Possibly recorded in 1724 but not named, this mine likely owes its origins and its name to the Acts of Union in 1707. The mine today takes the form of many overgrown and forgotten remains in Unity Wood, just north of St Day.
Early workings were at surface near William's Shaft of Tolgullow United Mines, confined to the outcrop of "Grove Lode". Underground, it can be presumed that a branch of the Wheal Busy old adit, or the Wheal Rose adit had been driven into workings at a shallow depth of about 30fms. Later, in the 1790s the County Adit was brought under from its branch to Wheal Unity Wood/North Wheal Unity.
Today, a pleasant walk through the woods is possible and two grilled shafts are passed. These are Harvey's (or later Skip) Shaft, and the smaller Water Shaft (or Footway). The two are such on Grove and Wood Lode respectively and link underground through old workings.
Data courtesy of Ben Sum, Helston (30/9/20).
Buckley, J 2007 "Killifreth Mine" Penhellick