Evidence of a Gin Gang?

What is a Gin Gang?

Old OS maps of the barn show a large circle at the western end. Suggestions are that it could have been a round building, perhaps a horse gin gang, or something to do with lead mining which is common in the Peaks.  

Barn_OS_Closeup

gin gangwheelhouseroundhouse or horse engine house, is a structure built to enclose a horse mill, usually circular but sometimes square or octagonal, attached to a threshing barn. Most were built in England in the late 18th and early 19th centuries. The threshing barn held a small threshing machine which was connected to the gin gang via wooden gearsdrive shafts and drive belt, and was powered by a horse which walked round and round inside the gin gang.