Melin Maes Glas (Greenfield Mill) established in 1776, known locally as the battery works. It was the business of Thomas Williams of Anglesey, dubbed as the 'copper king' who sent copper ore from his mines on the island to Ravenhead in St helens to be smelted, and in ingot form to Greenfield to be worked into goods under the heavy tilting battery hammers. The wheel pits are still visible where the waterwheels turned to move the hammers and left marks on the brickwork. He patented a process to produce copper bolts for ships hulls, and built a rolling mill for the production of copper rollers for printing onto cloth and to produce thin sheets of copper. At its peak this became a huge operation, extending into a brass foundry and battery mill, until by the early 1800's supplies of cheap ore from Anglesey were becoming depleted and the ships and barges using the River Dee to traverse the north coast of Wales found it increasingly hard to supply Greenfield Wharf due to changes in the shipping channel. It eventually closed in 1847 and found several industrial uses as small scale metalworks for the next century before becoming a coal yard and eventually falling into the hands of the local council in the 1970's who have since preserved it as a site of valuable local heritage.