A shallow, embanked curvilinear hollow following a terraced line was seen to emerge from forestry above the Afon Cyneiniog. It has the appearance of a disused water course 0.5m-1m wide and 0.3m deep with a stony base below the turf covering. The bank, on its downhill side, is some 1.75m wide and 0.5m high. It can be followed to the north-east for 40m when it becomes a grassy terrace 1m-1.5m wide as far as SN71948955, stopping abruptly where the steep-sided river cutting is eroded. Its total extent here is little more than 100m. However, examination of air photos and early OS mapping reveals this to be the north (river source) end of a 3.5km leat which serviced the Hafan Mine (NPRN 33878). Most of its extent now lies in forestry.

David Leighton, RCAHMW, 30 July 2012