HETTON COLLIERY. 295- 



these beams at right angles to them, near the guide posts, to 

 help keep them in place. Two long beams (d) were bolted 

 on to the first beams at right angles, and on these were 

 stacked a heap of railway iron pig-sty fashion. The deeper 

 the tubbing sunk the greater the friction, and consequently 

 the greater the weight required, until eventually it reached 

 1000 tons. At about 50ft. from the surface in the downcast 

 shaft, the tubbing passed into clay, and the man in charge, 

 thinking it would be safe to add any further rings to the bot- 

 tom, inside the shaft, instead of to the top and forcing down 

 the whole lining, gave instruction for the water to be baled 

 out. Unfortunately, the tubbing was not down far enough 

 into the clay, so when the support of the water and sand from, 

 the inside was taken, away, the tubbing burst, and quicksand' 

 rose in the shaft. As the original tubbing could not be 

 driven down any further, it had to be telescoped. The smaller 

 diameter tubbing was forced down in a similar manner to- 

 the other; only a square wooden frame was built on the top, 

 at the corners of which were posts 30ft. long. This enabled 

 the tubbing to be weighted at the surface ; but fresh rings 

 were added inside the shaft above water level. It was only 

 found necessary to have 20ft. of the smaller diameter tubbing,, 

 and then the shoe was taken off and a bell-shaped ring added 

 from below, so as to bring the shaft from there onwards to its 

 original diameter, thereby minimising the friction of air due 

 to a constricted passage. The rest of the tubbing was put 

 together from inside the shaft. It used to take six men a 

 shift of 10 hours to dig out three feet of clay, and put in a 

 ring of tubbing. When putting in the tubbing, not only 

 were the vertical joints of adjoining rings made to break 

 joints, but the different rings were begun and ended at various 

 places, so as not to have a continuous line of weakness in any 

 one part of the tubbing. The joint between the inner and 

 outer tubbing was made water-tight with cement. When 

 sinking the tubbing from above, the sand and water was re- 

 moved by a bucket 2ft. in diameter and 4ft. long, with a 

 clack at the bottom 5in. square. This was worked up and 

 down till full, and then drawn to the surface. This sand- 

 pump was found to work better when a few inches of piping- 

 of ample area was fixed below the clack. Later on, when 

 the rings were added to the lining from below, and loose sand 

 was met with, it was found advisable to use segments one- 

 eighth the size of those generally employed, as they were 

 easier to handle. When replacing the shoe, two segments 

 were taken out at first before a new one was inserted, after 

 which a segment of the shoe was taken out for every new seg- 

 ment put in, so as to leave room to work in easily. The 

 last new segment had to have one end pushed in at the back 



