain up 

 an incline to the tipplers. After being emptied, the skips are 

 conveyed along a level place by means of another creeper- 

 ^hain, and are then sent down a pair of rails curved first in one 



Fig. 90. Tippler. 



direction horizontally and then in another, so as to gradually 

 break their impetus till they reach the mouth of the pit again. 

 A piece of angle iron is fastened to either side of the skips so 

 as to hold them in the tipplers. Mr. Robertson maintains that 

 it is not the speed at which a tippler revolves that breaks the 

 coal, but the drop the coal is given, for if a box of coal be 

 quickly and completely turned upside down on to the ground 

 the coal is not disturbed and shaken to the same extent as if it 

 were spilt from the height at which it started. Carrying out 

 this idea, Mr. Robertson devised a tippler that revolves on an 

 axle in such a way as to leave the skip open on the top. In 

 order to keep the coal in the skip till it reaches the screen, a 



