Gwynedd Archaeological Trust
Regional Historic Environment Record

Post-Medieval Copper Mines, Parys Mountain

Primary Reference Number (PRN) : 3564
Trust : Gwynedd
Community : Amlwch
Unitary authority : Ynys Mon
NGR : SH44209030
Site Type (preferred type first) : POST MEDIEVAL COPPER MINE
Status : Scheduled Monument

Summary :
Mynydd Parys (Parys Mountain), lies two kilometres due south of the town of Amlwch in the community of Amlwch on Anglesey (Ynys Mon). The mountain is approximately two kilometres long and nearly one kilometre wide, the long axis running nearly north-east to south-west. The highest point is 147 metres above Ordnance Datum, whilst the surrounding area averages 80 m above OD.

The mountain was formerly divided between Cerrig y Bleiddiau farm on the east, on which the Mona mine was developed, and Parys Farm on the west, on which the Parys mine came to be worked. Two opencasts have been opened on the south-east facing flanks, near to the summit level, the Great Opencast of the Parys Mine and the Hillside Opencast of Mona Mine. The flanks of the mountain are partly covered by the extensive tips from these and from underground workings. Ochre and precipitation pits are to be found at various points around the mountain; the important Dyffryn Adda pits and furnace lie to the north, and the Dyffryn Coch precipitation systems are situated at the foot of the southern flank of the mountain.

The mineralisation occurs within a thin sequence of rocks associated with volcanic events at the margin of an ancient sedimentary basin. The sulphide ores consist of chalcopyrite (copper, iron), sphalerite (zinc) and galena (lead). together with large amounts of pyrite (iron). An ore feature is the "bluestone", comprising an intergrowth of these minerals. The ore minerals were subsequently remobilised, giving rise to a complex ore body, occupying fissures or impregnating the surrounding rock.

Excavations in August 1988 confirmed exploitation of the ores in the Early Bronze Age (2000-1500 B.C.). The discovery of twenty-seven Roman copper ingots, eighteen on Anglesey (two on Mynydd Parys itself), six in the former Caernarfonshire and three in Clwyd is strong circumstantial evidence for Roman copper working, and there was some exploitation in the sixteenth and seventeenth century. But it was not until the 1760s, when Messrs Roe and Co. of Macclesfield leased the future Mona mine, that significant discoveries were made and the Mynydd Parys mines became the most productive in the world. The Parys mine was developed by the attorney Thomas Williams.

By the early nineteenth century the mines were in decline, but were reorganised in 1811, under the Cornish Captain James Treweek. He restored the mines to some prosperity throughout a period when smelters were increasingly being supplied from Chile and Cuba, later from Michigan, Spain and Australia. His death in 1851 was the end of an era for the mountain, and operations were thereafter were on a small scale only. Deep mining ceased around the end of the nineteenth century, and in 1958 the last of the precipitation pits were abandoned.

Description :
In the C18th, copper-mining on Parys Mountain was the most productive in Europe, producing about 3,000 tons of ore each year by 1780. The deliberate destruction of the underground workings, later resulted in opencast mining. <1>

The copper mines on Mynydd Parys were de-watered in summer 2003 following concerns over the threat posed to Amlwch by the large volume of very acidic polluted mine water. The drop in water level provided access to 8km of workings in the historic mine, which are being explored and recorded. Features already noted: wooden pump rods, balance bob, pump, air-ducts, mining barrows and a lead manifold. They have been left in situ pending systematic recording. <7>

The copper mines at Mynydd Parys were developed from the 1760s onwards. Mynydd Parys mine itself was worked from 1785 on the western part of the site on land owned jointly by Plas Newydd and Llys Dulas by the lawyer and industrialist Thomas Williams "the Copper King", one of the leading figures of the industrial revolution, who for a number of years effectively controlled the British copper industry (Rowlands, 29-30; Harris passim). Mona mine to the east was on land owned solely by Plas Newydd, and was worked by Roe of Macclesfield from 1864

Mynydd Parys's golden age was the last quarter of the eighteenth century, when 1,200 people might be employed and output might exceed 3,000 tons per annum, but by 1800 operations were already in decline, and underground extraction effectively ceased in the 1880s.

Though the sites have always been called mines, much of the ore came from a large opencast pit and both mines practised another system, whereby ore was obtained from precipitation from the water which accumulated at the bottom of the workings - a method which may be appreciated by the fact that a key dipped in water from the workings will become covered with copper in a matter of seconds. Ochre was also extracted from the water, and a vitriol and alum works functioned for part of the mines' history.

Exact dates for much of the work that went on at Mynydd Parys are elusive, owing to the incomplete survival of the mines' archives. The Mona mine records survive partially intact, but only scattered documents now exist for the Parys mine. It is not known when ochre extraction began, nor when the vitriol works was established. (GAT, 1995)

Sources :
, 1995 , Mynydd Parys Dyffryn Coch Precipitation Pits Survey and Recording ( © GAT)
A. H. Dodd. , 1926 , Transactions of the Anglesey Antiquarian Society and Field Club
Gwyn, D. & Williams, M. , 1996 , A Guide to the Industrial Archaeology of North West Wales
Hadley, A. , 2016 , Proposed Wind Turbine at Nant-y-fran, Cemaes, Isles of Anglesey. Cultural Heritage Impact Assessment. ( © Archaeology Wales)
Lynch, F., Sharp, M. & Williamson, J. , 2009 , Anglesey Past Landscapes of the Coast
Mason, M. & Riley, H. F. , 1993 , Proposed Wind Farm, Parys Mountain, Amlwch, Anglesey: Evaluation ( © GAT)
Gwyn, D. , 1998 , Mynydd Parys Mines: Archaeological Assessment , <2>
Gwyn, D. , 1998 , Gwynedd Metal Mines Survey , <3>
Jones, C. , 1998 , A Report on Power Systems at Parys Mountain , <4>
Rees, D. M. , 1975 , Industrial Archaeology in Wales , <1>
Cadw , 1998 , Landscapes of Outstanding Historic Interest in Wales , <6>
Jenkins, D. , 2003 , Archaeology in Wales , <7>
Various , 2004 , Archaeology in Wales , <8>

Events :
40413 : Gwynedd Metal Mines Survey (year : 1998)
40151 : Proposed Wind Farm, Parys Mountain, Amlwch, Anglesey: Evaluation (year : 1993)
40013 : Mynydd Parys Dyffryn Coch Precipitation Pits Survey and Recording (year : 1995)
45130 : Proposed Wind Turbine at Nant-y-fran, Cemaes, Isle of Anglesey. Cultural Heritage Impact Assessment. (year : 2016)

Related PRNs :

Compiled date :

The above data are supplied by GAT in partnership with its Local Authorities (Anglesey, Conwy and Gwynedd County Councils, and Snowdonia National Park Authority), © GAT 2019 (and in part © Crown, 2019 - as indicated)
This information is supplied for the purposes of personal interest only and may not be used as part of a commercial project.

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