MANUFACTURING IRON ALONG THE NEW RIVER IN VIRGINIA
Howard M. Mandigo
Indiana Area Junior High School
Indiana, Pennsylvania 15701
Iron was probably first produced by the Hittites about 1500 B.C. This metal cannot be separated from its ores by heating alone; extraction requires the presence of carbon. Perhaps the chance combination of charcoal with iron ore, probably in a camp fire, led to the discovery of the process of purifying iron. Some prehistoric "scientist" observed the phenomenon and interpreted the facts correctly and the iron age began. The knowledge of iron was then carried from one civilization to another by the men with iron weapons who were conquering other peoples.  Some conjecture on the work of primitive iron makers and Early Egyptians using foot bellows have been illustrated by interested artists. 
Probably the first attempts to manufacture iron in America were made in Eastern Virginia at Falling Creek in 1622. An attack by Indians, which included the destruction of the furnace, eliminated the possible success of such an enterprise in Virginia for almost 100 years. The Saugus Ironworks founded in 1641 in Hammersmith, Massachusetts, is recognized as "the first successful furnace" in America.  Governor Alexander Spotwood is generally credited with the earliest successful manufacture of iron in Virginia by arranging for the immigration of Palatinate iron workers. However, others appear to have been interested in this industry. Large sums were being used to build "furnaces and other works" as early as 1727 and by 1732 there were three blast furnaces and one air furnace established in Virginia. Apparently there were no forges. These facts were recorded by Colonel William Byrd in his book A Progress to the Mines in 1732.  The Valley of Virginia had many forges and furnaces before the Revolutionary War and many others were built before the year 1800. The present Southwest Virginia Counties of Smyth, Washington, Carroll, and Wythe, all had some interest in the iron business about the same time. 
The New River-Cripple Creek region has a rich history in the production of iron in the late seventeen and early eighteen hundreds. This mineral region contains at least 300 square miles near the New River in what is now Pulaski and Wythe counties between Macks Creek, southwest of Pulaski on the east and the village of Speedwell on the west. The Wytheville-Pulaski line of the Norfolk and Western Railroad forms the northern boundary and the Iron Mountains the southern boundary. Through this region the New River flows generally northeastward from a gap in Iron Mountain south of the town of Ivanhoe for seventeen miles to Draper Station in present Pulaski County. Cripple Creek is the principle tributary which rises west of Speedwell and flows eastward eighteen miles to join the New River between the Lead Mines (Austinville) and Ivanhoe.
In this geographic region numerous sites along the creeks and river were ideal for washing ores and locating industeries. In fact, all the requirements for making iron were found in and around what is now the southern part of Wythe County, Virginia. Great forests were growing there and were much needed for the charcoal making. From innumerable outcrops limestone could be cut to supply iron furnace building materials and / or the continuous need for limestone flux ingredients. Adaquate water power was present in the form of Cripple Creek, Francis Mill Creek, and other branches of the New River drainage system. Especially important was the obvious abundance of hematite iron ore in the nearby hills. This is the story of how the settlers of the region produced iron for profit from the seventeen nineties (1790's) until about nineteen twenty (1920). It took men of vision and capital who were capable of acquiring the land with the forests, ores, limestone, and water power, and a human workforce with the skills necessary to produce iron.
The historical records show and the examined physical remains verify that primarily cold blast charcoal furnaces were used in those early days to produce iron along Cripple Creek. One must completely understand what is meant by the phrase "cold blast charcoal iron furnace" to appreciate the basics of how early New River iron was produced. The term furnace implies heat or hot and surely a source of heat energy was a must for the seperation of iron from the other mineral materials called the "gangue" with which iron always exists in combination in the iron ores. The fuel used to produce the heat energy was charcoal which was also necessary as a reducing agent in the process of purifying iron. It was an ideal furnace fuel, almost free of sulphur, and its ash consisted largely of lime and alkalies which supply part of the flux required in the process of smelting ore. Many early American Ironmasters continued to use charcoal as long as the required timber could be obtained in sufficient quantities.
