294 COALFIELDS AND COLLIERIES OF AUSTRALIA. 



well soaked in red lead ; the object of letting a portion of the- 

 iron rest on iron was so as to keep the wood in place, and not 

 to let all the weight c-ome on the bracket of the casting In 

 the case of the air shaft, there was a machine-planed face 

 three inches wide, and the joint was made with red lead, which 

 made a good fit. The ordinary segments were three feet 

 hi"-h and were connected together with bolts from the inside 

 of "the shaft, and as all the flanges and strengthening brackets 

 were also cast on the inside, this left the outside smooth, so- 



Fig. 190. Frame used when sinking shaft lining. 



that it could pass down through the strata without any ob- 

 struction. At the bottom of the tubbing was a shoe or cut- 

 ting edge. This was a ring similar to those above, only it 

 was but one foot deep, and instead of a flange at the bottom 

 it was bevelled off. The successive rings were put together 

 on the surface, and forced down by weights piled on the top. 

 First, four pairs of vertical posts were put in position, as 

 shown at (a), Fig. 190. These acted as guides to two hori- 

 zontal beams (b), which were notched where they rested on 

 the tubbing. Small pieces of timber (c) were bolted on to 



