\Jig"ging\, n. (Mining)
The act or using a jig; the act of separating ore with a
jigger, or wire-bottomed sieve, which is moved up and down in
water.
{Jigging machine}.
(a) (Mining) A machine for separating ore by the process of
    jigging.
(b) (Metal Working) A machine with a rotary milling cutter
    and a templet by which the action of the cutter is guided
    or limited; -- used for forming the profile of an
    irregularly shaped piece; a profiling machine.