This is the interesting process of how charcoal was produced. It was called "coaling" and chemically it was the destructive distillation of wood. By heating wood strongly without access to air the combustible gases methanol, acetic acid, and other volatile products were driven off leaving only the charcoal.  It took about twelve specialized workers called "colliers" to keep one furnace going. A circular area called a "pit" or "hearth" thirty to fifty feet in diameter was prepared. Trees were felled, trimmed, cut into lengths, and bundled into cords by the "woodchoppers". The cut wood was then brought from the forest to the pit site on a hauling sled. The wood was stacked by the colliers in a conical shape standing the sticks on end. This was done around a central framework of sticks composing a chimney several inches in diameter and about six feet high. The completed cone was about twenty-five feet in diameter at the base. A layer of loose earth, damp leaves, or turf was spread over the entire pile. Chips, dry leaves or other inflammables were placed in the chimney, lighted at the top and the flue partly closed with turf. Holes were drilled in the sides to draw in a limited air supply. The smoldering pile was tended continuously day and night by the collier who lived close by in a rudimentary log and sod hut. All traces of flames were carefully smothered. It took three to ten days to char an entire pile. Various woods were used in charcoal making but hickory was considered the best species.  After charring was completed the collier raked the charcoal into small piles to prevent fires by spontaneous combustion. The product, which consisted almost entirely of carbon, was usually not made until a short time before it was needed.  After cooling it was hauled to and stored in a stone-walled coalhouse located near the furnace.  The furnaces of Wythe County used on an average approximately 750 bushels of charcoal every twenty-four hours. That represents about nineteen cords of wood. One acre of twenty-five year old trees produced about twenty-five cords of wood. It seems that each furnace consumed almost one acre of forest every twenty-four hours. 
Careful examination of the standing remains of the early furnaces along Cripple Creek reveals most impressive structures and the results of masterful workmanship. They were all built close to the side of a small hill so a bridge could be built across to the stack. The ores and other raw materials called the "charge" were put into the furnace from the top. In size most were about twenty-five feet on each side of a square base but the stack heights varied from thirty-two feet to forty-seven feet.  Their basic shape is usually described as a "truncated pyramid." The earlier furnaces were entirely open at the top; later ones had a cylindrical erection of brickwork over the top to protect the workers from the heated gases and smoke rising from the furnace. Into the top of the stack or through a door in the tunnel head the raw materials were "charged." Workmen called "fillers" continuously crossed over the wooden bridge connecting the tunnel head with the bank bearing their baskets or wheel barrows loaded with materials to feed the hungry furnace.
The outside of the stack was usually built of large blocks of precisely cut limestone. The interior was lined with fire brick. Between this inwall and the outside limestone the space of several inches was filled with clay, coarse mortar, or rubble, to protect the outside limestone from the decomposing effects of the high temperatures within. Most of the stacks were reinforced, strengthened, and / or supported with strong iron girders, rods, or plates embeded in the walls. The widest part of the inner chamber of the stack the bosh measured eight to eleven feet but the nine foot diameter was the most common.  Below the bosh was the narrower crucible and below that the hearth or reservoir at the bottom of the furnace into which the molten metal flowed. The hearth was relatively small, only a few feet in diameter because of a necessity to concentrate the molten iron to prevent it from solidifying. The narrowing region below the bosh and above the crucible supported the major weight of the charge. 
The term "cold blast" comes from the fact that an "extra" supply of air at atmospheric temperature (unheated) was forced or blown into the fire chamber or crucible region of the furnace. This was done on one, two, or three sides of the furnace where there were arched recesses with a small aperture allowing the insertion of the tuyeres (twee-yairs) a nozzle-like fixture and an iron pipe connecting it to a blowing device.  Some furnaces used water driven bellows or blowing cylinders, or tubs to furnish the blast.  The energy to provide this cold blast came from Cripple Creek, or one of the other nearby creeks or runs. The creek was usually dammed at an appropriate location and the water diverted to the furnace area by means of a ditch and / or wooden troughs, perhaps made of hollowed out tree trunks. The water was used to rotate a water wheel, most frequently of the overshot design that could be driven with a relatively small amount of water flow. The water wheels were quite large probably about twenty-four feet in diameter. The size estimate comes from the comparing of old photographs and some conjecture on the meaning of old records. The blast for the earlier furnaces was presumably obtained by means of large double bellows made of wood and leather. They may have been from twenty to twenty-five feet long and several feet wide. Later came the blowing tubs, including cylinders, pistons, and connecting rods, all made mostly of wood. After many improvements the so-called double cylinders came into use. These consisted of two wooden cylinders set side by side that blew into a third container that helped to control and maintain a uniform air pressure. These overcame the unsteady and insufficient blasts of the old bellows. 
Some of the Wythe County furnaces used steam power to generate the cold blast.  This probably meant the use of a "boiler" to generate steam to drive some type of horizontal reciprocating engine with a flywheel which provided torque for gears connected to some form of blowing tubs. 
