CPAT5925

CPAT Regional Historic Environment Record
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Cwm Orog Mine

Primary Reference Number (PRN) : 5925
Trust : Clwyd Powys
Community : Llangynog
Unitary authority : Powys
NGR : SJ05202730
Site Type (preferred type first) : MULTIPERIOD LEAD MINE

Description :
Lead/Zinc/Barytes (Prehistoric ?/Roman ?/Medieval ?/1747-19)

Geology
Ordovician slates, shales and felsites dominate the geology. There is a main ENE-WSW vein with N/S barytes cross-courses. Mineralisation of the main vein includes lead and zinc.

Workings
'Old Workings' were described as being present in 1747. Opencuts and stopes can be seen on the northern slopes of Craig Rhiwarth on the barytes lode & main lode.

There are 10 levels in all including adits below the northern scarp of Craig Rhiwarth from SJ05022727 to SJ05272728. There is a single shaft at the top of the hill SJ05272728. Surface workings are visible at the western extent of Pencraig and probably represent early trials for the western extent of the lode SJ04832681.

Transport
There is a 3 phase system which is unique in the Mid Wales orefield including: (1) 2 contour tramways connecting to long oreslides (2) 1 incline tramway (3) An aerial ropeway.

The three contour tramways are well preserved as are the ore chutes at their extremes. Only the upper foundation base of the aerial ropeway winder survives. The incline survives as a footpath.

Many of the adits display earthwork traces of tramway beds. At the uppermost level entrance remains of rails can be seen.

Power
Two leats from Nant Bryn Mawr lead to the dressing floors. There is a 17 x 2ft wheelpit on the dressing floor with an in situ axle. This waterwheel drove the crusher and buddle.

Processing
There is a crusher house, stone breaker platform, three earthwork settling tanks, a single buddle and a jigger shed all centred on SJ04732736.

The ore chutes/bins at the head of each contour tramway are in direct association with washing/picking floors. Each of the ore bins is constructed to a slightly different design.

Other features
No evidence.
(CPAT Metal Mines Survey)

1. Location

1.1 The mine site is located on the northern slopes of Craig Rhiwarth about 2km NW of Llangynog. The dressing floor areas at the western end of the mine lie to the E side of the B4391 Llangynog to Bala Road and the workings run eastwards uphill towards the hillfort of Craig Rhiwarth (PRN 1466) for c.650m.

2. Geology

2.1 Solid geology - Ordovician slates and shales. An ENE-WSW vein included galena and sphalerite with a N-S barytes cross-cut.

3. The Survey

3.1 Workings

3.1.1 Early workings (PRN 18396) appear as linear cuts and small depressions on the northern slopes below Craig Rhiwarth Hillfort.

3.1.2 A track (PRN 18405) runs downhill, cutting through the hillfort ramparts to an area of trials (PRN 18406).

3.1.3 To the W of the trials, a run of collapsed stopes (PRN 18401) are probably outcrops on the main vein. An open collapse between the open-cuts appears to fall into the level below, and has previously been misinterpreted as a shaft.

3.1.4 A series of levels are driven into the hillside along the entire length of the mine site. It was not possible to date the majority of these workings, although the latest are located uphill from the aerial ropeway top station and the head of the incline at the top (E) end of the site. Not all of the levels are described individually below.

3.1.5 Five levels (PRNs 18397-18400, 18402) were identified in the area above the aerial ropeway top station. A small area of waste fans out from the top level PRN 18397, possibly an 18th century venture, and the larger areas of spoil lie N of levels PRN 18398 and 18400.

3.1.6 Ore was carried out of these levels by a tramway (PRN 18407) connecting to the aerial ropeway top station (PRN 18408).

3.1.7 A small building (PRN 18404) probably a shelter or store is located near the entrance of level PRN 18400.

3.1.8 The large level PRN 18399 appears to have superseded level PRN 18402, being driven in below it to meet the main vein. A small building (PRN 18403) is located between these two levels.

3.1.9 Two substantial levels (PRNs 18416 and 18419) with stone revetted entrances lie near the mid-point of the workings. The masonry walls of a rectangular building (PRN 18643) c.3 by 2.75m remain sunk in the ground to the E of the large spoil mound from level PRN 18416. A further level (PRN 18417) is located to the SW, with a small building platform (PRN 18668) downhill of it.

