THE CONQUEST OF NATURE 



is first drilled into the ore near the top of the embank- 

 ment, and into this hole a stick of dynamite is dropped 

 and exploded. This enlarges the cavity sufficiently 

 so that a quantity of blasting powder may be poured 

 in and set off, tumbling the ore down within reach of the 

 shovel. 



This ore is frequently almost as hard as iron itself, 

 many of the pieces thus dislodged being too large for 

 convenient handling, either by the steam shovel or 

 in the chutes at the wharves, and must be still further 

 broken up. This is sometimes done by the men with 

 picks; but in mining on a large scale, where the deposit 

 is all of a very hard nature, crushing machines are 

 used. 



In this manner the steam shovel is kept constantly 

 supplied with ore for the waiting train of cars. These 

 trains are arranged on a track running parallel with the 

 track from which the steam shovel operates, and at such 

 a distance that the centre of the car will be directly 

 under the opening in the bottom of the shovel when 

 it is swung around on its crane. The engineer in 

 charge of the locomotive drawing the train stops it 

 in a position so that the first shovelful of ore will be 

 dumped into the forward end of the first car. As each 

 successive shovelful is deposited, representing about 

 one-fifth of a car-load, the train is pulled or backed 

 along the track about one-fifth of a car-length. In 

 this manner it is only necessary for the steam shovel 

 to be swung into the same position and dumped at 

 the same point each time to insure the proper loading 

 of the cars. 



[276] 



