Ironworking

An ironworks is an industrial site for the extraction of iron ores and for the smelting and/or forging of iron. The main components include mines for obtaining the iron ore, ore roasting hearths, smelting furnaces, forging hearths, and buildings. Sites are usually recognised in the field by the presence of smelting and forging waste, in particular slag, and burnt areas indicating hearths and furnaces; these may come to light during field survey, or by chance from ploughing, excavation or development. Some sites have earthworks in the form of shallow depressions and slag heaps. Documentary evidence and place-names may also be of use in locating and identifying sites. Medieval ironworks differ in scale from post-medieval ironworks and are more difficult to identify.

Iron ore occurs in many parts of England although it is quite restricted in outcrop within these widespread areas; ironworks are, therefore, widely distributed throughout the country shows a concentration of sites in the Weald; this area, with the occurrence of ores and ready supply of charcoal and clay, was a centre for iron production in the later medieval period, and due to the intensive research of the Wealden Iron Research Group, many sites are known archaeologically.

Ironworking is known from the Iron Age period, for instance at Cholesbury Camp and form part of a continuous tradition of manufacture and use of iron. Roman ironworking has been identified at Touchbridge Farm. Archaeologically known medieval ironworks date from the 6th century onwards; early Saxon sites with iron-working debris dating to the 6th or 7th centuries have been discovered. A medieval blacksmith's workshop was discovered at Stock Lane, Whaddon. Iron-working gains intensity in the post-medieval period, although there are still small iron-working smithies, such as at Boycott.

In general, ironworks developed from having simple bowl furnaces for smelting to having more sophisticated furnaces with facilities for tapping the slag and continuous charging. During the 14th century there is evidence of the increase of the capacity of bloomeries with the use of water power for driving hammers and bellows. When iron is smelted a lot of the unwanted material, such as stone and other minerals, can be tapped out. However, the iron (called the bloom after this first stage of smelting) also has to go through a stage of red hot hammering because it still contains impurities.

Ironworks have been found in both urban and rural locations, usually located on naturally or artificially levelled, well-drained ground close to a river or other water source; in many cases they are sited over or with easy access to raw materials such as iron ore, charcoal and clay.