3.1.10 The drainage adit surveyed by the OS in 1889 to the NW of Waen Cottage and further evidence of workings to the N of the modern fence-line remain outside of the survey area.

3.2 Processing

3.2.1 The main 19th century processing area lies at the W end of the site. However, earlier processing may be associated with building PRN 18420 and the adjacent platform PRN 18423. A track leads downslope from the area, cut by the later tramway PRN 18411, to a roughly circular depression (PRN 18424) which is a possible ore-bin.

3.2.2 The dressing floors (PRN 18444) lie at the bottom of the hillside, although most of the processing area has been levelled. The remains of large masonry piers (PRN 18445) on the W side of the dressing floor supported a tramway carrying ore from the lower terminus of the aerial ropeway to the crusher house (PRN 18443).

3.2.3 A waterwheel pit (PRN 18442), c.8 x 2.5m externally, drove the crusher rolls and possibly powered a buddle. Parts of the cast-iron waterwheel remains embedded in the wheelpit (see Plate 3).

3.2.4 The waterwheel was fed by a leat (PRN 18435) running into the site from the N, diverted from the Cwm Orog stream. The line of a possible leat or drain (PRN 18439) lies further to the W.

3.2.5 Two concrete bases are all that remain visible on the dressing floor area alongside the crusher house. Retaining walls form a series of platforms above the bases.

3.2.6 A modern track cuts through the dressing floor areas and leads up to Waen Cottage. Below the track, lines of several parallel settling pits (PRN 18437) are passed to the W by the tailrace from the wheelpit (PRN 18664). A short length of old mine entrance track (PRN 18440) is located west of the settling pits.

3.2.7 A possible leat (PRN 18438) runs in from the N below the stream and the settling pits.

3.2.8 The foundations of the smithy (PRN 18436), which includes a standing fireplace, remain to the N of the modern track.

3.3 Transport

3.3.1 The site provides unique evidence of three different systems of transporting ore, demonstrating improving technology.

3.3.2 The earliest system of transport consists of four tramways which contour the hillside to facilitate the carriage of ore downhill, via a series of long ore-slides. The ore-slides would have been constructed in timber, and little trace remains. The difference in their associated structural features suggest that they relate to different periods of activity. Not all of the tramways need necessarily to have been in contemporary use.

3.3.3 The highest contour tramway (PRN 18410) runs S and W from the top of the incline. The tramway has been disturbed by the later barytes workings (PRN 18676) which appear as two open-cuts with a level (PRN 18414) driven in to the western cut. Two levels (PRN 18415-18416) below the tramway are surrounded by spoil from the barytes vein. Barytes was mined from 1915 to meet the demands of World War 1. The tramway terminates in a substantial ore-slide (PRN 18421), headed by a semi-circular stone ore-chute (PRN 18644). The base of the ore-slide is c.20m E of building PRN 18420.

3.3.4 A second tramway (PRN 18411) contours W from midway along the site, presumably serving the level above (PRN 18419). Ore was loaded into a sub-rectangular stone ore-bin (PRN 18422) to be sorted and then transported W along the tramway. At the W end of the tramway, ore was tipped into a stone-lined chute (PRN 18645) constructed on exposed bedrock, and thence downhill via ore-slide PRN 18429. A pier base (PRN 18583) midway down the ore-slide would have bridged it over tramway PRN 18412, which may therefore be contemporary.

3.3.5 Tramway PRN 18412 runs W from the semi-circular stone ore-bin (PRN 18427), located SW of the incline terminus. A platformed sorting area lies in front of the ore-bin with a revetment wall surviving where ore was loaded onto the tramway. At the W end of the tramway, lie the earthwork remains of an ore-slide (PRN 18432), where ore appears to have been loaded into ore-bin PRN 18652.

3.3.6 The lowest, and possibly earliest tramway (PRN 18413) appears to have been associated with a possible ore-bin PRN 18430 and building platform (PRN 18431). They were presumably connected by a short ore-slide (PRN 18661).

