at Wallsend Colliery, June, 1835. 



351 



the dumb furnace drifts. The drifts of communication between the dumb 

 furnace drifts, and the workings were called gas-pipe drifts, because they 

 were subject to be charged, and generally were charged with an explosive 

 current. Those gas-pipe drifts were only travelled by the wastemen for 

 the purpose of repairing and keeping them in good order, and no light 

 except the Davy lamp was ever used in them. For the more effectual ven- 

 tilation of the Bensham workings, four pits, the A, B, C, and G, Pits, had 

 been sunk to it. See the plan, Plate XVI. 



The A and B were the up-casts, powerful furnaces being placed at their 

 bottom, and the C and G. were the down-casts. Each up-cast pit had its 

 furnace supplied by a current of inexplosive air from the workings of the 

 the whole coal*, while the dumb furnace drift at the B Pit carried off the 

 contaminated current from the pillar working, the dumb furnace drift at 

 the A Pit not having been completed at the time of the accident. 



The G Pit had been sunk to the High-main Seam 13 feet diameter, and was 

 divided into two coal and one engine-shaft, by a three-tailed brattice ; thus 



Top of 



_XBH3 



^^=559?^^- 



the Pit Heap. 



30 fathoms of the 

 brattice was 

 blown out here, 

 and its broken 

 fragments scaf- 

 folded & closed 

 the mouths of 

 the two Ben- 

 sham Shafts. 



* The first working of a colliery is called working in the whole, in contradistinction to 

 the pillar working, which is called working in the broken. 



