CPAT Regional Historic Environment Record
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Nant yr Eira Mine

Primary Reference Number (PRN) : 725
Trust : Clwyd Powys
Community : Llangurig
Unitary authority : Powys
NGR : SN82708730
Site Type (preferred type first) : MULTIPERIOD COPPER MINE / MULTIPERIOD LEAD MINE
Status : scheduled monument

Description :
Lead/Copper (Prehistoric/1883)

Geology
Ordovician Lower Van Formation grits. The vein strikes N-S and E-W. Mineralisation includes chalcopyrite and lead with quartz gangue

Workings
A shaft is located to the east of the dressing floors at SN82738744.

There is a long prehistoric opencut on the lode to the north of the dressing floors SN82628746 with a 19th c. shaft through its base at the southern end. The Nant Yr Eira stream was formerly diverted around the top of these workings in a leat but now cascades into the workings as a waterfall at the northern end.

Another shaft is located near the source of Nant Yr Eira to the north-west at SN82208660.

There are numerous trials on the hillside to the east of the stream at SN82678747.

Transport
Short sections of tramroad extend along the 19th century spoil tips from the 2 shafts close to the dressing floors. One of these can be traced to 2 ore bins while the other ends to the rear of the crusher house.

Power
There are 2 wheelpits on the dressing floors. One of these drove the crusher house (38x3ft) and also aided pumping. The other smaller wheelpit is located to the south of the platform on which the crusher wheel sits, its use is not clear. A reservoir exists upstream of the junction of Nant Yr Eira with the Afon Hore at SN82658773.

Processing
Surviving remains include a crusher house, 2 round buddles and an ore bin with a picking table platform in front. Jiggers were presumably placed on the platform in front of the large wheelpit. All centred on SN82668731

Other features
A mine office is located to the east of the dressing floors and a magazine is sited on the hillside to the south-east at SN82908723.
(CPAT Metal Mines Survey)

1. Location
1.1 The mine site remains on the edge of the Hafren Forest to the E of Plynlimon, in a clearing on the NE bank of the Nant yr Eira.

2. Geology
2.1 Solid geology - Ordovician rocks of the Lower Van formation gritstones. Mineralisation includes chalcopyrite and galena.

3. The Survey
3.1 The purpose of the survey was to record the surviving features of the site that appear to relate in general to the 19th century workings and to link these findings to the 1988 excavation and survey area (Timberlake, 1990) of the prehistoric open-cut and tips, which already form a Scheduled Ancient Monument (Mg 226). The open-cut (PRN 18531) is a deep rock-cut linear feature 95 x 6 x 7m deep (Timberlake, 1990). The vein has been worked out from the surface. Documentary evidence refers to lead ore being cleared out of this early cut in the 19th century (Bick 1977, 29). An 1859 plan (DD/WY/5334) shows the re-worked open-cut, a level and a smithy.

3.2 Bronze Age Workings
3.2.1 Excavations of the potentially early spoil tips by Oliver Davies (1938, 55-60) in 1937 led to the discovery of hammerstones and muller-querns. Surface layers of charcoal and burnt stone suggested fire-setting. As a result of this early evidence, the site was examined for dating evidence in 1988, by the Early Mines Research Group (Timberlake 1990, 15-21). Two trenches (PRN 18692) were excavated, again revealing charcoal, and hammerstones were recovered from the lower layers. Radiocarbon dating from wood samples by the British Museum gave dates within the Early Bronze Age, c2000-1500 Cal. BC.

3.2.2 The stream now flows naturally N-S through the open-cut, but the course of the stream appears to have been diverted to the W of the opencut in the 19th century to allow further working. A channel (PRN 18694) on the west banks of the open-cut is the suggested course of the diverted stream. The 19th century tips probably overlie prehistoric tips in the area to the SE of the opencut.

3.3 19th Century Workings
3.3.1 The mine was worked by the Snow Brook Mining Company from 1858 until 1887, when mining operations were suspended. During this period, Bick (1990, 29) documents 33 tons of lead ore being recovered from clearing out the open-cut. The cut does not appear to have been worked any further.

3.3.2 The main shaft (PRN 18546) and large spoil tip lies in the forestry to the E. A raised trackway (PRN 18642) connects the shaft to the mine site.

