276 University Geological Survey of Kansas. 
a means of completely draining the same. A post, O, is 
driven into the ground at a point eighteen inches to two feet 
of the end of the arm, D, and is provided with a cleat or is 
notched, so that the arm, D, may be pushed down and held 
in that position by the notch or cleat. By this arrangement 
the jig cell may be raised out of the water. A round stick, 
P, is driven into a hole bored through the end of the arm, D, 
and furnishes a double hand hold for one facing the end of 
the arm. 
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Fig. 54. Hand jig. Side view. 
The method of operating is as follows: The ore is thrown 
into the jig cell, F, while it stands suspended above water, 
The operator then lowers the cell by freeing the arm, D, from 
the catch on the post, O; then taking a handle in each hand, 
and raising. the arm, D, he submerges the cell with its con- 
tents, and by means of a series of upward pushes and down- 
ward pulls the water in the tank is forced up through the 
grating and then back again, by the alternate rising and fall- 
ing of the cell. The operator usually stands upon a spring 
board, and by slightly bending his knees, then suddenly 
straightening out, a spring is given to the board which is 
imparted through the operator to the lever, thence to the 
screen. By these movements the separation is accomplished, 
as will be explained in greater detail later on. 
Power Jigs.—The power jig is for concentrating ores on a 
large scale, and is relied upon in this district as the principal 
means of separating the ore from the waste products. The 
jig is found only in those districts where the extraction and 
concentration of ores is a fairly stable and permanent business. 
