Coalbrookdale is a side valley of the Ironbridge Gorge in the borough of Telford and Wrekin and ceremonial county of Shropshire, England, containing a settlement of great significance in the history of ferrous metallurgy. It is in the ancient manor and ecclesiastical parish of Madeley. It was one of the birthplaces of the Industrial Revolution. It is home to the Ironbridge Institute, a partnership between the University of Birmingham and the Ironbridge Gorge Museum Trust offering postgraduate and professional development courses in heritage.
In 1651, the manor was leased to Francis Wolfe, the clerk of the ironworks, and he and his son operated them as tenant of (or possibly manager for) Brooke's heirs. The surviving old blast furnace contains a cast iron lintel bearing a date, which is currently painted as 1638, but an archive photograph has been found showing it as 1658. What ironworks existed at Coalbrookdale and from precisely what dates thus remains obscure. By 1688, the ironworks were operated by Lawrence Wellington, but a few years after the furnace was occupied by Shadrach Fox. He renewed the lease in 1696, letting the Great Forge and Plate Forge to Wellington. Some evidence may suggest that Shadrach Fox smelted iron with mineral coal, though this remains controversial. Fox was evidently an ironfounder, as he supplied round shot and grenado shells to the Board of Ordnance during the Nine Years War, but not later than April 1703, the furnace blew up. It remained derelict until the arrival of Abraham Darby I in 1709. However the forges remained in use. A brass works was built sometime before 1712 (possibly as early as 1706), but closed in 1714.
Darby renewed his lease of the works in 1714, forming a new partnership with John Chamberlain and Thomas Baylies. They built a second furnace in about 1715, which was intended to be followed up with a furnace at Dolgûn near Dolgellau and taking over Vale Royal Furnace in 1718. However, Darby died prematurely in 1717, followed quickly by his widow Mary. The partnership was dissolved before Mary's death, Baylies taking over Vale Royal. After Mary's death, Baylies had difficulty extracting his capital. The works then passed to a company led by his fellow Quaker Thomas Goldney of Bristol and managed by Richard Ford (also a Quaker). Abraham Darby II was brought into the business as an assistant manager when old enough.
The company's main business was producing cast iron goods. Molten iron for this foundry work was not only produced from the blast furnaces, but also by remelting pig iron in air furnaces, a variety of reverberatory furnace. The Company also became early suppliers of steam engine cylinders in this period.
The Company operated a forge at Coalbrookdale from 1720, but this was not profitable. In about 1754, renewed experiments took place with the application of coke pig iron to the production of bar iron in charcoal finery forges. This proved to be a success, and led to the partners building new furnaces at Horsehay and Ketley. This was the beginning of a great expansion in coke ironmaking.
In 1768, the Company began to produce the first cast iron rails for railways. In 1778, Abraham Darby III undertook the building of the world's first cast iron bridge, the iconic Iron Bridge, opened in 1780. The fame of this bridge leads many people today to associate the Industrial Revolution with the neighbouring village of Ironbridge, but in fact most of the work was done at Coalbrookdale, as there was no settlement at Ironbridge in the eighteenth century.
In the 19th century, Coalbrookdale was noted for its decorative ironwork. It is here (for example) that the gates of London's Hyde Park were built. The blast furnaces were closed down, perhaps as early as the 1820s, but the foundries remained in use. The Coalbrookdale Company became part of an alliance of ironfounding companies called Light Castings Limited. This was absorbed by Allied Ironfounders Limited in 1929. This was in turn taken over by Glynwed which has since become Aga Foodservice.
Several of Coalbrookdale's industrial heritage sites are waypoints on the South Telford Heritage Trail, including: Coalbrookdale Railway Station, the Quaker Burial Ground, the Darby Houses, Tea Kettle Row and the Great Western Railway Viaduct.
In the century after the Old Blast Furnace closed, it became buried. There was a proposal for the site to be cleared and the furnace dismantled, but fortunately, it was decided to excavate and preserve it. It and a small museum were opened to celebrate 250 years of the Company in 1959. This became part of a larger project, the Ironbridge Gorge Museums. Its Museum of Iron and the Ironbridge Institute form the sides of an open space, on another side of which is the Old Blast Furnace, now under a building to protect it from the weather. The fourth side is a viaduct carrying the railway that delivers coal to the Ironbridge Power Station. One of the two tracks is due to be taken over by Telford Steam Railway as part of their southern extension from Horsehay. The Museum's archaeology unit continues to investigate the earlier history of Coalbrookdale, and has recently excavated the remains of the 17th century cementation furnaces, near the site of the Upper (formerly Middle) Forge.
The lintels of the furnace bear dated inscriptions. The uppermost reads 'Abraham Darby 1778', probably recording its enlargement for casting the Iron Bridge. It is unclear whether the date on one of the lower ones should be 1638 (as it is now painted) or 1658 (as shown on an old photo). The interior profile of the furnace is typical of its period, bulging around the middle, below which the boshes taper in again so that the charge descends into a narrower and notter hearth, where the iron was molten. When Abraham Darby III enlarged the furnace, he only made the boshes wider on the front and left sides, but not on the right where doing so would have entailed moving the water wheel. The mouth of the furnace is thus off-centre.
Iron was now being made in large quantities for many customers. In the 1720s and 1730s, its main products were cast iron cooking pots, kettles and other domestic articles. It also cast the cylinders for steam engines, and pig iron for use by other foundries. In the late 18th century, it sometimes produced structural ironwork, including for Buildwas Bridge. This was built in 1795, 2 miles up the river from the original Ironbridge. Due to advances in technology, it used only half as much cast iron despite being 30 feet (9 m) wider than the Ironbridge. The year after that, in 1796, Thomas Telford began a new project, the Longdon aqueduct. It carried the Shrewsbury Canal over the River Tern and was supported by cast iron columns. Charles Bage designed and built the world's first multi-storey cast-iron-framed mill. It used only brick and iron, with no wood, to improve its fire-resistance. In the 19th century ornamental ironwork became a speciality.