Description

The monument consists of the remains of the southern approach of the Pwll Du tramroad tunnel, dating to the 19th century. The Pwll Du tunnel carried Hill’s tramroad from Blaenavon Ironworks through the mountain to Pwll Du. It was also connected to the Pwll Du limestone quarries, Garnddyrys Forge and the Brecknock and Abergavenny Canal. The tunnel probably originated as a mining level which, by 1800, already extended 1000m into the mountain. It was connected through to Pwll Du by about 1815 when it started being used as a tramroad and replaced the former mountain route from the quarries to the Ironworks. At 2400m it was the longest tunnel on any British horse-drawn tramroad. It continued in use until the 1860s as the most important transport link between the Ironworks and the industrial works on the N side of the mountain. There are footings for a house and possibly stables next to the entrance, and the remains of Tunnel Houses, Blaenavon Iron Company housing that was in existence in 1819. A tramroad extends S from the tunnel entrance. The tunnel portal and the line of the tramroad have recently been exposed and restored. The tunnel is not accessible.

The monument is of national importance for its potential to enhance our knowledge of the development of industrial transportation in the 18th and 19th century. The tunnel, tunnel entrances, track bed, drainage systems, embankments and revetments may all be expected to contain archaeological information in regard to construction techniques and functional detail.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw