138 COALFIELDS AND COLLIERIES OE AUSTRALIA. 



the top of each joint by three fin. bolts in each end. Butt 

 joints are better than scarfed joints, as they are easier to take 

 out later on, when the next section of walling reaches it from 

 below. The curbs are either set on beds dressed for them cut 

 in the side of the shaft, or if the rock is not strong enough , 

 18-20 two-inch iron dowels are let 2ft. or 3ft. into the side, 

 depending on the strength of the rock, and the curb rests on 

 them. Care must be taken to have the curbs set level and true 

 to the centre of the shaft. The brick work is built up solid for 

 not less than 6ft. high, after w r hich the walling is carried up 

 as thick as possible without cutting any bricks. The bricks 

 should be hard, not affected by changes of temperature, and 

 must not absorb much water. The brickwork was started with 

 headers, the colonial bond being used, i.e., a row of headers 

 and then three rows of stretchers. The British bond of alter- 

 nate rows of headers and stretchers both keys and weathers 

 better. The brickwork is laid in cement mortar, made of 3i 



. 72. Brickiii"- Cradle. 



