Wikipedia
Gwennap is a village and civil parish in Cornwall, England, United Kingdom. It is about five miles (8 km) southeast of Redruth.
In the 18th and early 19th centuries Gwennap parish was the richest copper mining district in Cornwall, and was called the "richest square mile in the Old World". It is the location of the Great County Adit, and once-famous mines such as Consolidated Mines, Poldice mine and Wheal Busy. Today it forms part of area A6i (the Gwennap Mining District) of the Cornwall and West Devon Mining Landscape World Heritage Site. It lends its name to Gwennap Pit where John Wesley preached 18 times between 1762 and 1789, although Gwennap Pit is about to the north west at the hamlet of Busveal near St. Day. The pit was caused by mining subsidence in the mid-18th century. After Wesley's death the local people turned the pit into a regular circular shape with turf seats.