176 



COALFIELD^ AND COLLIERIES OF AUSTRALIA. 



tion of sediment in the tubes. Such boilers are suitable 

 for raising high pressure steam, and should an explosion take 

 place it is not so likely to be disastrous as with a non-tubular 

 boiler, for the part to give way will act as a relief to the 

 rest. The several parts are comparatively small, light, i\nd 

 easily handled. The boiler is housed in brickwork, which 

 also forms the firebox or chamber. 



The conveyors used at this mine are the disc type of 

 Jeffreys make, and are the first of their sort in Australia. 

 One, 750ft. long, conveys slack from the slack bins at the 



Fig. 109 Dragon Rope. 



screens down hill to the disintegrator shed, at the rate of 

 60 tons per hour. This replaces the self-acting incline 

 formerly used. The discs are lOin. in diameter, and are 

 placed every three feet on the cable. The cable used in 

 this case lin. in diameter is the "Dragon brand," made 

 specially by A. Leschen and Sons Rope Co. It is made up 

 of six strands, each strand consisting of a triangular centre 

 with two layers of five wires. Owing to the peculiar lay of 

 the wires, as seen in Fig. 109, where different strands go in 



