EAST GRETA COLLIERY. 



333 



cage at a time. The upper and lower decks are linked toge- 

 ther, such a joint preventing accidents, which used to happen 

 with stiff frames where the grade of the tunnel varies. The 

 mouth of the tunnel is protected by bars pivoted and counter- 

 balanced so that they can be easily raised. There is also a 

 horizontal door working on a hinge, one for each half of the 

 tunnel. These are so connected together with chains passing 

 over pulleys that when one is open the other is closed. The 

 banksman raises the door over the up-coming cage, and when 

 it reaches the surface the empty skips run on rails, fastened to 

 the top of the closed doors, into the cage. (Fig. 209.) 



Fig. 209. Unloading Top Deck of Cage. 



A second tunnel, known as the steam jig, is Tft. by 7ft., 

 and only has one pair of rails. Two ropes pass down it, which 

 are wound up 011 two different engines. One is led down the 

 side of the tunnel and winds from No. 5 level to No. 4 level, 

 while the other winds from No. 4 level to the surface, and is 

 worked from a 5ft. drum, the engine being geared from 21 to 



The tunnels and jigs are sunk with self -tipping tanks 

 known as "alligators." The bail to which the capping of the 

 rope is attached is fastened to the tank at a point below the 



