The Collaborative International Dictionary of English v.0.48:

Pan \Pan\, v. t. [imp. & p. p. Panned; p. pr. & vb. n.
   Panning.]
   1. (Mining) To separate, as gold, from dirt or sand, by
      washing in a kind of pan. [U. S.]
      [1913 Webster]

            We . . . witnessed the process of cleaning up and
            panning out, which is the last process of separating
            the pure gold from the fine dirt and black sand.
                                                  --Gen. W. T.
                                                  Sherman.
      [1913 Webster]

   2. To criticise (a drama or literary work) harshly.
      [PJC]