Cross section reveling the infrastructure of an operating underground iron ore mine. Note that the blue material that looks like it could be water, is in fact the ore body.
Iron Mining; Underground Mining; Oliver Iron Mining Company
Document describing a collection of records held at the Iron Range Research Center documenting the activity of Peter Del Greco, a former United States Steel employee.
Del Greco, Peter; Chisholm (Minn.); United States Steel Corporation; Iron mines and mining--Minnesota.
