Coke Ovens

Laurel-Snow Coke Oven                         

Looking at an abandoned coke oven, neglected for decades and often covered in undergrowth, it’s surprising to think that it once represented a bustling and burgeoning industry – the coal and iron industry.

In the latter part of the 19th century, after the second industrial revolution had catapulted the steel-making industry into prominence throughout the world, the secluded forests of the Cumberland Plateau were transformed into bustling scenes of development and progress. Recognizing the abundance of coal, the “black gold” currency, in East Tennessee, many companies emerged, eager to slake the world’s newest industrial hunger.

The availability of coal in the Tennessee Mountains and the demand for steel were so great, in fact, that industrialists and entrepreneurs from around the country ventured to the Plateau to make their fortunes in black gold. One such man was John Thomas Wilder, a Civil War Union general from Indiana and influential industrialist. Wilder was instrumental in tapping into the natural resources of East Tennessee and helped establish Chattanooga as a competitive contender in the iron industry through the Roane Iron Works Company.

As the steel industry continued to grow in the early 20th century, fields of coke ovens and smelting factories began supplanting forests throughout the region. In addition to Wilder’s Roane Iron Works, companies such as the Dayton Coal and Iron Company, the Douglas Coal and Coke Company, and the LaFollette Coal and Iron Company materialized, capitalizing on Tennessee’s natural wealth and bringing industry and growth at a rapid rate to a part of the country that had until recently been considered “backwards.” In an effort to match the breakneck speed at which the outside world was advancing, coal and iron companies worked in earnest to harvest the fields of coal as quickly as possible. One native to the coal-rich hills of Campbell County recalls that, as a child, the sky between the neighboring hills would glow red at night, signifying the never-ending efforts of the nearby coke ovens which were kept burning 24 hours a day.

Restored Coke Oven in Dunlap, TN

Restored Coke Ovens in Dunlap, TN

Vulnerable to the ebb and flow of the economy as all demand-driven businesses are, most of the coal and iron companies throughout the Plateau succumbed to the Great Depression, shuttering their doors and abandoning coke ovens as relics of the past.

Generally, the coke ovens found in the Cumberland region were used to convert the bituminous coal mined in the local mountains into industrial coke, a relatively clean-burning fuel used in the smelting of iron ore. In a process known as “coking,” coal was shoveled into beehive-shaped coke ovens insulated with a layer of dirt and then ignited. After laborers sealed the doors with brick and mud, the coal was left burning under low-oxygen conditions for two or three days and could reach temperatures of nearly 2000C (or 3600F). In this process, the volatile parts of the coal were combusted and escaped as gases through a hole in the roof – what remained was the desired coke, which was almost pure carbon, and the by-product slag.

When coal was burned in a coke oven, the impurities of the coal not already driven off as gases accumulated to form slag, which was effectively a conglomeration of the removed impurities. Since it was not the desired coke product, slag was initially nothing more than an unwanted by-product and was discarded. Later, however, it was found to have many beneficial uses and has since been used as an ingredient in brick-making, mixed cement, granule-covered shingles, and even as a fertilizer.

Granular Slag

Slag can typically be found near any coke oven site and appears in a number of forms. In most instances, slag appears as coarse or gritty rocks that are black or gray in color. Alternatively, a variation of slag can appear as a glassy or vitreous substance coating the bricks within a coke oven.

A number of largely undisturbed beehive coke ovens can be found near the trailhead of Laurel-Snow, a beautiful trail along Richland Creek just outside of historic Dayton, TN, notorious for the Scopes Monkey Trial of 1925, which pitted Clarence Darrow against William Jennings Bryan. While most are blanketed in a quilt of kudzu and invisible to the undirected eye, some relatively intact and undisturbed coke ovens can be found in the nearby woods. These, for the most part, have withstood the wear and tear of time and trespassers.

Roof Opening of a Coke Oven; Glassy Slag is visible near opening.

Although the forest, which has been patiently trying to reclaim the land, mutes the scope of the once-bustling production, it is evident that the Dayton Coal & Iron Company once maintained an impressive business. The two batteries of coke ovens, consisting of at least 200 ovens, extend from the kudzu-covered field deep into the covered safety of the woods. Each battery is outfitted along its length with ovens on both sides; some have collapsed while others remain relatively undamaged. A man-made trench, running between the batteries and formed with cut stones, was used to collect the produced coke.

As can be seen in the picture above, the Laurel-Snow coke ovens, which are topped with a layer of soil and young trees, have a large opening at the front. Looking inside one of these coke ovens you can see the hole in the top through which gases escaped, as well as, in some cases, a somewhat glassy type of slag coating the walls. A short distance away are the collapsed entrance and old air shaft of the mine from which the coal used in the coke ovens was mined, the latter of which is accessible directly off of the Laurel-Snow trail.

Entry by Sarah Terpstra