Ancient Monuments

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Ynys Fach Iron Furnaces

A Scheduled Monument in Cyfarthfa, Merthyr Tydfil (Merthyr Tudful)

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Latitude: 51.745 / 51°44'42"N

Longitude: -3.3841 / 3°23'2"W

OS Eastings: 304538

OS Northings: 206056

OS Grid: SO045060

Mapcode National: GBR HN.19HQ

Mapcode Global: VH6CY.9DBL

Entry Name: Ynys Fach Iron Furnaces

Scheduled Date: 9 May 1972

Source: Cadw

Source ID: 2280

Cadw Legacy ID: GM331

Schedule Class: Industrial

Category: Industrial monument

Period: Post Medieval/Modern

County: Merthyr Tydfil (Merthyr Tudful)

Community: Cyfarthfa

Built-Up Area: Merthyr Tydfil

Traditional County: Glamorgan


The monument consists of the remains of blast furnaces dating to the 19th century. Ynysfach Ironworks commenced in 1801 by Richard Crawshay as a subsidiary of Cyfarthfa Ironworks. Two furnaces were built initially, designed by the important Cyfarthfa engineer, Watkin George. Two additional furnaces were added in 1836. The remains furnaces are intact to the tops of their casting arches, built of coursed sandstone with brick arches and cast iron keystones. An iron plaque on the third from the north is marked 'WC 1836' from William Crawshay's expansion, suggesting the northern two were earlier. A tunnel behind the furnace bank carried blast pipes to the blowing arches, and is intact to the arch beneath the charging ramp.

The monument is of national importance for its potential to enhance our knowledge of 19th century industrial practices. It retains significant archaeological potential, with a strong probability of the presence of associated archaeological features and deposits. The structure itself may be expected to contain archaeological information concerning chronology and building techniques. An industrial monument may be part of a larger cluster of monuments and their importance can further enhanced by their group value.

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

Source: Cadw

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