3.3.3 The main tramway (PRN 18534), constructed of mine waste, would have transported ore from the re-worked open-cut. It terminates in a platform area and two ore-bins (PRN 18535) N of the crusher house (PRN 18537). To the N of the ore-bins, a the collapsed stone walls of a sunken shelter (PRN 18369) survive c.1m high in parts. The platform area in front of the ore-bins facilitated the carriage ore presumably via a wooden chute to the crushers.

3.3.4 The leat (PRN 18533), partly stone revetted, runs parallel to and N of the main tramway (PRN 18534) from the open-cut. A low wall of mine waste c.1m wide descends to a "bridge" on the S of the open-cut, which appears to have carried the stream by launder across to feed the crusher house leat. Pier-base PRN 18696 indicates the bridging site. The leat terminates above the crusher house wheelpit (PRN 18536) which it must have powered via a launder.

3.3.5 Bick (1977, 28-29) refers to a 38 x 3ft waterwheel and 24" crusher coming up for sale in the 1860s. The substantial stone walls of the crusher house (PRN 18537) and wheelpit (PRN 18536) complex have partly-dressed stone quoins. The crusher house abutts the wheelpit on its E side (see Plate 7). Also adjoining the wheelpit and crusher house wall is a platform area (PRN 18461) into which ore was fed by a chute which appears in the crusher house wall. A substantial raised square platform area c.12 x 10m (PRN 18538) adjoins the crusher house complex on its S side, where a drainage culvert appears to emerge from under the higher sorting platform area. An area of fuel-ash slag on the platform surface suggests the use of a portable steam engine. Two iron tie-rods survive on the S wall of the raised platform and two appear to have been sited on the W wall also.

3.3.6 The tailrace from the wheelpit arch ( 0.7m high x 0.7m wide) is channelled out of the NW corner of this sorting area and possibly ran in a culvert along the W side of the platform. It appears also to have fed the buddle (PRN 18539) via a launder. The buddle survives as a circular earthwork c.4.6m diameter with a 0.6m wide bank around it, W of the large platform area. Buddle waste lies to the S and W of the feature.

3.3.7 A second buddle (PRN 18543) c.4m wide with its central support post still in situ lies alongside the forestry fence on the S.E extremity of the mine site. Buddle waste surrounds the area and the circumference of the buddle is defined by protruding gritstone blocks. The buddle was presumably fed by a raised launder.

3.3.8 The tailrace from the crusher wheelpit appears to have fed two reservoirs (PRN 18541) which fed water via a stone culvert (PRN 18352) towards the jig platforms (PRN 18542) and the second buddle (PRN 18543). There are three possible jig platform areas (PRN 18695) and a mound of jig waste on the S bank of the stream. A further spoil mound is located on the SW bank of the stream.

3.3.9 To the S of the platform area (PRN 18538), a second wheelpit (PRN 18540) c.5.2 x 1.3m internally, is located. A launder may have carried the leat over the reservoirs (PRN 18541) to power an overshot wheel. Presumably this wheel powered the jiggers. The tailrace may have been culverted out into the stream. The wheelpit is abutted by grassed-over mounds of jig waste. To the W of the wheelpit PRN 18540, on the SW bank of the stream, a large spoil tip remains possibly indicating the site of a blocked level (PRN 18640).

3.3.10 The collapsed stone walls of a building, probably the mine office or smithy (PRN 18544) survive to 1m high at best. A doorway is located in the W wall and evidence of a fireplace or chimney remains on the SE corner.

3.3.11 The original access was via a track (PRN 18641) that now emerges from the forestry on the eastern side of the mine.

3.3.12 An area of quarrying (PRN 18697), probably for stone for the mine buildings, is located on the N side of the tramways. Further N of this quarry an a second area of quarrying (PRN 18693) is located.

3.3.13 A trial pit N of the open-cut, is located outside the survey area.

3.3.14 A small enclosure (PRN 18545) c.2.5m sq lies to the E of the site. A large 19th century tip below the mine track (PRN 18641) obscures the NW corner of the enclosure, which is possibly a sheepfold.

4. Conclusions
4.1 The site as a whole provides an important example of diverse mining techniques relating to widely differing period of exploitation. The Bronze Age workings are already protected as a Scheduled Ancient Monument and it is recommended that the existing area be extended to include those features of 19th century date.
(CPAT Metal Mines Survey - ground survey)

Scheduled area revised to encompass the surface of the Bronze Age and 19th century mines. An area to the west has been removed and another to the north-west, which contained the main prehistoric opencast, added. Other minor alterations. (Cadw 1997).

