The Collaborative International Dictionary of English v.0.48:

Stamping \Stamp"ing\,
   a. & n. from Stamp, v.
   [1913 Webster]

   Stamping ground, a place frequented, and much trodden, by
      animals, wild or domesticated; hence (Colloq.), the scene
      of one's labors or exploits; also, one's favorite resort;
      in this sense, often called stomping ground. [U.S.]

   Stamping machine, a machine for forming metallic articles
      or impressions by stamping.

   Stamping mill (Mining), a stamp mill.
      [1913 Webster]

WordNet (r) 3.0 (2006):

stamping mill
    n 1: a mill in which ore is crushed with stamps [syn: stamp
         mill, stamping mill]