Site Event/Activity record ECH5582 - An Archaeological Watching Brief at Bank Park, Warrington, Cheshire

Report on watching brief carried out on the site of a structure that stood at the northern tip of the former lake in Bank Park, prior to the re-developmentof the site. The Watching Brief was confined to the site of a rectangular building sited immediately adjacent ot the northern edge of a fishpond, both features are shown on historic mapping of the area, first appearing on the 1st edition 6 inch to 1 mile Ordnance Survey map of 1849. Excavation consisted of a single area measuring 15 by 12m at the eastern end of the development. An upper deposit of 20th century made ground was found to cover the whole area. The excavation exposed a group of walls constrcuted in blocks of copper slag which were the foundations of a "pump house" shown on 1890's mapping. However large sections of foundations had been destroyed by a modern ( about 1980) drainage system and the buildings precise form was difficult to identify from the surviving remains. The northern most extent of the parks original fishpond was also located. No evidence for the buildings function survived, though map evidence suggests that it primarily served as a shelter. The Copper slag block can almost certainly be traced to the copper works at Bank Quay, Warrington, owned by Thomas Patten. Although no direct dating evidence was found for the construction of the building, the use of copper slag foundations suggest that it predates the closure of the Bank Quay copper works prior to 1795. The foundations of Bank Hall are built using identicial material. The use of copper slag as a building material originated in the mid 18th century when the industrialisation of copper production resulted in the production of large quantities of copper slag. This could be cast into blocks for use as a construction material thus making use of what was otherwise a waste product though its extensive use in domestic dwellings was rare. The blocks were impermeable to air and moisture which resulted in cold and damp dwellings. Instead it was generally used for foundations, retaining walls and occasionally decorative features.