Also try:

http://www.sia-web.org/

"Society for Industrial Archeology a primarily US based organization"
(Wikipedia)

I've seen the slags you refer to however there hasn't been enough
research to my knowledge on the four reported furnace/foundries
(primarily bog iron) in or near the Fort Drum, NY (home of the US Army
10th Mountain Division, once at Camp Hale, CO installation I was part
of the initial survey for back in 1983 to be of much use.

George Myers