Blast Furnaces

Cadw's description

Location

Three extant furnaces and the remains of others, stand in a row on the north-west side of the furnace yard, behind the cast houses.

History

In 1787-9, the partnership of Thomas Hill, Thomas Hopkins and Benjamin Pratt leased this site from Lord Abergavenny. Three furnaces (nos 1-3) were built in 1788-9, together with casting sheds and a blowing engine house (located between furnaces 1 and 2), at a cost of £40,000. This was the first purpose-built multi-furnace ironworks in Wales. By 1796 it was the second largest producer of iron in Wales, with an annual output of 5.4864 tonnes. Of these furnaces, only the northern most (No 1) survives today. The others were demolished in the late nineteenth century. In about 1810 two more furnaces (Nos 4 and 5) were added, together with a second engine house. These were modified in 1881 to cast ingots for use in Gilchrists newly perfected process for making Bessemer steel. Both survive in their modified form, although much of the face stone was removed in 1911 to build a church. A sixth furnace was erected in 1860 on the site of the old engine house. This furnace was a circular steel clad type. Most of the structure was removed for scrap in 1930. Its buried base survives. The group is of international significance in the history of iron making.

Exterior

The standing furnaces are built of stone and brick, on a square plan. Their ashlar stone elevations taper towards the top, although each survives to just below original height. The side elevations contain small, intact tuyere arches.

Furnace No 2 - This has a number of tie bars in the upper part of its front and side elevations. The furnace retains its original stone casing and cast house (listed separately).

Furnace No 4 - This has a large hearth opening or tymp; formed as an outer semi-circular brick-lined arch and an inner segmental brick lined arch. Above the level of the top of arch, all facing stone of the outer furnace shell has been removed, exposing stone core and the conical refractory brick lining.

Furnace No 5 - The same form as Furnace No 4. Hearth opening arch survives less well.

Reason for designation

Part of Scheduled Ancient Monument Mm 200.

Included at grade I as internationally important early coke-fired blast furnaces.

Group value with other listed items as Blaenavon Ironworks.