Part of the Maenofferen Slate Mine (NPRN 400427), the weighbridge is situated at the West mouth of the Mill Floor Tunnel and opposite the Dressing Mills, the weighbridge and associated weighbridge building weighed the trucks carrying unprocessed slate up from the underground workings. Much of the building and weighbridge is demolished, with the surviving remains relating to the final weighbridge, constructed, according to the plans held by J. W. Greaves and Sons Ltd after 1939 and prior to 1976. This comprises a roughly rectangular single storey building orientated NW-SE and measuring 2.3m x 2.8m. It was constructed using a single thickness of breezeblocks and photographs of it standing show a pitched slate roof with a skylight in the SW facing roof, a door and window in the SW side opposite the weighbridge, and a window in the NW side facing the Dressing Mills. Internally the building contained the weighbridge scales that connected to the external weighbridge platform, both of these features partially survive.

A 0.7m section of brickwork, between the tunnel entrance and southern corner of the breezeblock building may relate to an earlier weighbridge structure.

References: Plans referred to are held by J. W. Greaves and Sons Ltd, Blaenau Ffestiniog

Louise Barker & Spencer Gavin Smith, RCAHMW, August 2011.