CRANE. | Prospecting, Mining and Milling Machinery. 237 
ELEVATORS. 
As elevators constitute a very important part of the con- 
centrating machinery, too great attention cannot be given to 
their construction. Differing as they do only in regard to 
the fineness and quantity of material handled, the method of 
construction for the various forms is practically the same, ex- 
cept possibly in the case of tailings elevators, which of neces- 
sity must be higher and bear greater loads. 
The body of the elevator consists of a long rectangular 
shaft, larger at the base than at the top. Plate XXVI. The 
_ framework is firmly fastened to posts set in the ground, be- 
tween which, and sunk into the ground several feet, is a box 
or boot, which forms a receptacle into which the material to be 
elevated isrun. Pulleys are placed at the top and bottom of 
the elevator frame, upon which a belt bearing iron cups or 
buckets operates. The belt is always driven by the top pul- 
ley, and for this reason the interior and tailings elevators 
are built somewhat differently, although they operate in ex- 
actly the same manner. 
It is found that the elevator belts carry best when they are 
inclined ten to twelve degrees from the vertical. The buckets 
are built so as to be full when at the inclination given. Tig- 
ure 43. There are two ways of building an elevator so that 
this inclination or batter may be given to the belt which sup- 
ports the buckets, namely: First, by giving one side of the 
elevator the required inclination, keeping the other side 
vertical, and then shifting the pulleys so that the belt will 
run parallel with the side to which the batter is ‘given; sec- 
ond, by inclining the whole elevator, which in itself will 
throw the pulleys out of the perpendicular, thus giving the 
belt the required batter or inclination. The first method is 
much to be preferred, for the reason that any material fall- 
ing from the elevator in the act of being raised or while 
dumping will drop back into the receiving basin or boot at 
the bottom without striking against the side of the elevator. 
In the second method of construction, all material falling 
will strike and run down the back side of the elevator and 
thus rapidly wear through. Occasionally both methods are 
