528 MINING INDUSTEY. 



The hoisting machinery consists of an engine, of which the cylinder is 

 15| inches in diameter by 36 inches stroke, to which steam is supplied by one 

 tubular boiler 14 feet long by 52 inches in diameter. Power is transmitted 

 from the main engine shaft by a pulley and belt (not shown in the drawing) 

 to the stamp mill, while the winding apparatus is operated by a combination 

 of toothed gearing and friction. A section of the winding-spool, showing the 

 method of applying the friction, is shown in Fig. 2 on the same plate. The 

 spool or drum consists of two interior end pieces, a, a, of cast iron, circular in 

 form, having a hub at the center and a flange, c, c, at the circumference, to 

 which the staves, h, h, are bolted, as shown in the drawing. A cast-iron rim, 

 d, d, is put on the outside of the spool, to give additional security to the staves 

 and to provide projecting flanges between which the rope may be wound on 

 the spool. Thus constructed, the spool is supported on the spool shaft E, and 

 is free to turn in either direction. It is placed between two friction-flanges 

 F, F, likewise circular in form and provided at the periphery with a > -shaped 

 groove. The ends of the spool-staves have a corresponding form so that they 

 may fit into the grooves of the flanges. These latter are attached to the spool- 

 shaft, E, by a feather, on which they may be moved toward or from the spool. 

 In the former case the flanges, pressing against the ends of the spool, impart 

 to it the motion of the shaft, winding the rope and raising a load from the 

 mine ; while in the latter case, the pressure being relieved, the spool is free, 

 and may be reversed for lowering the skip, or may be held firmly by means 

 of the brake-band, g. The flanges are pressed against the spool by means of 

 two rods, h, h. The ends of the spool-shaft are bored out so that the rods may 

 be placed in the position shown in the drawing, and pressed, when desired, 

 against pieces of iron, ^, i, which are long enough to bear evenly against the 

 ends of the flange-hubs, F, F. These pieces of iron are about 1^ inch thick 

 and pass through slots cut in the shaft, which is 7 inches in diameter ; they are 

 kept in place by pins aty. By a system of levers, not shown in the drawing, M 



the attendant may, by a single movement, press the rods h, h, against the 

 flanges, thus setting the spool in motion, or, with equal facility, relieve the 

 pressure, reversing the motion of the spool, or holding it firmly by means of 

 the brake, g. 



It will be seen in Fig. 1 that the spool-shatt is furnished with a spur- 



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