MINING 



309 



for the waggons, -which is sometimes, however, arched in brick to allow of a water- 

 course beneath it. 



Fig. 1460 shows two vertical projections of a portion of a walled shaft with but- 

 tresses, as built at the mine Vater Abraham, near Marienberg. J is a section in the 

 direction of the vein g h, to show the roof of the shaft, i, a section exhibiting the 

 slope of the vein g h, into which the shaft is sunk ; m, is the wall of the vein ; k is the 

 roof of the same vein ; n, buttresses resting upon the flanks of the shaft ; g, great arcs 

 on which the buttresses bear ; y, vertical masonwork ; z, a wall which divides the 

 shaft into two compartments, of which the larger p is that for extracting the ore, and 

 the smaller for the draining and for the descent of the miners. 



Fig. 1461. c D is the shaft in which the vertical crank-rods c, g, e, d, move up and 

 down. F, is a double hydraulic wheel, which can be stopped at pleasure by a brake 

 mounted upon the machine of extraction. G, is the drum of the gig or whim for 

 raising the corves or tubs (tonnes) ; H, is the level of the ground, with the carpentry 

 which supports the whim and its roof. K, is the keystone of the ogee arch which 

 covers the water-wheel ; a, is the opening or window, traversed by the extremity of 

 the driving shaft, upon each side of the water-wheel, through which a workman may 

 enter to adjust or repair it; b, line of conduits for the streams of water which fall 

 upon the hydraulic wheel ; c, g, double crank with rods, whose motion is taken off 

 the left side of the wheel ; e, d, the same upon the right side. The distance from H 

 to F is about 22 yards. 



Figs. 1462, 1463, present two vertical sections of the shaft of a mine walled, like the 

 roof of a cavern, communicating with the galleries of the roof and the wall of the 

 vein, and well arranged for both the extraction of the ore, and the descent of the 

 miners. The vertical partition of the shaft for separating the passage for the corves 

 or tubs from the ladders is omitted in the figure, for the sake of clearness. 



In fig. 1462, A B are the side-walls supported upon the buttresses c and D ; in fig. 

 1463, E is the masonry of the wall, borne upon the arch F at the entrance to a gallery, 

 the continuation being at G, which is sustained by a similar arch built lower. 



1462 



1463 



t, is the vault arch of the roof, supported upon another vault M, which presents a 

 double curvature, at the entrance of a gallery ; at H is the continuation of the arch or 

 vault L, which underneath is supported in like manner at the entrance of a lower 

 gallery. 



a, b, c, d,Jlff. 1462, are small upright guide-bars or rods for one of the corves, or 

 kibbles. 



e,f, g, h, are similar guide-bars for the' other corf. 



i i, are cross-bars of wood, which support the stays of the ladders of descent. 



k k, are also cross-bars by which the guide-rods are secured. 



t, a corf, or extraction-kibble, furnished with friction rollers ; the other corf is sup- 

 posed to be drawn up to a higher level, in the other vertical passage. 



jp%s._1464, 1465 represent in a vertical section the mode of timbering the galleries 

 of the silver and lead mines at Andreasberg in the Hartz. Fig. 1464 shows the plan 

 viewed from above. Upon the roof of the timbering, the workman throws the waste 

 rubbish, and in the empty space below, which is shaded black, he transports in his 

 waggons or wheel-barrows the ores towards the mouth of the mine. Fig, 1465 is the 



