Blaenavon Ironworks began production in 1789 with 3 furnaces. Two more furnaces were built c1810. The original partnership, led by the Hill family, sold the works in 1836 to the Blaenavon Iron and Coal Co. Initial investment at the site included the construction of a water balance lift for conveyance of pig iron from the site, but further investment did not occur until the 1850s. A new blast engine was built, and a new furnace was blown in during 1861. Investment was also made on a new site kown as Forgeside. By 1900 only one furnace remained in blast, but this was blown out in 1904. Thereafter the site was used by small-scale engineering companies until it became a guardianship monument in 1974.

Calcining kilns were used to roast iron ore in order to drive off impurities before the iron ore was charged into the blast furnaces. The kilns were charged from the top and drawn from the bottom, and hence were often, as here, buuilt against a bank to facilitate ease of use. The calcining kilns were erected in the C19 but are probably not the kilns shown on a map of 1819, but are later. Although 13 kilns survived in a continuous row in 1880, only evidence of 10 can now be seen.

Two kilns at the E end are well preserved, next to which are 6 kilns in declining state of preservation and 2 more at the W end are now merely depressions in the ground. The whole row is about 55m long, and the kilns are approximately 2.5m high. The best preserved kilns are of snecked rubble strengthened by tie bolts with oval plates, and brick dressings to round draw arches. The brick kiln linings have an elongated circular plan. Two kilns adjacent are at the same level, then the level drops, with the 5th kiln retaining its draw arch.

R Hayman, Hayman & Horton, 6/1/2003