3.3.7 The two upper tramways and ore-slides were probably superseded by the construction of the incline (PRN 18409). The steep bed of the incline appears as a track c.2.1m wide running E-W parallel to the modern fence-line from the upper levels of the mine. Ore was presumably unloaded from the trucks at the base of the incline onto the short tramway (PRN 18677) leading to ore-bin PRN 18427.

3.3.8 The aerial ropeway (PRN 18408) was presumably the more recent means of transporting ore from the upper levels westwards and downhill to the dressing floors. The foundation of the upper winding terminus remains to the N of the main level. Earthwork evidence and stone foundations remain of the platforms that supported the pillars carrying the ropeway downhill to its lower terminus platform (PRN 18441).

4. Conclusions

4.1 Although the overall preservation of the site varies considerably, elements within it may be considered of national importance. In particular, the varying methods of transporting the ore to the dressing floors provide important examples of changing technology. The contour tramways are also notable as forming a system of transport unique to this orefield. Scheduling of the whole site is therefore recommended to preserve the remaining features.

4.2 Although early, probably 17th century workings are located on the northern slopes of the Craig Rhiwarth Hillfort, there is no certain evidence of ancient workings contemporary with the hillfort. Powys Estate manuscripts record mining at Cwm Orog from 1706 (Powys MS 3029, National Library of Wales) and documentary evidence suggests that various trials had taken place with very little success prior to 1751 (Powys MS 21712, National Library of Wales).

4.3 Williams (1985, 99-101) suggests that No.1 Level referred to in a 1922 Geological Survey is located in the area of PRN 18398 or 18400. The No.2 Level of this survey would be PRN 18402, which was superseded by the main No.2 Level PRN 18399.

4.4 Level PRN 18416 is probably the Level 3 referred to in the 1922 Geological Survey.

4.5 Williams (1980, 96-7) refers to a report in the 1870 Mining Journal which states that No1-4 levels were being driven into the hillside. No.1 and No.2 Level were reportedly connected and working by 1872 when the Cwm Orog Silver-Lead Mining Company was formed. No.4 Level of this group was downhill of No.3 and west of the barytes lode. Hughes' Level probably refers to the drainage adit alongside the stream that remains outside of the survey area.

4.6 The 1870 Mining Journal refers to the stream being diverted to power the waterwheel (PRN 18442) and the dressing floor being under construction.

4.7 The incline appears to have been self-acting. Any certain evidence of a crossing point may have been lost in the field of improved pasture which now lies on the other side of the modern fence-line.

4.8 The aerial ropeway may have been installed by the Cwm Orog Mines Ltd., who worked the site from 1908-1911. Mining returns (Burt et al 1990, 55-56) record 42 people employed in 1908, considerably more than in previous years.

4.9 The site was reportedly worked for roadstone c.1912 from the quarry PRN 18434.

(CPAT Metal Mines Survey - ground survey)

There may be some prehistoric mining in this area, a possibility which is suggested by the close proximity of Craig Rhiwarth hillfort and the fact that prehistoric smelting evidence was found in excavations at Llwyn Bryndinas, further down the Tanat valley. (RH 13/01/2010)

Sources :
Bick, D E , 1978 , The Old Metal Mines of Mid Wales 5
Bick, D E , 1990 , The Old Metal Mines Of Mid-Wales
Clwyd Powys Archaeological Trust , 1983 , Site visit record - PRN5925
Clwyd Powys Archaeological Trust , 1984 , Site visit record - PRN5925
Foster-Smith, J R , 1978 , The Mines of Montgomeryshire and Radnorshire
Hankinson, R , 2010 , Mines and Quarries. The Scheduling Enhancement Programme (

© Clwyd Powys Archaeological Trust)
Lewis , 1968 , title unknown - Cwm Orog Mine
Ordnance Survey , 1887 , OS map
Williams, C. J., & Bick, D , 1992 , List of metalliferous mine sites of industrial archaeological importance
Williams, R A , 1985 , The Old Mines of the Llangynog District
Wren, W J , 1968 , The Tanat Valley, its railways and industrial archaeology

Events :
123076 : Powys Metal Mines, topographical survey 1994 (year : 1994)
115395 : Mines and Quarries: Scheduling Enhancement Project, assessment project 2010 (year : 2010)

Related records
CPAT Historic Environment Record (HER) 5925

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 20, 2025, 12:35 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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