The High Furnace Museum
Iron ore in the ground, and abundent wood from the forests made the area along the Blaise River and Marne River an ideal place for iron foundries. The furnaces and foundry buildings were huge.
The Chateau de Cirey had two foundries similar to this one that provided income for the estate.
A well-built high furnace could run continuously for 20 to 30 weeks. Then it would have to be emptied for repairs to the hearth, lining and bellows.
|The furnace was replenished from the opening at the top when the mass inside had settled enough to make room for another "charge". A charge consisted of 230 pounds of charcoal, 500 pounds of iron ore, plus 50 pounds of limestone and 20 pounds of clay that helped to combine the residual impurities.|
Casting a Pig
Many of the small communities along the Blaise River had an iron foundry which provided work for the people in the area. The largest amount of the iron smelted in the high furnaces was cast into "pigs"-- large bars of crude iron -- which were sold unfinished to foundries and forges for fabrication into products made of malleable iron.
To cast a pig, molten iron was tapped from the opening in the furnace into a mold prepared in a bed of sand as you see in the picture above. The furnace master and his assistant are getting the mold ready to receive the molten iron. Two other workmen are moving a pig that has just hardened and cooled. Each pig had a a number molded into it so they could keep track of production.
There were two huge bellows that provided a constant blast of air to the furnace. The bellows were stopped when the furnace was being tapped and the hearth gate was open. Otherwise the workmen would be suffocated by clouds of flame and fumes. Those who worked near the furnace wore protective clothing: leggings, heavy workshirts, aprons, and broad brimmed hats to shield them from the heat.
A furnace like this one could produce two to three tons of iron a day. Next page
The High Furnace Museum is managed by the Association pour la Sauregarde du Patrimone Métallurgique Haut-Marrais (Association for the Preservation of Metal Industry Heritage of the Haut-Marrais).
The museum is located in Dommartin-le-Franc, in the Haute-Marne district, just north of the Chateau de Cirey.