Chartered Institute for Archaeologists 2022

26 A highlight of the site and recording project was the blast furnace, which was prioritised early in the recording schedule because of its heritage significance and the level of detail required. Built in 1979, the uppermost plant was almost the same height as the top of St Pauls Cathedral, rising to approximately 104m. The blast furnace was the focal point in the flow of materials around the Redcar site and its primary purpose was to produce molten iron to a specific tonnage and quality as required at the steel plant. Although at first glance often taken as comprising the upstanding furnace, the blast furnace facility actually contains a wider sprawl of associated infrastructure including gas and dust collection, cleaning and processing, conveyors and charger, slag and waste material processing, as well as the gas, air and water required to drive the process. At the height of operation, the furnace provided the continuous production of iron at a capacity of 63,000 tonnes per week. The team was fortunate to be able to gain access into the blast furnace facility and was able to record the principal elements from inside the structure and from the multitude of working platforms. The Basic Oxygen Steelmaking (BOS) Plant received the molten iron from the blast furnace. The iron was transferred into 240-tonne-capacity converter vessels where oxygen was blown in to convert the iron to high-quality steel. The steel works building was made up of a series of steel-framed bays measuring up to 700m in length and with the larger bays being up to 70m in height. Large overhead cranes were used to carry heavy ladles filled with molten metal around the various stations. The molten steel was poured into continuous casting moulds where it was formed into straight ingots for immediate use in adjacent rolling mills or for sale as raw material. The survey provided a record of the structure and layout of the building and there was specific emphasis on documenting and describing the process of manufacturing and materials through the building and its place within the wider site. Blast furnace charging conveyor ©TEP