Geologically the Virginia deposits of brown hematite intervene between the Potsdam Sandstone and the base of calciferous limestone and are generally more or less disintergrated or decomposed into variegated clays.  The rich in iron "Cripple Creek ores" formed in ancient caverns and pot-holes of all sizes and shapes where iron bearing muds settled, filling them entirely. Afterwards, the iron concentrated into masses or pipes or gravels of iron ore (primarily brown hematite Fe2O3). The ores occurred in clays in clefts and cavities in limestone deposits that were irregular but their extent was considered very great. The ore was derived from decomposition of iron pyrites as demonstrated by the fact nodules and masses of the mineral partly decomposed were frequently found.  There were two distinct classes of ore distinquishable by their origins. The first, "limestone ores" were lying in the Lower Silurian Limestone. The second, the so-called "mountain ores" were geologically connected to the Potsdam Sandstone. All of the ores showed as high a general character as any brown hematite ore mined in the country (54% metalic iron).  The quality was such it probably melted easily in the furnace and required a minimum amount of both flux and fuel.  Since the mountain ores were more inaccessible most of the early Cripple Creek / New River furnace iron came from the limestone ores. It was generally found in loose granular clay very free of flint and was easily washed out yielding a full one-half clean ore.  A typical mine site was described for the "Graham bank" of Cedar Run Furnace as being located one and one fourth miles S.E. of the furnace, three quarters of a mile W.N.W. from New River, consisting of a circular pit eighty feet in diameter and fifteen to eighteen feet deep, with the bottom not gone through. No limestone had been observed at that point.  The approximate locations of some of the early mines are marked on the Geologic Survey Maps of the region. The actual field locations were found to be known by few local residence. Most mine sites are difficult to reach because of private property restrictions or are blocked and obscured by extensive overgrowth from the relentless processes of succession!
The ores were undoubtedly washed in nearby streams before they were transported to a furnace. Extraneous dirt was probably washed from the ore in at least some kind of sluice.  The precise methods and kinds of equipment that might have been used in the construction of some type of "buddle" is uncertain. One elderly gentleman living near a Wythe County furnace recalled visiting a cleaning area when he was about fourteen years old and remembered, "workmen picking balls of clay or mud from a trough and throwing them into a field." He could not recall for sure if there were any mechanical parts or belts or machinery involved. A local hunter pointed out an area where there had once been a dam and a shallow lake or pond he claimed had been used for washing iron ore. It was strategically located between an old mine site and a not too distant furnace.
The operation of an iron furnace as a chemical process was fairly simple, but its management involved continuous difficulties. The starting or the "blowing in" of the furnace was a rigorous process. The stack was first filled with charcoal and lighted at the top. After several days, when the fire had burned down and reached the tuyere opening, the furnace was refilled with charcoal. The fire then worked back to the top. The blast was then applied and ore and limestone (flux) put in from the tunnel head in gradually increasing quantities. After a few days, slag and iron ran into the hearth below. The proportions of ore and flux and charcoal were gradually increased until the furnace was working normally.  The furnace was continuously filled with alternate layers of charcoal, ore, limestone (flux) for probably nine months or whatever length of time it was making iron and was known as the "blast". The materials were normally not weighed before being "charged" but simply measured in buckets or baskets. 
The cold blast charcoal furnace itself served two major functions: It not only reduced the iron ore to iron but also removed the earthy gangue as slag. The charcoal was required for the first function and the limestone for the second. The products were pig iron, slag, and flue gas with probably seven major chemical reactions taking place. One primary process began as the charcoal burned in the blast and some of it formed carbon dioxide gas as heat energy was produced.
1) C - O2 CO2 - Heat
As carbon dioxide was formed just above the tuyeres (twee-yairs) and rose through the furnace it came in contact with more of the charcoal and was reduced to carbon monoxide gas (CO).
2) CO2 2CO
The carbon monoxide thus formed was actually the "mystery" agent that reduced, or removed the oxygen from, the iron oxide (ore) to produce metalic iron.
3) Fe2O - 3CO 2Fe - 3CO2
The white hot liquid flowed to the hearth at the bottom of the furnace as it was reduced; and periodically accumulated quantities were tapped off.
The second major process began in the middle of the furnace as the limestone was decomposed into calcium oxide. This probably occured because of the high temperature.
4) CaCO3 CaO - CO2
The calcium oxide then combined with the silica to form calcium silicate slag which liquified far more easily than the silica.
