POSITION OF A SHAFT. 



139 



In certain cases, when the lode lies at a considerable 

 inclination from the perpendicular, the shaft should be sunk 

 along the lode rather than in a vertical direction. 



Adit levels, which facilitate the proper working of a 

 mine, also help to drain it; and, in consequence, they 



FIG. 68. 



A. 6, Lode, a, Shaft. 



B. , c. Lode, o d, Perpendicular shafts, 

 the lode, e, e, Crosscuts. 



c, Where shaft intersects 



should be driven at as low a level in the valley as possible, 

 and with a very gentle slope, just sufficient to enable the 

 water to flow away. 



With regard to the size of shafts and adits, the dimen- 

 sions of the former vary from 6 by 5 feet to 8 by 6 feet, 

 while the engine shafts are usually 11, 12, or 13 feet by 



