Part of the main copper mining complex, this three-chambered building lies opposite another building. Within the eastern chamber, the largest, lies a large stone cube that might have been an engine base of some sort, and much of the walling has collapsed, reaching only 03.m to 0.4m in height. A piece of firebrick also suggests the previous existence of a now collapsed chimney. Alongside this building, to the east, can be seen both a track and another section of wall, this measuring 0.3m high. Noted during an upland survey conducted by Archaeophysica during 2005-6