Disgrifiad
Figure 78. At Pen y Bryn in Nantlle, water wheels on the hillside powered rod-systems operating the pumps in Twll Balast and Old Pen y Bryn pit. The pumps raised the water to the outflows, which took the water through tunnels to where it emptied into the river on the valley floor to the south
Opsiynau lawrlwytho a prynu