Genealogist Tom Pierce has published a well researched article online that primarily deals with  iron furnaces owned by Benjamin Blackford ca 1820 in Shenandoah Co. VA.   Much of the information is generic to the times, e.g. the  list of the usual occupations found at an iron-making operation of that time-- most of them calling for skilled, experienced workers.  Of interest also, is the list of workers at Isabella Furnace (located near Luray, VA) found  in the 1820 census, pg 158A -- 20+ white men.  (The 1820 census of Shenandoah County clearly identified the residents at each furnace and forge).   For more detail, see:

http://www.rootsweb.com/~vashenan/blackfordiron.html

Gus Carr