Garnddyrys (Site Of) and Adjacent Tramway (MM189)
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Scheduled Monument Damage Assessment Report 16th November 2017 Garnddyrys (Site of) and adjacent Tramway (MM189) Figure 1 View of new cave entrance dug through the tramway Cadw – SM Damage Assessment Report – MM189 – Garnddyrys (Site of) and Adjacent Tramway This damage assessment report has been produced within the Historic Environment Branch of Cadw. Cadw, Welsh Government Plas Carew Unit 5/7 Cefn Coed Parc Nantgarw Cardiff CF15 7QQ Telephone: 01443 336000 Email: [email protected] © Crown Copyright 2017 Cadw yw gwasanaeth amgylchedd hanesyddol Llywodraeth Cymru, yn gweithio i sicrhau amgylchedd hanesyddol hygyrch a ddiogelir yn dda i Gymru. Cadw is the Welsh Government’s historic environment service, working for an accessible and well-protected historic environment for Wales. www.cadw.cymru.gov.uk www.cadw.wales.gov.uk 2 Cadw – SM Damage Assessment Report – MM189 – Garnddyrys (Site of) and Adjacent Tramway Contained within this report: 1. Non-Technical Summary ........................................................................................................ 5 2. Monument Description ........................................................................................................... 5 3. Objectives .................................................................................................................................. 7 4. Site Visit Report ........................................................................................................................ 7 5. Map of the Scheduled Area highlighting area of damage ............................................... 12 6. Conclusions ............................................................................................................................. 13 7. Recommendations .................................................................................................................. 13 8. Requirements .......................................................................................................................... 14 8.1 Ancient Monuments and Archaeological Areas Act, 1979..................................... 14 3 Cadw – SM Damage Assessment Report – MM189 – Garnddyrys (Site of) and Adjacent Tramway SAM name and Garnddyrys (Site of) and adjacent Tramway reference number Grid reference SO 25500 11301 Cadw / MA / AM Grant: Cadw funded schemes (MA /AM None Current Grant) Non-Historic Environment None Designations Dr Amelia Pannett Field Monument Warden Cadw Report produced Welsh Government by Cadw FMW Tel: 01633 866410 Mobile: 07837 213453 E-mail: [email protected] 4 Cadw – SM Damage Assessment Report – MM189 – Garnddyrys (Site of) and Adjacent Tramway 1. Non-Technical Summary The following report details the results of an assessment of damage to a section of Hill’s Tramway which forms part of the extensive scheduled area of MM189 and lies within the Blaenavon Industrial Landscape World Heritage Site. The damage incident had been reported to Cadw by the landowner, XXXXXXXX. A site visit was subsequently carried out by the Cadw FMW accompanied by a representative of BWHEG. It was found that a hole, measuring approximately 1m long and 1m wide had been dug through the surface of the tramway to access part of the Ogof Draenen caving system. Stones and soil were found around the hole, and the hole had been partially covered by a small metal grille and a piece of hardboard. A crowbar and a spread of soil were found on the ground to the west of the hole. The site visit was undertaken by Dr Amelia Pannett, Field Monument Warden, accompanied by XXXXXXXX of Blaenavon World Heritage Environment Group on the 15th November 2017 in dry and bright conditions. 2. Monument Description The following provides a general description of the Scheduled Monument. The monument consists of the remains of an iron forge and section of tramway located at 1300ft AOD on the NW side of the Blorenge mountain. The forge forms part of the complex of industrial sites associated with the Blaenavon Ironworks, and is where pig iron from the furnaces in Blaenavon was converted into wrought iron bars or rails. At its peak, the forge employed 450 people and produced 200 tons of wrought iron per week. The forge at Garnddyrys was built in 1817 by the Blaenavon company and consisted of a complex of steam powered furnaces, puddling furnaces and rolling mills together with a weighing house and houses for the workers. Pig iron was brought from the ironworks in Blaenavon along Hill’s Tramway, a primitive railway built by Thomas Hill 5 Cadw – SM Damage Assessment Report – MM189 – Garnddyrys (Site of) and Adjacent Tramway in the years after 1815. The tramway passed through the Pwll Du Tunnel to Garnddyrys and then around the Blorenge to Llanfoist. The construction of the section of tramway to the S of the forge complex, included in the scheduled area, involved cutting a terrace into the steep hillside and building a substantial retaining wall. In places the sleeper stones that would have held the rails in place can still be seen through the turf. There are the remains of a stone building adjacent to the tramline to the S of the forge and this is thought to have been a blacksmiths shop. The tramway continues N through Garnddyrys, entering a cut and cover tunnel at the N end of the lower pond. This extends for around 150m and was built to prevent the tramway from being buried beneath piles of slag from the forge. On the forge site are the remains of two large ponds, the N of which (upper pond) would have supplied water to the steam engines that powered the furnaces. Water would have been fed into the upper pond from the slopes of the Blorenge above. Records reveal that there were two steam engines on the site, providing blast for the furnaces. The arched outlet through which water was fed to the steam engines can be seen towards the top of the retaining wall on the W side of the upper pond. Below the retaining wall are the foundations of the forge buildings, including a structure called the Manager’s house that was excavated in the 1970s – this large building had a cellar and two fireplaces but given its proximity to the forge is unlikely to have had a domestic function. At the N end of the site, immediately N of the furnaces, are the foundations of workers cottages. These form three sides of a square, with the N and S sides more easily discernable. On the W side of the site is a large and distinctive heap of slag, and the W slopes below the forge are littered with boulders of slag up to several metres across. The site ceased production in the 1860s, and was replaced by the new forge at Forgeside. It had become uneconomic to transport pig iron to this remote forge site after the railway came to Blaenavon and replaced the canal as the main means of transport in the 1850s. 6 Cadw – SM Damage Assessment Report – MM189 – Garnddyrys (Site of) and Adjacent Tramway The monument is of national importance for its potential to enhance our knowledge of 19th century iron working and other 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 iron forge 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. 3. Objectives To objectively record and report any damage that has occurred within the scheduled area. To also report on any damage within the immediate vicinity of the site, in respect of any adverse impact this may have had upon the monument and its setting. 4. Site Visit Report The section of Hills Tramway to the south of Garnddyrys comprises a level surface up to 4m wide terraced into the hillside. On the eastern side the tramway is bounded by the limestone cliff formed during the construction of the tramway, while to the west is the substantial retaining wall. The retaining wall has several areas of collapse along this stretch of the tramway and is unstable in parts. The scheduled area is 9m wide in this area, and covers the whole of the tramway, the retaining wall and the limestone cliff. The tramway is a footpath, forming part of the ‘Iron Mountain Trail’ and is well-used by walkers. The hole has been excavated into the eastern side of the tramway, at the base of the limestone cliff. It is located approximately 140m north of the footbridge at a point where soil has slumped down from the slopes above and partly covered the eastern side of the tramway. The excavations to open the hole involved cutting into and removing a section of the slumped soil, which appears to have been disposed over downslope of the retaining wall. 7 Cadw – SM Damage Assessment Report – MM189 – Garnddyrys (Site of) and Adjacent Tramway The hole measures approximately 1m by 1m at the surface and cuts through both slumped soil overlying the tramway and material that make up the trackbed of the tramway - the disturbed soil surrounding the hole includes black and cinder-rich materials that are known to have been used in the construction of tramways throughout the World Heritage Site. The depth of the dug hole is difficult to determine due to the covering grille and board, however the hole opens up into a vertical shaft with solid rock on each side approximately 0.5m below the surface. A fixing