Iron Furnace Trail: Introduction

Few substances have played a larger role or had more of an impact on the peoples of this planet than iron. From approximately 4000 B.C. until the commercialization of the Bessemer process of steel manufacture (1867), iron has been a constant and consistent element in the development of races, cultures, and nations. From primitive spearheads and knives to plows, kettles, weapons, cannon, munitions, battleships, railroads, bridges, and buildings, generations have relied on the iron found within the earth’s crust to survive, to farm, to wage war, to build, and to flourish.

The colonists arriving in North America constructed an iron furnace in Virginia as early as 1609, and by 1771, the colonies were producing iron at seventy-two blast furnaces. Pennsylvania soon emerged as the largest producer of iron supporting thirty-two blast furnaces and forty-two forges. Valley Forge, Pennsylvania, where George Washington and his troops camped in 1777-78, was named for an iron forge on the Valley Creek.

As the young nation grew and settlers pushed south and west across the mountains, the need for tools, nails, guns, wheels, kitchenware, and various equipment expanded the domestic market for iron products. Blast furnaces began to appear in the new states of Ohio, Illinois, Kentucky, and Tennessee.

The iron ore deposits of the Volunteer State occur in two main areas: the red ores in East Tennessee and the brown ores in the Western Highland Rim of Middle Tennessee.

A large portion of the upland areas of the Tennessee River Valley, from Stewart to Decatur counties, has long been the source of a brown iron ore from which special grades of pig iron, such as charcoal iron, high silicon, and high-iron ferro-phosphorus have been smelted and cast, and then shipped to northern and western destinations. Considerable ore deposits remain distributed throughout several counties but are too widely scattered to provide producers the economy of scale enjoyed by the Great Lakes region, among others. Only relatively modest local operations survived into the twentieth century, and the last, at Rockdale in Maury County, has been gone since the end of World War II.

Numerous blast furnaces and forges existed in Middle Tennessee, primarily during the nineteenth century. Early adventurer James Robertson and his partners established the first iron furnace in the region in 1797 and others quickly followed suit. The early iron making operations took place on large, remote, self-sustaining plantations and often employed hundreds of workers: male and female, young and old, black and white, who mined the ore, burned charcoal, hauled raw materials, produced the metal itself, grew and prepared food, or performed the many and varied tasks of the village and its surrounding farms.

Supervising the entire operation was the multitalented ironmaster who functioned as chief executive officer, head engineer, personnel director, and sales manager. Further, it was his ultimate responsibility to make sure that there were adequate supplies of ore, wood, charcoal, and foodstuffs, as well as horses, mules, and workers who could perform the many and varied tasks. Under the watchful eye of the founder, whose job it was to keep the furnace in blast twenty-four hours a day, seven days a week, the blast furnace chemically reduced large amounts of ore and limestone flux into molten metal and waste material.

This process was accomplished by subjecting the charcoal fuel to a continuous blast of air that produced temperatures high enough to separate the iron from the other elements. These impurities joined with the fluxing material and were drawn off as slag. Guttermen made the liquid iron flow into previously prepared channels in the sand floor of the casting house. When cool, these large hardened bars (known as pigs) could be transported to forges or rolling mills for further refinement. The highly trained (and well paid) molders fashioned cast iron consumer products in a shed at the base of the furnace.

Finery forges served as adjuncts to the blast furnaces, heating the brittle pig iron in the presence of an oxidizing air blast to remove more of the carbon, and turning it into malleable wrought iron by mechanical pounding. Bloomery forges acted as small open blast furnaces that transformed relatively small amounts of rich ore directly into wrought iron by heating, cooling, and hammering. Beginning in the 1840s, most Middle Tennessee bloomeries were being abandoned in favor of puddling furnaces at the rolling mills. Some forges continued to use trip or steam hammers for turning bloomed or rolled iron into various shapes for mechanical purposes, i.e. crankshafts and axles.

In 1847, there were 21 blast furnaces, 11 forges, and 3 rolling mills operating on or near the Cumberland River in the greater Nashville vicinity. Similarly, along the Tennessee River from Hardin County to Stewart County, 12 furnaces and 8 forges were in production. The price of pig iron fluctuated very little at that time and usually averaged around $26 per ton. By 1856 pig iron output in the Western Highland Rim region had peaked at just over 50,000 tons. Tennessee usually led the South in pig iron production during the first half of the nineteenth century.

Generally, however, the industry was in a decline by the mid 1850s. Financial difficulties that led to the economic Panic of 1857 and the monumental technological changes that led to the new Age of Steel effectively doomed the charcoal iron industry of the Volunteer State. By 1860 only 16 ironworks in the region remained operational, and less than a dozen reopened after the Civil War. As the Industrial Revolution of the late nineteenth century progressed, only a few companies, primarily in Dickson and Stewart counties, survived.

The furnace stacks, the water courses, a few buildings, cemeteries, piles of slag, archaeological remains, some documents, and oral traditions are the remnants of this nearly forgotten chapter of Tennessee’s history. The remains of the hearths where immense quantities of wood were burned to make the charcoal that fueled the furnaces are still evident at some sites or are being rediscovered by archaeologists. The densely forested landscape surrounding the furnaces underwent a major change during the years of iron production because of the clear cutting of the virgin timber that was transformed into charcoal.

When visiting these quiet places, it is hard to imagine that all around once existed busy villages, characterized by an integrated work force, unceasing noise, the heat of the fires, and back-breaking, dirty, and round-the-clock work that was necessary for the production of iron. In time, the stacks have become lasting monuments to generations of iron furnace workers. Rediscovering and telling the stories of these places and the people who lived and worked at them is the purpose of the Tennessee Iron Furnace Trail.

To request a copy of Tennessee Iron Furnace Trail: A Guide to Resources on the Western Highland Rim or the accompanying video, contact the Center for Historic Preservation or the Buffalo Duck River and Five Rivers Resource Conservation and Development Councils.

Center for Historic Preservation
Box 80, MTSU
Murfreesboro, TN 31732
615/898-2947
histpres@mtsu.edu

Buffalo Duck River and Five Rivers Resource Conservation and Development Councils
BDR 931/729-2686, Ext. 102
Five Rivers RC & D – 931/368-0252