144 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



A pair of compound horizontal engines, with 8iii. and 

 12in. diameter cylinders, and 2ft. stroke, drives, by means of 

 a belt, a Crompton dynamo of 230 volts, 112 arnp., with 550 

 rev. per minute. This is used for electric lighting, also for 

 driving the picking belt. 



While sinking, the shaft was divided into an upcast and 

 downcast compartment by a brattice of tongued and grooved 

 deal boards 6in. by lin., cut in sections at the surface ready 

 for use, to be fitted between the buntons, and were kept in 

 position by arris cleats top and bottom. (Fig. 79.) These 

 angular cleats were used so as to prevent stones from lodging 



Fig. 78. Shoes of Headfrarne. 



on the buntons. The junction of the wood and the brick 

 lining of the shaft was made tight by means of strips of brat- 

 tice cloth. The larger compartment was the downcast, and 

 the smaller, which was 12ft. square, was the upcast, and was 

 connected with the air drift at the surface. At first the ven- 

 tilation current was produced by means of a steam jet playing 

 into the drift near the top of the shaft ; a temporary chimney 

 30ft. by 3ft. square connected with the drift, increasing the 

 height of the upcast column. To facilitate driving from the 

 Birthday shaft, while the Jubilee shaft was being sunk, a 



