|Raising Ore in Lawrence County|
The operation of an iron furnace had to have several ingredients. The most important ingredient was iron ore which was abundant in the Hanging Rock Iron Region. There were three main layers available. The Kidney ore which was close to the surface, another layer of ore that could be found on the cliff sides or on a washout cliff and a layer that was deeper in the ground over a layer of limestone.
The Kidney ore was mined by stripping the soil off the ore and then breaking the ore into small pieces with sledge hammers and pick axes. When the ore was smaller it could be lifted and placed on a cart. The miners claimed they lifted ore and didn't mine it.
This was the first strip mining done in the area.
Bench mining was done on the cliff sides. The vein of ore was located and then the overburden was removed and the ore was removed similar to the way kidney ore was removed. When the overburden was removed back, to where it was about twelve feet deep, the miners just followed the vein around the edge of the cliff creating the appearance of big benches along the side of the hill. This is evident on the hill above the Ellisonville Rest Stop and picnic area.
The general rule for how much burden to remove and still be cost effective was one foot for every inch of thickness of the ore vein. If the vein of ore was twelve inches thick, twelve feet of overburden could be removed and still be cost effective.
Drift mining was only done when the thickness of the ore vein was four feet or more.
The ore in the HRIR was only about 30-40% iron. Modern day furnaces use ore that is 70-85% iron. In order to improve the quality of the ore in the HRIR the ore was "burned". To do this, logs were laid on the ground and charcoal and brands were laid on top of the logs. On top of the charcoal and brands was a layer of ore. This was repeated until the pile reached as high a 15 feet. Sometimes the pile was shorter. At this height the pile was set afire and burned. When the burn was complete, the ashes were raked for the burned ore.
This process of burning the ore removed 16% of the volatile matter and other types of ore were changed to hematite ore which produced iron easily. This burning of the ore is technically called calcining the ore.
In later years the Giers Kilns were used for calcination of the ore.
Copyright 2006 by Amos Hawkins