The crusher house at Llywernog mine is a rectangular two-storey rubblestone building with a pyramidal slate roof. To the rear (north) is a ramp leading to a door with gable over, leading to the second floor to which ore was brought for crushing. A pair of late-nineteenth century cast iron crushing rolls from LLawrcwmbach Mine have been placed on beams inside the building. On the east side is a raised waterwheel case, built of rubblestone, with an access door on its east side. A slate sill probably marks the top of the structure when it supported a 40ft (12.2 metres) diameter wheel, installed in 1861. This was replaced by a 50ft (15.2 metres) diameter wheel, made in Llanidloes, in 1874/5, and the side of the case were raised by c1.5 metres to accommodate it.

The mine worked sporadically betwen 1882 and 1891, and was reopened in 1907, but without success. The wheel remained as a landmark, but became unsafe and was demolished in 1953. The site reopened as the Llywernog Silver-Lead Mining Museum in 1973.

Information from Cadw Listed Buildings database.

W J Cromtpon, RCAHMW, 16 January 2014.