South of the site of Marine Colliery (nprn 33571) on the steeply sloping west bank of the Ebbw river stands the stone-built arched entrance of a level or adit, part of Cwm Colliery. Internally it measures approximately 1.9m wide and 1.5m high overall, the semi-circular arch rising 0.9m. The site is depicted with a single line of railway entering, as 'Old Level (Coal)' on the first edition Ordnance Survey 25in map of 1880, as `Coal Level? (apparently in use) on the second edition of 1901; by the third edition of 1921, the rails into the level have been removed and the site is not annotated. Connected to the level some 50m to the west is a ventilation shaft (nprn 85083).
B.A.Malaws, RCAHMW, 30 October 2009.