CPAT Regional Sites & Monuments Record

PRN 5942 - Dyfngwm Mine ; Castle Rock Mine (multiple site)
Scheduled Ancient Monument Mg247(POW)

Lead/Zinc/Copper (Roman/Medieval/Post-Medieval/1840s-1935)

Geology Silurian Frongoch & Gwestyn formations. Shales and mudstones. The Dyfngwm lode is the southern branch of the Dylife lode with an ENE strike. Mineralisation includes galena, chalcopyrite and zincblende with quartz and calcite gangues.

Workings A deep adit in the gorge connects with Boundary Shaft on the top of Pen Dylife at SN85219335.

There is a possible hushing channel to the north west of Boundary shaft which descends the southern flank of Y Grug at SN84909331. It would appear to have been fed by breaking a hole in the earthen bank boundary to the north which allowed water following the boundary ditch to be diverted southward into the prospecting hush. A circular earthen bank at the head of this possible hush may have been a storage pond/hushing dam although it lacks a sluice.

Another possible hushing site lies just below the Roman fortlet of Pen Y Crogbren at SN85709338 where the earthworks of a suspected rectangular hushing dam can be seen next to the old trackway. A narrow prospecting hush channel can be seen on aerial photographs exiting from the western corner in a southerly downslope direction.

A quarry-like opencast is located near the 1935 processing mill at SN84909315.

Some trials and clearly more productive workings can be seen on the top of the hill which take the form of opencuts, adits, shallow shaft-mound type workings, deep shafts and levels in the base of the opencuts. These workings are clearly attempts to locate extensions to the Dylife and Dyfngwm lodes. The workings on both of these lodes trend ENE/WSW and run from SN84829326 to SN85789342, a total distance of 1km.

Three levels are particularly interesting as they are probably of great age; all are run-in and one has produced evidence of manual dressing in the form of stone mortarstones buried in the tips. All have a small but constant amount of water exiting from the buried entrances. They are located at SN85379300, SN84959325 and SN85069333.

Further west along the Clywedog gorge are a number of levels at varying heights in the hillside between SN84789317 and SN84329313.

Castle Rock SN84229310 is probably one of the best natural lode exposures in Wales. At the foot of the rock are numerous trials, a shaft, level and wheelpit.

Transport Tramways lead from the main adit SN84929315 to inclines for carrying the ore down to the dressing floors along the banks of the River Clywedog.

There is a steep track leading eastwards out of the valley onto the top of the hill. This was probably the route by which the ore transport connected with the old coach road on Pen Dylife and later the Machynlleth road in Dylife.

Power A leat runs into the dressing floors from the Afon Clywedog, traversing the northern side of the valley on its course.

2 waterwheels, stamps and a drawing machine were installed in 1850. In 1856 a steam engine was installed to drive the pump rods in the main adit. In 1858 a 36" condensing engine was added. In 1864 a twin 10" cylinder horizontal engine assisted the pumping wheel. Also in 1864 a steam traction engine was purchased though it probably saw little use. Two wheelpits and engine bases outside the adit entrance are visible.

At Boundary shaft SN85259334 a 60" Cornish pumping engine was installed. Two ten ton boilers were placed alongside the engine. The iron gudgeon from the balance bob is still visible next to the shaft. The engine house has completely collapsed. The reservoir for the boilers is located immediately to the west of the engine remains.

In 1861 a 50x6ft winding waterwheel was erected in Dylife at SN86329400 which was drawing at the Old Engine and possibly also the Boundary shaft. The wire winding cable was carried over Pen Y Crogbren partly in a gully which is still visible for a short distance at SN85789350.

Processing A poorly preserved crusher house is located by the river with two beams for supporting the single pair of crushing rolls at SN84909301.

To the east of this are the substantial concrete and flagstone foundation bases of the 1935 Hirnant Minerals Ltd processing mills SN84879302. These foundations extend from the river and up the hillside to the north. Documentary sources refer to this mill incorporating the following machinery: a 50hp crude oil engine, 16"x9" stone breaker, screens, granulator, shaking conveyor feeder, 24"x14" crusher rolls, two vibrating screens, a 6 compartement Bull Jig, 2 cleaning jigs, a Ball Mill, 4 concentrating tables, a 3" centrifugal pump, two 2" pumps and an elevator.

The slurry left over from the ore concentrator was pumped out to a line of seven connected slime pits which run along the south bank of the Afon Clywedog SN84899302.

Other foundation features on the dressing floor are poorly preserved and difficult to interpret.

Other features Two rectilinear enclosures are located very close to the mining area and may be associated with early mining operations although some caution should be noted in this interpretation as they may also be post-medieval agricultural enclosures.

The largest of these enclosures is located at SN84869322 and consists of a large square bank of earth and stone blocks of approx. 1.5m width and surviving to 0.35m in height with traces of a very shallow ditch on three sides and a deeper gulley on the western side. No obvious entrance was recorded. The enclosure is situated on the rim of the northern side of the gorge above the opencasted area recorded above.

The smaller enclosure is approximately 200yds to the south-west of the large enclosure on the opposite side of a deep gully which descends into the opencast area at SN84809313. The makeup of the earthwork has the same characteristics as the large enclosure and it may be similar in date and function.

Sources:-
Bick, D E , 1977 , The Old Metal Mines of Mid Wales 4 , 14-20
Bick, D E list , 1978 , NO 7 ,
Bick, D E list , 1980 , NO 7 ,
Bick, D E , 1985 , Dylife - A Famous Welsh Lead Mine , 3-30
Bick, D E , 1990 , The Old Metal Mines Of Mid-Wales , 14-18
CPAT visit form , 19 , ,
CPAT visit form , 1983 , ,
Cadw map , 1997 , ,
Foster-Smith, J R , 1978 , "The Mines of Montgomeryshire and Radnorshire ", British Mining 10 , 18 .
Jones, J A & Moreton, N J M , 1977 , The Mines and Minerals of Mid-Wales , 15
Jones, O T , 1922 , "Lead and Zinc. The Mining District of North Cardiganshire and West Montgomeryshire ", Memoirs of the Geological Survey 20 , 155-6 .
OS record card , 1978 , ,
Rees, D M , 1975 , Industrial Archaeology of Wales , 270
Walters, M , 1993 , "Powys Metal Mines Survey ", Archaeology in Wales 33 , 44 .
Williams, C J & Bick, D , 1992 , 'List of metalliferous mine sites of industrial archaeological importance ', in Briggs, C S Welsh Industrial Heritage: a review , 154

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record created 31/12/84 , last updated 11/02/04
The above data are supplied by CPAT in partnership with its Local Authorities and the partners of END, © CPAT SMR partnership, 2004 (and in part © Crown, 2004)

CM - 11/02/04 ( 16:22:11 ) - HTML file produced from CPAT's Regional SMR
Clwyd Powys Archaeological Trust, Curatorial Section, 7a Church Street, Welshpool, Powys SY21 7DL.
tel (01938) 553670 , fax (01938) 552179, email trust@cpat.org.uk , website www.cpat.org.uk