Penny Rigg Quarry Adit
This is actually the leat system used to carry water from Tilberthwaite Gill down to the waterwheel at Penny Rigg Copper Mill.
Part of the old leat is accessible (dangerous) from within the Penny Rigg Quarry and is a constructed section as it passes below the quarry floor. Other sections must have been mined or tunneled through the rock surrounding the quarry.
This section lead through beneath the quarry wall and down to a small pond that fed the waterwheel and is now flooded and blocked at the quarry end by fallen rock.