Workshop for wagon repairs and smithy work.
Ironstone was extracted and processed at Hook Norton from the mid-1870s until after World War II. It was part of the swathe of oolitic ironstone deposits that runs from north-east England to Devon in the south west. Three companies originally mined the ore in open-cast adits but by the early 20th century only that operated by the Brymbo steel works remained commercially viable. The raw ironstone contained about 44% iron ore in beds about 5 feet thick located near the surface. The adits were simply cut into the terrain at a slight angle, allowing the ironstone to be shovelled directly into hopper wagons. The ironstone had a relatively high water content and it was in order to remove this along with some of the impurities that it was cooked (calcined) on site before being transported to the Brymbo steel works in north Wales.
The plant comprised two or more kilns served by a gantry with elevators. Hoppers were pushed individually onto the elevators, taken to the top of the gantry and then moved to tipplers where they were rotated to dump the ironstone into the top of the kilns. The calcining process was gas fired. Coal (town) gas burners were located at three levels in the lower part of the kiln. Once the ironstone had been calcined the reduced ore was released through chutes into standard-gauge wagons. The coal gas was manufactured on site in a basic retort housed in a brick building. Prior to firing, gas was temporarily stored in a large tank and was fed to the kilns through large-diameter pipes. In addition, there were two large horizontal gas storage tanks. The plant also included one or two workshops for repairing wagons etc., and a locoshed for the narrow-gauge locomotives.