CPAT Regional Historic Environment Record
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Gwestyn Mine

Primary Reference Number (PRN) : 5943
Trust : Clwyd Powys
Community : Llanidloes Without
Unitary authority : Powys
NGR : SN89408610
Site Type (preferred type first) : MULTIPERIOD COPPER MINE / MULTIPERIOD LEAD MINE

Summary :
A copper/lead mine of 1855-1866. Young's shaft and Pearce's shaft have both been filled in and there are numerous trial shafts in the hillside as well as numerous trackways which may predate the mine - possibly old drovers roads. A 30ft waterwheel was used for pumping and drawing the power source from the Gwestyn Brook. The first edition OS map appears to show a pumping engine with flat rods extending to a shaft. A carpenters' shop, smithy and offices were also on site.

The site now consists entirely of earthworks, with no masonry surviving above ground. The main features consist of a series of shafts and collapsed workings. There are also earthwork remains of the leats, boundary banks, reservoirs, settling pits, engine house and other mine buildings, including a magazine.



Description :
Copper/Lead (Pre 19th century/1855-1866)

Geology
Lower Silurian Gwestyn Formation. The Van lode has been exploited on a vein striking ENE. Mineralisation includes a calcite gangue with chalcopyrite and rare galena, sphalerite, chalybite.

Workings
Young's shaft and Pearce's shaft, both filled in, can be seen in the main area of mining activity on the top of the hill at SN89528612. There are numerous trials on the hillside close to the main shafts which take the form of shallow shaft-mound type workings. Two shafts are located in the field to the north at SN89708630. The latter shafts were drained by adits to the north.

Transport
There are an immense number of trackways crossing the site many of which appear to pre-date the mining activity. The majority are aligned east-west along the top of the ridge while others ascend the northern slopes from the valley bottom. These features are best viewed on aerial photographs. It is possible that some of the banks and ditches relate to mine trackways and leats but the majority are probably of unrelated earlier and later traffic activity.

Power
A 30ft waterwheel was used for pumping and drawing. The power source was the Gwestyn Brook. A masonry wheelpit can be seen in a hollow close to the present Llanidloes road and probably relates to the above.

The first edition map appears to show a pumping engine with flat rods extending to a shaft (probably Pearce's) at SN89608611.

Leats and two associated small reservoirs were recorded on the hillside at the time of the field visit.

Processing
No obvious remains other than jigger waste on the spoil tips and areas of manual rock breaking defined by waste rock in sorted heaps.

Other features
A possible two-roomed mine office is shown on the first edition 25" OS map.
(CPAT Metal Mines Survey)

1. Location

1.1 The mine site lies on the hillside to the E of Gwestyn Farm in an upland area S of the Llyn Clywedog Reservoir. The workings slope downhill northwards to Nant Gwestyn.

2. Geology

2.1 Solid geology - Lower Silurian rocks of Gwestyn formation. Mineralisation on an ENE vein includes chalcopyrite, galena and sphalerite with gangue minerals.

3. The Survey

3.1 The site consists entirely of earthworks, with no masonry surviving above ground. The main features consist of a series of shafts and collapsed workings (PRN 18354), sunk to meet an E-W vein in an area of intense mining activity, possibly mainly reflecting 17th and 18th century working. The workings are cut by a modern fence-line and the modern track that runs from the road to Gwestyn Farm. The shafts are of varying size and depth and have suffered considerable collapse and fresh falls were visible during the time of survey. The run of shafts begin in an area of forestry at the SW and continue to run eastwards and downhill increasing from shallow shafts to larger 19th century workings.

3.2 The largest shaft (PRN 18351) is probably that sunk during the 1850s under the management of Captain Pearce (Bick 1990, 33-34). It has the appearance of a deep shaft, possibly 100-200ft, and was probably drained by the stone-lined drainage adit (PRN 18673) on the Gwestyn Brook to the N, outside of the survey area. The shaft appears to have been powered originally by a horse whim (PRN 18352) S of it. Earthwork evidence suggest a whim circle of c.10m dia. on a raised platform. PRN 18351 appears to be one of only two deep shafts on the mine site. Bick (1990, 75) refers to Pearce's Shaft and Young's Shaft being sunk in the 1850-60s period and both being pumped out by a 30ft waterwheel, powered by a leat off the Gwestyn Brook. A letter (DD/WY/5335) from Capt. James Paull to John Taylor dated 4.12.1860 refers to an inspection of the mine, when he was unable to visit the underground workings as the waterwheel was idle. He was informed by the agent Capt. Pearce that the engine shaft had reached the 38 fathom level. The machinery at the mine consisted of a 36" wheel, 3ft 6" wide with a line of 9" rods. A carpenters' shop, smithy and offices were also on site.