Scheduled area revised again to encompass further features identified during the Forest Enterprise WHAP, including a reservoir and 2 adits upstream from the open cut to the north (Cadw, 2000).

Sources :
Anon , 1860 , title unknown - Nant yr Eira Mine
Anon , 1880 , title unknown - Nant yr Eira Mine
Bick, D E , 1977 , The Old Metal Mines of Mid Wales 4
Bick, D E , 1978 , The Old Metal Mines of Mid Wales 5
Bick, D E , 1980 , title unknown - Montgomery Metal Mines list , Archaeology in Wales : 36 : 83
Bick, D E , 1990 , The Old Metal Mines Of Mid-Wales
Cadw , 1994 , Scheduling map - Mg226(POW)
Cadw , 1997 , Scheduling map - Mg226(POW)
Cadw , 2000 , Cadw Field Monument Wardens Report - Mg226(POW)
Cadw , 2014 , Scheduled Monument consent letter
Clwyd Powys Archaeological Trust , 1983 , Site visit record - PRN725
Clwyd Powys Archaeological Trust , 1984 , CPAT Project Archive
Clwyd Powys Archaeological Trust , 1996 , Site visit record - PRN725
Davies, O , 1938 , Ancient Mines Of Montgomeryshire , The Montgomeryshire Collections : 45 : 58-
Foster-Smith, J R , 1978 , The Mines of Montgomeryshire and Radnorshire
Frost, P , 2001 , Hafren Forest, Nant-yr-Eira Mine , Archaeology in Wales : 41 : 125
Frost, P , 2001 , Nant Yr Eira Mine, Hafren Forest, Photographic Survey ( © Frost, P)
Hamer, E , 1870 , A parochial history of Llangurig , The Montgomeryshire Collections : 3 : 232-300
Jones, N W and Frost, P , 1996 , Powys Metal Mines Ground Survey 1994 ( © Clwyd Powys Archaeological Trust)
Jones, O T , 1922 , Lead and Zinc. The Mining District of North Cardiganshire and West Montgomeryshire
Ordnance Survey , 1885 , OS map
Ordnance Survey , 1978 , OS record card SN88NW 4
Royal Commission on the Ancient and Historical Monuments of Wales and Monmouthshire , 1911 , Inventory of the Ancient and Historical Monuments of the County of Montgomery ( © Royal Commission on the Ancient and Historical Monuments of Wales and Monmouthshire)
Thomas, D , 1998 , Hafren Forest Archaeological Assessment ( © Clwyd Powys Archaeological Trust)
Timberlake, S , 1990 , Excavations at Parys Mountain and Nantyreira
Walters, M , 1993 , Powys Metal Mines Survey , Archaeology in Wales : 33 : 43-44
Williams, C. J., & Bick, D , 1992 , List of metalliferous mine sites of industrial archaeological importance

Events :
13020 : Nant yr Eira Mine, excavation 1994 (year : 1994)
64006 : Nant yr Eira Mine, photographic survey 2000-2001 (year : 2000-1)
18692 : Nant yr Eira Mine, excavation 1988 (year : 1994)
106571 : Nant Yr Eira mine, photographic survey 2001 (year : 2001)
123076 : Powys Metal Mines, topographical survey 1994 (year : 1994)

Related records
CPAT Historic Environment Record (HER) 725

Compiled date : 31-12-1984


Images :



Archaeological data, from the Historic Environment Record, supplied by The Clwyd-Powys Archaeological Trust in partnership with Local Authorities, Cadw and the partners of ENDEX © CPAT, 2025 (and in part © Crown, 2025). It is intended to be used for private research only and is not for use as part of commercial projects. If you wish to use this information for publication in printed or multimedia form or to compile resources for commercial use, prior permission must be obtained in writing. Use of this information is subject to the terms and conditions of access to HER data published on CPAT's website. Please contact the HER if you have any further questions regarding this information. Please quote the Primary Reference Numbers (PRNs) in any correspondence.

April 22, 2025, 12:07 pm - File produced for Archwilio from CPAT's Regional HER.
Clwyd-Powys Archaeological Trust, The Offices, Coed y Dinas, Welshpool, Powys, SY21 8RP
tel (01938) 553670, email her@cpat.org.uk, website www.cpat.org.uk

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