5) CaO - SiO2 CaSiO3
This glassy slag seperated from the iron and was also collected in a pool at the bottom of the furnace. Since it had a much lower density than the metal it floated on top of the melted iron. This was especially important because it helped prevent the reoxidation of the iron. The melted slag was also tapped off every few hours. The discarded slag was usually dumped into piles near the furnace by an unskilled workman called a "gutterman." Pieces of slag can still be found near the sites of the old furnaces. Not all the impurities in the iron found its way into the slag. Manganese, phosphorous, silicon, and sulfur were usually found present in small quantities in the reduced iron. 
Furthermore, air normally contains some moisture which reacts with the carbon (charcoal) to produce hydrogen and increase the carbon monoxide supply. This does absorb some heat energy in the process.
6) C - H2O CO - H2 minus heat
Experience has shown that when moisture is added and higher temperatures used to compensate for the heat absorbed by the reaction, smoother furnace operation and higher productivity result. The hydrogen, H as well as the carbon monoxide produced by this reaction provides increased reducing power.
7) Fe2O - 3H2 2Fe - 3H2O 
These latter reactions demonstrate how varying weather conditions as well as the changing physical condition and water content of the ores and / or flux being used could have a profound influence on the furnace operation.
The "Ironmaster" was the general manager of the furnace enterprise. He was usually the owner or part owner of the company. Many of the early ironmasters became outstanding civic and political leaders while not actively engaging in the iron industry. 
Ordinarily it was the responsibility of the "founders", with the aid of the "keepers" to produce quality iron despite all the varying factors. Since the furnace had to be operated night and day the workers labored in two twelve-hour shifts changing at six o'clock. Not many workers were needed to operate the furnace. Two founders, two keepers, two guttermen, two or three fillers, a potter, wheelwright, a blacksmith and a few laborers included all of them. 
The cold blast charcoal iron furnace was sometimes called a "fickle mistress" by those who were dependent upon her operation for economic well being.  For many, there was some unexplainable reason why ore, charcoal, and limestone produced a hardening metal of a thousand uses. This process was often considered . . . "The Mystery of Making Iron." 
Without modern laboratory methods and equipment there must have been a lot of guesswork and trial and error involved in operating the iron furnace. The skills of "burdening" the furnace determining the proper proportions of the ore, flux and fuel for the charge were learned with experience and a certain intuition and good judgement that was considered a "gift" that the successful founders and ironmasters possessed.  The furnaces of Wythe County consumed on an average approximately 750 bushels of charcoal, 12 tons of ore, and unknown quantities of limestone (flux) to produce about five tons of iron every twenty-four hours. 
During a blast whenever reduced iron had accumulated sufficiently in the hearth it was tapped off into molds to form pig iron, or delivered into large ladles and in turn was poured into small ladles and then into molds for castings. True pig iron was formed when molten iron was allowed to flow from the furnace into the casting bed in front of the hearth and the sand had been sculptured to allow the liquid to follow a main stream or feeder trench called a "sow," then into numerous side gutters called "pigs." These terms, still in use today, come from a comparison of the iron casting bed to a sow and her litter of suckling pigs. Before the iron became hard the pigs were separated from the sow and the latter broken into smaller pieces. 
The casting of hollow ware such as pots, pans, skillets, kettles, and stove parts was done by the "potter" using sand molds in the casting shed. A pattern of wood or iron made slightly larger than the finished casting was placed in a box called a "flask" and a sand mixture with a small amount of clay and moisture was packed tightly around the pattern.  Many flasks were made in two parts so the pattern could then be easily removed. A channel or "gate" had to be provided (carved in the sand) from the mold to the pour or "sprue" hole as well as an overflow vent called a "riser" before the mold halves were closed and secured. Molten iron was then poured into the sprue and it filled the cavities completely. When the iron cooled the sand was scraped away to remove the casting.  All unusable parts, such as the sprues, risers, and gates were cut off and the pieces sold at reduced rates as "gate metal" along with the pig iron.  Many decorated stove plates and other castings still remain bearing testimony to the artistic yearnings of these early artisans in iron. 
Considerable information presented here was obtained as a result of the extensive research done at Hopewell Village, Pennsylvania. Many of the slides which accompanied the original presentation of this paper at the 1984 New River Symposium were taken at Hopewell. They have many working examples of the equipment and facilities developed by the very early iron making industry. The materials used and many processes involved are well demonstrated, exhibited or explained. It is recommended that everyone who is interested in this topic write for complete information.  A visit to Hopewell is a most rewarding and free adventure into the past!!
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Last Updated: 08-Jul-2009