3.3 The second shaft PRN 18590 is possibly Young's Shaft documented by Bick (1990, 34) and lies W of PRN 18351. It appears on the OS 1st edition map of 1886 immediately E of the fence-line as a substantial shaft but the shaft and its surrounds had suffered severe fresh collapse during the duration of the survey. Any evidence of the possible capstan circle recorded by Bick has now disappeared.

3.4 To the E of the main shaft (PRN 18351), lie the disturbed earthworks of the engine house (PRN 18350) that appears on the OS 1st edition map of 1886. The engine appears to have pumped the shafts by means of a flat rod system. Little remains of the structure and no plan is discernible. The engine was presumably erected on the site due to the irregularity in operating the waterwheel when the water level was low in the Gwestyn Brook. The waterwheel was sited outside of the survey area, on land sloping down to the brook.

3.5 To the N of the engine house area, the earthwork foundations remain of a two-roomed building (PRN 18348) c.9 x 4m which appears on the 1st edition OS of 1886 and is possibly the mine office.

3.6 To the NW of the main mining area, a rectangular earthwork is all that remains of the magazine (PRN 18346) recorded by the OS 1886 survey.

3.7 The reservoir (PRN 18347) appears on the OS 1st edition map of 1886 and survives as a substantial earthwork c.10.6 x 7.4m internally, with banks up to 1.3m high. Leat PRN 18685 appears to have fed the reservoir from the west, via a sluice on its north-west corner.

3.8 To the E of the engine house remains lie the earthworks of a reservoir (PRN 18349), c.10 x 15m, falling into two levels. Evidence remains of the inlet and outlet sluices and the drainage appears to run off downhill in the direction of the Gwestyn Brook and the levels and shafts that lie outside the survey area.

3.9 The low earthworks of a large reservoir (PRN 18344) c.32 x 14m max. survive S of the modern farm track on the western end of the site. The inlet and outlet sluices can be identified with faint traces of a leat (PRN 18345) flowing E, but there is no certain evidence of how the reservoir was filled.

3.10 To the W of the main shaft (PRN 18351) several linear cuts (PRN 18353) ressemble possible settling pits.

3.11 The site is cut E-W by numerous trackways (PRN 18343) many of which are overlain by later mining activity. Some of the trackways are presumably the old drovers' roads over the ridge on which the site lies. A substantial linear channel (PRN 18589) cuts through the workings in an E-W direction and appears to be only interrupted by the modern farm track.

3.12 Two old boundary banks (PRNs 18683-4) are located north of the mine office.

3.13 To the E of the present road, earthwork evidence and aerial photographs suggest further workings and two levels cut in to the S off Nant Gwestyn, all of which are outside of the survey area.

4. Conclusions

4.1 The future management of the site should be carefully considered since part of the earthworks have already been the subject of forestry plantation. Particular consideration should be made regarding the safety of the site since it was apparent at the time of the survey that several areas were actively subsiding and possibly in danger of serious collapse.
(CPAT Metal Mines Survey - ground survey)

Sources :
Bick, D E , 1974 , The Old Metal Mines Of Mid Wales I
Bick, D E , 1977 , The Old Metal Mines of Mid Wales 4
Bick, D E , 1990 , The Old Metal Mines Of Mid-Wales
Clwyd Powys Archaeological Trust , 1983 , Site visit record - PRN5943
Clwyd Powys Archaeological Trust , 1984 , Site visit record - PRN5943
Foster-Smith, J R , 1978 , The Mines of Montgomeryshire and Radnorshire
Jones, J A & Moreton, N J M , 1977 , The Mines and Minerals of Mid-Wales
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 , 1886 , OS map
Sophie Watson , 2013 , Gwestyn Mine, Glastir HEF Report ( © CPAT)
Williams, C. J., & Bick, D , 1992 , List of metalliferous mine sites of industrial archaeological importance

Events :
123076 : Powys Metal Mines, topographical survey 1994 (year : 1994)
128531 : Gwestyn Mine, Glastir HEF Report (year : 2013)

Related records
CPAT Historic Environment Record (HER) 5943
115061

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, 11:18 am - 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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