The Collaborative International Dictionary of English v.0.48:

Timberman \Tim"ber*man\, n.; pl. Timbermen. (Mining)
   A man employed in placing supports of timber in a mine.
   --Weale.
   [1913 Webster]

WordNet (r) 3.0 (2006):

timberman
    n 1: an owner or manager of a company that is engaged in
         lumbering