COAL CLIFF COLLIERY. 



159 



The Coal Cliff colliery is worked from two tunnels, one 

 serves as an intake, the other as a return air-way. The work 

 ings are divided into two districts ; the Western and the North- 

 ern. Cross-headings branch off from these tunnels seven and 

 a half chains apart, and hords are worked from each side of a 

 heading so as to meet those coming towards them from the 

 cross-headings on either side. When about to draw pillars, 

 roads are turned oft' to right and left from the bords to the 

 pillars 011 ^either side, a twelve foot lift is then taken off at a 

 time across a pillar. When about half the length of the pillar 

 has been extracted, the props are drawn and the roof allowed 



Fig. 91. Outcrop of Coal at Coal Cliff, where Coal was first 

 Discovered in N.S.W. 



to fall in. This relieves the pressure on the coal , thereby 

 keeping it in better condition. 



Formerly this mine was ventilated by means of a furnace, 

 but this has been superseded by a seven foot Schiele fan, 

 travelling three hundred revolutions per minute, and producing 

 15,000 cubic feet of air per minute. The Schiele fan is one of 

 the smaller type of enclosed fans which is placed eccentrically 

 within its casing, tEe casing being made a gradually increas- 

 ing volute. The air enters equally from both sides. The 

 blades are made wider near the centre than towards their tips 

 where, on account of the greater circumference, the same 



