The Collaborative International Dictionary of English v.0.48:

Jigging \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.
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   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 template by which the action of the cutter is
       guided or limited; -- used for forming the profile of an
       irregularly shaped piece; a profiling machine.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Jig \Jig\, v. t. [imp. & p. p. Jigged; p. pr. & vb. n.
   Jigging.]
   [1913 Webster]
   1. To sing to the tune of a jig.
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            Jig off a tune at the tongue's end.   --Shak.
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   2. To trick or cheat; to cajole; to delude. --Ford.
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   3. (Mining) To sort or separate, as ore in a jigger or sieve.
      See Jigging, n.
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   4. (Metal Working) To cut or form, as a piece of metal, in a
      jigging machine.
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