GM611

Cwm Glo pit and ironstone tip  

12/02/2018  

Designated  

Merthyr Tydfil  

Cyfarthfa  

303870  

205710  

Industrial  

Colliery  

Post Medieval  

The monument comprises the remains of a complex of features relating to several periods of coal extraction, the main being the remains of Cwm Pit (or Robbin's Pit). Cwm Pit developed after 1826 and had its own tramroad incline linking it to the Cwm Pit Railway and so directly to the Cyfarthfa Works. The pit had closed by 1905. The earliest remains comprise a small pond and an associated leat designed to take water to the west, very likely a hushing pond from the period when coal was dug from the valley side of Cwm Glo during the late 18th and early 19th centuries. The shaft of Cwm Glo Pit itself is marked by a concrete capping. It was operated by a water balance whose pond was 70m to the NW. The pond is now dry but the earth and stone U-shaped dam survives. Morris and Williams note that "The water balance pit, used where there was an abundant supply of water, was peculiar to South Wales… In 1862, in Glamorgan alone, there were about sixty of these machines at work, all the great pits of the Cyfarthfa works being operated on this basis" (Morris and Williams, The South Wales Coal Industry 1841 - 1875 (1958), p. 70). Several stretches of stone sleeper blocks are visible along the lines of the former tramroads that led from the shaft. One took the ironstone onto the flat top of the waste tip where a network of branch roads was created (still visible as low earthworks) so that the ore could be left exposed to be broken down by the frost before delivery to the Cyfarthfa furnaces. The monument is of national importance for its potential to enhance and illustrate our knowledge of the late 18th and early 19th century coal mining and iron working industries. The history of the site dates back into the later 18th century and the remains comprise a well preserved complex of early features typical of the techniques used on the Cyfarthfa Estate during the height of the ironworks production. The area to be scheduled comprises the remains described and an area around them within which related evidence may be expected to survive. It is irregular in shape on plan and measures up to 346m from N to S by up to 310m transversely. The outer edge of the waste tip is unstable and the scheduled boundary has been drawn to exclude areas which may require re-profiling.