ELECTRICITY IN MINING 51 



ranged at tho opposite ends of the machine. The motor, 

 which takes current through a cable reel from an adjacent 

 trolley or other circuit, also propels the loader, moving it 

 to any desired point by means of chain sprockets and suit- 

 able clutches. In operation the front end of the talkie of 

 the machine is lowered until it rests upon the ground, and 

 it is then thrust for\\^ard against the pile of material. As 

 the arm sweeps around each arm or scoop gathers up a cer- 

 tain quantity of material and carries it into channels on the 

 table until it reaches the upper end of the machine, when it 

 is emptied into the desired receptacle. The arms travel at 

 the rate of about 60 to 80 feet per minute, and the capacity 

 of the machine is reported as 90 cubic feet of loose material 

 per minute. This machine is said to have been tested suc- 

 cessfully in the handling of limestone, coal, and salt, and to 

 have shown a considerable saving of time and money over 

 hand labor wdth a shovel. 



An interesting and novel application of electric traction 

 methods is to be found in the modern telpherage system. 

 Up to the present time haulage of ores and other raw material 

 in connection with mining work has often been conducted 

 aerially, by means of a traveling wire rope or cable; and this 

 use of the wire rope represents, in the aggregate, an enor- 

 mous amount of work. As generally understood, a short 

 stretch of such work, often with a span of several hundred 

 feet between the supports, or between the support and the 

 anchorage, constitutes a cable way; in this manner a river 

 or a w^ide valley is bridged. A tramway cable, on the other 

 hand, has frequent supports, and may be several miles in 

 length. Electric telpherage belongs generically in the latter 

 class, as it is not suited to very steep grades. 



The fundamental difference between electric telpherage 

 and the traveling rope system is that in the former case all 

 the ropes or cables are stationary, the haulage l^eing effected 

 by means of an electric motor or telpher traveling along one 

 of the cables, and taking its current, by means of a short trolley 

 pole, from a trolley wu'C above. In the simpler form the 

 telpher travels along a flexible wire cable; for heavier work 

 a rigid metal rail supported between posts is employed, and. 



