There are quite a number of mills in Lowertown (some say over 14). The remains of wheels, chutes etc can be seen at a number of locations.
Trelubbas Mill
The old water wheel can still be seen to the left of the archway where the adit emerges and is channelled under the lane.
Account in the Royal Cornwall Gazette of a Fire at the Flour Mills in Lowertown – 7 June 1878

