Lower Engine House (At Sw698472)

The Lower Engine House at Tywarnhaile Mine is a disused pumping beam engine house, dating from the early 19th century. It features walls made of killas rubble and timber lintels over the openings. The building has a rectangular plan and is noted for its possibly unique design, being the last engine house fitted with a wooden bob, which is the beam of the beam engine. There is no surviving machinery.

The structure stands three storeys high with unaltered elevations. The front gable wall has a central doorway and a tall wide opening that leads to the partly fallen gable. The rear gabled end is blind. On the right-hand wall, there is a doorway on the left and a central opening on the first floor. The left-hand gable end wall features a doorway on the right and a central first floor opening. The upper floor walls are stepped in from the floors below. Inside, there are remains of the original plaster.