Dunlap Coke Ovens Earthcache EarthCache

In 1899, a coal mine was opened on Fredonia Mountain overlooking Dunlap, TN. For almost 28 years, the mining operations grew into an industrial complex. It was the start of the Sequatchie County coal and coke industry which transformed the small agricultural region into a thriving industrial center.

The Douglas Coal and Coke Company of Delaware began the Dunlap operation with $400,000 of capital stock put up by investors from New York and Delaware; the company purchased 14,000 acres of coal lands in the initial venture and officially announced its intentions on September 30, 1900. Almost immediately a rail spur was laid from Nashville, Chattanooga and the St. Louis Railway to the base of what is now called Fredonia Mountain. A gravity incline railway was constructed to allow the coal mined on the Cumberland Plateau to be lowered to the mail rail tipple located on the valley floor.

The incline was over 3900 feet in length and operated on a gravity principle which allowed the weight of the descending incline car or monitor to pull the empty car back up the steep mountain grade. The cars speed was kept in check by an operator at the top who controlled the main pulley or drum with a friction brake attached to the drum. The incline rope, made of a single length of 1-1/14 inch cable, made severe turns around this cast iron pulley. The system worked very well and inclines of this design operated in the Sequatchie Valley for many years, attesting to the skill of the engineers who designed the system.

The Dunlap incline cost approximately $13000 to build and today visitors still marvel at the vast effort that was expended to blast out the route through the sandstone cliffs above the city. Historic photos taken during construction have illustrated that the construction was done totally by the manual labor provided by local residents who worked with picks, shovels and black powder explosive. At the top of the incline a massive sandstone rock overhangs the old rail bed. It is evident that the attempts were made to blast the huge rock away with the black powder explosives available during the turn of the century. It was all in vain. The hanging rock still shadows hikers who follow the steep grade of the incline more than ninety years after the drill holes were hammered by local workers.

Constructed at the base of the mountain were a series of beehive ovens designed to turn coal into coke for use in the iron and steel foundries of nearby Chattanooga. The company store was built in 1902. The store allowed the company to pay wages in script redeemable only at the company store.

The first coke ovens were built in 1902, directly behind the commissary, and the stone for the retaining walls were quarried from property near the incline. These first 24 double block beehive coke ovens were constructed to convert the unusable mineral to a high grade industrial coke. The soft nature of bituminous coal mined from the Sewanee coal seam of the Cumberland Plateau on Fredonia Mountain, though a good quality of coal, was not suitable for domestic purposes. But the ovens allowed coke to be made from what was otherwise worthless coal.

In 1904 Douglas Coal and Coke ceased to exist due to labor problems and from problems in separating dirt or rash from the coal. Closed temporarily the operation reopened within the year with new investors, but met with disappointment and failures as a coal washer was needed to remove the dirt from the coal.

In 1906, the facilities began to once again thrive. New owners changed the name to Chattanooga Iron and Coal Company and with new capital began designing a steam powered coal washer and 144 additional coke ovens to make the operation more profitable. With the coal washer effectively removing the unwanted dirt, the operation continued to grow until 1916 when a boiler explosion destroyed the washer and damaged the incline tipple.

In 1916 a new railroad up Little Brush Creek created the demand for more coke production. Along with a one million dollar coal washer, 100 more beehive coke ovens were built on the east end of the site. These last ovens and the coal washer were used very little due to the company filing for bankruptcy in the mid 1920's. A total of 268 stone ovens had been built when, in 1927, the mining operations were shut down due to failing coal prices and the onset of Depression.

The coke ovens lay dormant for more than 50 years, exposed to the ravages of nature, garbage dumpers, and rock thieves who dismantled stone from the ovens. In the mid 1980's local citizens formed a historical group and began efforts to clear away the debris. Soon, a park was created to preserve this piece of the county’s heritage.

The sandstone and brick walls of the ovens still stand much as they looked when masons built them. Excavation work continues to uncover more of the ovens. The park has been placed on the National Register of Historic Places.

The Coke Ovens Museum, adjacent to the ovens, is on Mountain Creek Road, within the city limits of Dunlap. It is a two-story replica of the commissary, or company store, and stands on the original site. The major portion of funds for the construction came from a bequest of David Gray, deceased. The museum is open on week-ends, and other times by request.

The museum currently houses the largest collection of regional historic coal mining photographs in the state of Tennessee. Hundreds of donated mining artifacts are on display inside the museum.

The Dunlap Coke Ovens Park was added to the National Register of Historic Places in 1985.

A hard, gray, massive, porous fuel, coke is the solid residue remaining after bituminous coal is heated to a high temperature out of contact with air until substantially all components that easily vaporize have been driven off. The residue is chiefly carbon, with minor amounts of hydrogen, nitrogen, sulfur, and oxygen. Also present in coke is the mineral matter in the original coal, chemically altered and decomposed. Since the vapor-producing constituents are driven off during coke productions, coke is an ideal fuel for stoves and furnaces in which the environment is unsuitable for the complete burning of bituminous coal itself. In the form of oven coke it is primarily used when a porous fuel with few impurities and high carbon content is desired, as in the blast furnace to make iron. Coke is also used in other metallurgical processes, such as the manufacture of ferro-alloys, lead, and zinc, and in kilns to make lime and magnesium. Exceptionally large strong coke is known as foundry coke and is used in foundry cupolas to smelt iron ores. The smallest sizes of coke are used to heat buildings.

The majority of coke produced in the United States come from byproduct coke ovens. The coke is prepared in retorts or furnaces of silica brick, and the byproducts (chiefly ammonia, coal tar, and gaseous compounds) are saved. These volatile gases are collected and sent to the byproduct plant where various byproducts are recovered. In nonrecovery coke plants, originally referred to as beehive ovens, the coal is carbonized in large oven chambers; the partially combusted gases collect in a common tunnel and exit via a stack. In recovery coke plants the waste gas exits into a waste heat recovery boiler which converts the excess heat into steam for power generation.

Petroleum coke is the solid residue left by the cracking process of oil refining. Natural coke, or carbonite, is formed by metamorphism from bituminous coal when intrusive igneous rock cuts across a vein of coal.