SOl'TH BULLI AND BKLLAMBI COLLIER IKS. 197 



ihe different districts, but now a separate rope is used for each 

 district, driven by its own motor. The advantages of this 

 change are obvious ; the waste of power in circulating a rope 

 where it is not required is saved, so a smaller driving engine 

 will do; the longer a rope the heavier and stronger it nmst be, 

 the elasticity increases with the length of the rope, and the 

 jerks are worse with a heavy than a light rope, thus making 

 the skips travel unsteadily ; there are more bends in one 

 continuous rope than when a series of ropes are used, and if 

 .a breakage occurs when the single rope method is employed, 

 the whole system is stopped, whereas if a district rope 

 breaks, there is only a local stoppage. With separate ropes, 

 when the main rope shows signs of wear, it may be put to 

 work in a district where the demands on it are not so great; 

 in this way the life of a rope may be extended. As electric 

 motors are used for the different districts, when one is not in 

 use, the electricity which would otherwise be consumed can 

 be used for other purposes, or the load on the engine at the 

 .surface may be lightened. 



Forty chains in from daylight is a 20 h.p. haulage motor 

 of the slip-ring rotor type, with a tramway style of controller 

 and outside resistance, for a branch line 960 yards long. One 

 mile thirty chains from daylight is a 75 h.p. motor, having 

 720 revolutions per minute, also of the slip-ring rotor type, 

 with external resistance and tramway type of starter. This 

 circulates a rope four and a half miles total length, which 

 is being extended all the time, and is capable of working 

 another two miles of rope or one mile of line. Both these 

 plants get their first reduction by belting; any further re- 

 duction is obtained by spur gearing. All the haulage gear 

 was built up at the company's shops. 



Where tommy-dodds are used at curves, and the line 

 has an incline, those on the up-track are connected by a cap, 

 which allow the pulleys a certain amount of play, at the same 

 time stiff eiiing them. 



The clips that connect the skips with the rope are the 

 ordinary screw pattern employed on the South Coast. They 

 i\re made of crucible seel. 



The coal skips, as they come out of the mine, are now run 

 into tipplers similar to those employed at the Metropolitan 

 'Colliery, Helensburgh. The on-coming full skip pushes the 

 empty one off, which then runs down an inclined track at the 

 bottom of which it bumps against an obstruction, and the 

 recoil shunts it on to a branch which leads to the mouth of a 

 tunnel, where it is clipped on to an endless rope. 



A three-skip tippler (Fig. 122) is now in course of erec- 

 tion, which will be power-driven to ensure regular speed of 

 rotation. The tippler will be started and stopped auto- 



