The Collaborative International Dictionary of English v.0.48:

Mucker \Muck"er\ (m[u^]k"[~e]r), n.
   A term of reproach for a low or vulgar labor person. [Slang]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

mucker \muck"er\ (m[u^]k"[~e]r), n. (Construction)
   An excavating machine designed to remove particulate material
   from within a confined area, as in a tunnel or mine.
   [RDH]

The Collaborative International Dictionary of English v.0.48:

Mucker \Muck"er\, v. t.
   To scrape together, as money, by mean labor or shifts. [Obs.]
   --Udall.
   [1913 Webster]